So, What Does 2013 Have In Store?

We are now well into 2013, and the Chinese New Year holiday has just started. Anyone involved with commercial electronics will know what an inconvenience that can be, but if anyone deserves a holiday, it is the Chinese workers! I for one am not going to begrudge them some time off to see their loved ones. This seems like a good time to take stock of what has happened since my last post, and what my intentions are for 2013.

A Sad Goodbye

As 2012 came to a close, I received some bad news. My good colleague and close personal friend Simon Allen of Intravention Electronics passed away unexpectedly. He was only in his mid 40s, and not much older than me. It takes something like this to make you think about your own mortality, and how fleeting life is. Simon and I had come together when a mutual friend of ours was going through a difficult time. We had known each other for some time, but didn't realise we were in the same business. 

Since then we had worked together on several projects - Simon was a great sounding board for my ideas and an excellent "sanity" checker. When Simon passed away we were working on a couple of commercial products. It is a great sadness to me that Simon took with him so much good humoured knowledge and experience. 

That rather took the wind out of my sails, forcing me to drop a lot of stuff I was working on. Obviously I don't want to go into details here, but I am now considering whether it might not be the right time to move back into permanent employment rather than being a freelance.The recession is dragging on, and life as a freelancer isn't looking too good here.

Onwards...

Anyway, as they say, life goes on. I finally got around to buying a new calculator! After writing many words on the subject I finally put my hand in my pocket and bought an HP-35S. I could write an in-depth review about what it does and doesn't do. I don't think I need to though, all I can say is that I wish I had bought one long ago. It doesn't have some of the facilities my old HP-28S has, but in all honesty I can't see myself performing matrix operations on a pocket calculator now. The HP-35S actually looks and feels like an engineering tool rather than a toy. It has enough of the old-school look and feel without being an antique. Perfect.

Part of me still wants a true old-school looking calculator with a nice fast ARM processor and OLED screen though...

So What About the LCR Meter?

A good question. The design has been through a couple of revisions since I last wrote about it. Expanding the current and voltage range of the AD chip I was using has proven quite effective but rather complicated to execute. 

A thought struck me - if I were designing this on a clean sheet of paper, what would I do? After thinking about it, I have gone back to the drawing board. Rather than hack stuff onto the AD5933, how about using an FPGA, with separate ADC and DAC? That would allow me to generate higher resolution, allow me much better control over the signal generation and analysis, plus it would allow me to configure it as an arbitrary signal generator, plus audio spectrum analyser. If you are going to do feature creep, do it properly!

6.002X version 2, and MITx: 6.00x Introduction to Computer Science and Programming

6.002x Revisited (Briefly)

My review of MIT's 6.002X electronics course seems to have been well received, and the lectures are is now part-way through their second run-through. I was disappointed to see that not much has changed. The videos are still of generally poor quality and slightly confused.

There is one change of note though. You may remember that one of my criticisms was in the area of answer entry. You often had to type in a horrible sequence of variables on a single line, which may or may not have resembled your answer. Getting a red cross meant you had to try again, not knowing whether your answer was wrong, or just your data entry. I suggested that the LaTeX formatting engine used in the questions could be used, to display your answer in a clearer format. I am pleased to say they have done exactly that!

Answers are now converted on-the-fly to a much clearer mathematical expression on the screen. Excellent stuff, and a big green tick for that!

MITx: 6.00x Introduction to Computer Science and Programming

It is now a couple of decades since I formally studied Computer Science, so I thought I would stick my head around the metaphorical lecture room door and see what has changed. To be fair, 6.00x has only been running a day, but there are some points worthy of comment. The 6.002x people should sit up and take note.

Firstly, technical quality. Rather than use a disembodied voice, we get to see the lecturer close-up on screen, with a microphone close by. On some of the videos I saw, the audio bit-rate was highly variable; some were 192kbit/s quality, others were closer to 32kbit/s. For the most part though, he is clearly audible and his presentation has been tailored to a single viewer rather than a full lecture theatre.

Secondly, the diagrams and so on have been prepared beforehand and are of a very good standard. Unlike the scruffy hand-drawn notes in 6.002x. Using these pre-drawn diagrams probably saves 10-15% of lecture time alone, and smooths the lecture's flow in general.

One particularly nice touch is the mention of Alan Turing's name. A man who is increasingly seen as the father of computer science, and whose name has been comparatively unknown for too long.

So far so good, I think I will stick with this one and get to grips with Python.I doubt it will take over from C in my toolkit any time soon, but it is certainly gaining in popularity.

The London Underground Map - as a PCB?

http://london-underground.blogspot.co.uk/2012/09/the-tube-map-as-radio-circuit-board.html



How brilliant is that! A working radio, laid out as a real tube map. I bet the stray capacitance is an absolute swine though.

The designer of the original tube map, an engineering draftsman named Harry Beck, is widely thought to have based the classic London Underground tube map on electric circuit diagrams. Wiki disagrees, but he was an engineering draftsman, so must have been at least been heavily influenced by wiring schematics.

The same designer has also done this. Not quite sure what to make of it: http://www.designboom.com/weblog/cat/16/view/23447/yuri-suzuki-technology-will-save-us-denki-puzzle.html

MIT 6.002x Circuits & Electronics: Tries Hard, Could Do Better.

I hope this goes some way to explaining where I have been for the last few months.

MIT 6.002x Circuits and Electronics

6.002X is the online version of the respected Massachusetts Institute of Technology course 6.002 “Circuits and Electronics”. It has just completed its first run-through, and I have been one of the first "guinea pig" students taking it.

Full Term Report.

When I was at school, like most children I used to get regular school reports sent home to my parents. The first page consisted of “advice to both parents and teachers” informing them that vague and unhelpful clichés such as “could do better” or “tries hard” should be not be used and that parents should be given more useful comments. After working my socks off and (I thought) doing really rather well in my class, this eleven year-old’s very first term’s report said:

                                "Tries hard, could do better."

As you will see, it seems appropriate for this course. However, in an attempt to be less vague and unhelpful, I decided that a blog was probably the best way to get my opinions and ideas across. 

Kindergarten

I think I need to offer some context here. My first Degree is not purely in electronics, but is shared with software engineering and system development. Despite finding the systems and software aspects both interesting and useful in my career, as time has gone on I have regretted not having a deeper understanding of “pure” electronics, but there is only so much you can fit into 4 years study. So, when the esteemed M.I.T. announced that it was making one of their electronics courses available as “Open Courseware” then it seemed the perfect match for my needs. A good time to brush up on forgotten facts, and learn some new ones too.

I had already watched most of the recorded 6.002 “live”(i.e. recorded in a lecture theatre) lectures on YouTube and they seemed okay. No better than that though, and certainly not up to the quality of WalterLewin’s  MITphysics lectures. Given the prestigious name of the institution and their reputation for ground-breaking methods developed in the Media Lab, my expectation was that, as part of the transition to on-line delivery, they would have taken time to prepare a clear and thorough presentation of the subject, taking academic lectures to a whole new level.

Open Courseware is Nothing New!

Here in the UK, we have an institution called The Open University. It was founded by the government in 1969 as "the university of the air" with the aim of making high quality higher education available to everyone. One of the unique aspects of the O.U. was the use of broadcast television in order to distribute lectures – remember that in the 1960s and 70s virtually nobody had a video recorder.

Sadly, as time went on, the O.U. realised it could distribute lectures on VHS cassette, then DVD, with the result that by 2000 virtually no academic programmes were being broadcast on free-to-air, just the “fluffy” populist programmes with little academic rigour. I would really like to see the O.U.'s back-catalogue of lectures available free on YouTube or similar service. The technical quality may not be great (heck, many of them are in black and white) but the content is exceptional.

I may be an engineer by profession, but I grew up in the 70s, 80s (and 90s) watching low budget but well designed programmes, not just ones on physics and mathematics, but history, chemistry, art, languages, literature… You get the idea. Lots of things. I didn’t understand all of it by any means, but I feel it made me a better person, and it instilled in me a hunger to learn. Free, high quality education changes lives for the better. Even, or perhaps especially, the less advantaged parts of the world.

If I seem critical of 6.002x in this report, then it is from a desire to see it work, and work well, and to foster the development of much more open courseware. I know what effect the O.U. had, and the thought of what MIT (together with Harvard, Stanford and the like) can achieve with MITx is one of the most exciting things I have seen in a long time. It really does need more work though. So, here we go. The criticism.

Presentation

Professor Agarwal is to be lauded for his work in making this course available to the entire world, and I think his enthusiasm makes him the ideal person to spearhead the open courseware movement. I have to be honest though, and admit that his presentation style is not ideal in this particular context. Note that I am not talking about his accent, although I can see how people whose first language is not English may well be confused.

When I was at university (which to my horror I have realised is now nearly 20 years ago and thus several generations in technology terms) the lecturers would often use pre-prepared overhead projector (OHP) slides with spaces to work through problems. This produced a nice linear work-flow which made it easy to write clear and effective notes. The slides themselves were also available later as photocopies for students who had been unable to attend the lecture. I found it worked very well indeed both for learning and revision. Think of it, if you will, as pre-written blackboards. The lecturer doesn't need to spend time writing things down, so you can get on with the business of actually learning.

The existing real-world 6.002 lectures take place in a multi-hundred seat lecture theatre, with a conventional blackboard (chalk-board to all the non-native English speakers). This retains some linearity but can get messy, and the lecturer spends a considerable amount of time simply s-l-o-w-l-y writing things down. A phrase which takes two seconds to say and understand can take ten seconds to write.

However, rather than repeat the existing video lectures, MIT have taken the decision to go with virtual slides; basically Dr Agarwal writing on a screen via a graphics tablet. As you can imagine, each slide can get rather cluttered and confused by the end of each lecture video. The flow, rather than being in a linear sequence, is all over the place and useless forrevision.

    

The move to a web-delivered format should, in theory, enable a more carefully crafted and controlled learning experience with a good flow and clear graphics and animations. Instead, we have the lecturer writing on a graphics tablet, over a tiny area. This is exactly the same content seen on the black/whiteboard in the live lectures. The tiny area makes things get cluttered very quickly indeed, and the thick “pen” used is rather unclear. The resultant image is crammed into 674x379 pixels, as you can see above.

I appreciate that using a small screen size allows lectures to be viewed on small hand-held devices, but it compromises the delivery of those lectures, and at this stage we should not be looking at the lowest common denominator but, instead, how current technologies might be used to improve the presentation.

I’m afraid the lectures have the feeling of “oh bugger, I forgot to prepare anything, I will do it as I go along”. You can get away with this in real lectures, but for video presentation then I’m afraid it isn’t good enough.

The very first presentation I gave in front of an audience at university was hacked together in a couple of hours the night before, and I hand-wrote many of the slides as I went along. I got a C grade for doing enough, but the other students showed me that I should have prepared far better than I had. These lectures have a similar feel to mine.

With all the resources of MIT, it must surely be possible for someone to digest these lectures and present them in the form of mostly pre-made slides? Some of the slides we see are partly pre-drawn, but get cluttered very quickly (see above) and Prof. Agarwal has a habit of adding unnecessary “fluff” and comments.

The original 6.002 lectures are recorded in a live lecture theatre, the sound is generally crisp and consistent. I wish I could say the same for the 6.002x version. Not only is the sound frequently muffled and masked with rustling, but the audio levels vary massively, even within one 5-minute video. It is clear that they weren't being monitored during recording, or even reviewed afterwards.

(Not) Recorded In Front of A Live Audience

I have just been watching an interview with the instructors ( https://6002x.mitx.mit.edu/section/instructor_interview/ ) and they raise some relevant points which are largely unanswered among the “didn’t we do well” mutual back-slapping. The main one is the important role that feedback plays in lectures. Students point out mistakes, and a puzzled expression on several faces can tell the instructor that their explanation is unclear, and thus should perhaps be trying an alternative approach. This is never going to happen when recording in a booth with a monitor and graphics tablet for company.

I'm afraid that Prof Agarwal gets into the habit of repeating himself quite a lot. By the final lectures he was saying the same thing as many as four times. This is annoying, wastes time, and breaks up the train of thought. It could (and should) have been edited out. Recaps at the start of every section just aren't needed when the student can click a button and see the previous sub-lecture. When you are watching a sequence of lectures, it gets really irritating to have a recap every 5 to 10 minutes.

Rate of Delivery

In the official introduction, we are told that we should be spending around ten hours a week on 6.002x, including lectures, tutorials, lab work and homework. To do justice to the subject, ten hours is probably somewhat on the low side, especially if you are returning to formal education after years away and need to do some catch-up work on the maths or whatever (remember: you can't pause the course to revise another subject). At over 1000 pages, the course text book would take well over 10 hours a week to complete, even if you were only doing a few of the exercises.

That doesn’t seem too bad does it, ten hours in a whole week. Let me put it another way though. That is 25% of a full time job, or 1.5 hours every day.  Let us assume that we are unable to study one day. This means that we need to find three hours study time the next day in order to catch up. Sadly, real world events happen and these hours mount up, and it is horribly easy to get left behind. The chain nature of the subject means that it is difficult to cut your losses and start a new subject. The result is that it becomes impossible to catch up. Unfortunately, this is what happened to me when a family member became ill. This is always going to happen in the "real" world, more so than among a group of full-time students without young (or elderly) families to look after.

Rather than having two lectures per week and running for 13 weeks, I would run it at half that speed. Better still, why not have it on-demand? If the need for regular testing is removed (see later in this blog post) then I see no reason why a student could not progress at their own rate, and do full justice to the subject, instead of having to gloss over parts because of time restrictions. Mid- and end-of-term testing could still happen at fixed quarterly intervals, with the student undertaking them only when they felt confident to do so.

Testing, Testing, 1... 2...

Currently, testing is in two formats. Firstly, each week has a set homework which must be completed within 2 weeks of being set. Labs are effectively a second homework, with the same issue and completion dates.  So far as I can see, there little policing of homework answers on the official forum, and other web sites also contain discussion about homework, with extensive worked answers for most of the questions.

It is perfectly possible for a student with no electrical knowledge (but a whizz on Google) to be able to find the homework answers and copy them over. In fact, most discussion seems to be along the lines of “I need the answer to Hw7 Question 3”. The on-line chatter about 6.002x definitely has the emphasis on passing tests rather than understanding the subject. I am aware that there are groups of students out there who share sets of answers. The result of this is going to be a set of students who know nothing about engineering but who have an A grade in an MIT course. This utterly devalues the brand, and is something MIT need to be aware of.

I think running the course asynchronously would help reduce this reliance on copying, but I am afraid that it is going to be endemic in any system like this, which relies on automated pattern matching rather than a human being interpreting the submission.

I guess I was spoiled as a student. The emphasis was very much on understanding how to solve problems. So, if you got the numerical result incorrect, or made a mistake in one step along the way, you would still get the majority of the marks. An engineer is someone who can tell you why something works, and this testing system just doesn’t support that ethos. All it wants is a number, or a line of preformatted mathematical text.

Talking of which, the method of submitting expressions is horrible. The question setters do their best to allow for some flexibility, but the software cannot take individual style into account when checking an answer, whereas a human would not see it as an issue at all. I think it was week 5 or 6, which involved extracting MOSFET parameters via calculus. This resulted in a horrendously complex expression entered as a line of text, which I must have tried to enter a couple of dozen times before giving up (my calculation was actually correct). The LaTeX mark-up language is supported in the labs, I don't see why the homework system shouldn't support it too. Ideally the student could write the answer (and intermediate steps) in longhand on paper, but this would obviously not be machine-readable.

I noticed an excellent article on the BBC Education site concerning this issue. MITx (and EDx) seem to be looking at a form of peer-evaluation. This is an excellent idea if correctly carried out. Quite how they are going to trust a set of random (and inherently uneducated and inexperienced) individuals to score a paper, I am not quite sure. It definitely has potential though.

Because of commitments, I was unable to take either examination. I have heard several comments that people were surprised how easy it was in comparison to previously published examples.

Labs

All labs are based around a simplified web-embedded PSPICE client. This is good so far as it goes, but I was disappointed that an engineering course lab didn’t have a physical aspect to it. I understand that this would incur a potential cost on the part of the students, but I believe this could be done inexpensively with a cheap breadboard and a small collection of components. It need not be compulsory, but I am sure many students would welcome the opportunity to understand electronics at a more physical level.

Either way, I would love to see more labs, whether virtual or physical. Getting a real feel for how components work is vital for any engineer. Just knowing that an Amp or a Volt is “so much” and “that much makes a wire melt”. Too many paper engineers don’t have this sense of what is real.

Tutorials

Each weeks' lectures are accompanied by a small number of recorded video tutorials. These may cover content from the lectures, or related skills such as soldering. (Memo to Americans recording electronics videos: You know how you laugh when we call a cigarette a fag? Well we do the same when you pronounce soldering as soddering)

More tutorials please! These are the strongest part of the course at the moment. If you want to see how they might be improved, go and watch some of Dave Jones' EEVBlog tutorial videos on YouTube.

Course Text

The course set text is “Foundations of Analog and Digital Electronic Circuits” by the lecturer (Anant Agarwal) and Jeffrey Lang . At 1008 pages it is certainly no lightweight book. It currently retails for £66 here in the UK, excluding postage (approximately £3). That is US$107. Yeah.

To be fair, the entire book has been scanned in and is available online on the 6.002x web site. You may be one of the fortunate souls who can read books online with no problem, sadly I am not one of those people, and printing 1008 pages doesn’t really appeal to me.

If the book weren't the official course text then I wouldn't look at it twice. There are many better books out there, which present the subject in a clearer and more methodical manner. I would go as far as to say that basing the course on this book is holding it back.

The Emperor’s New Clothes and Education by Omission

I have seen various comments on web forums concerning 6.002x. Inherently, many are from students who were, for one reason or another, unable to attend a “real” university. There is a certain amount of comment that the lectures only cover a small proportion of the subject content. Quite often, the response to their concerns it “it is MIT, one of the best engineering schools in the world, of course it is difficult” or “the lectures give you the basic tools, you are expected to do the rest”.

There is a certain amount of validity in this, where the student is physically within the learning environment. In this case, however, this approach simply isn't sufficient.Why not just buy the book and work through the tutorials? 6.002x is no longer a physical university course where students have multiple sources of support, and the existing lectures do not provide sufficient information.

A few weeks ago, I was watching the excellent “Ask AnEngineer” live Internet video programme, where (MIT alumnus) Limor Fried was talking to (fellow MIT alumnus) Amanda Wozniak. Someone asked what they thought of 6.002x. They both expressed surprise that MIT had chosen this particular module as the first to be trialled. Amanda said she had nearly abandoned the module half way through, as the maths was becoming overwhelming, and she was really struggling. I have to say that I have a lot of respect for Amanda as an engineer, she really knows her beans, and if she was struggling then heaven help the rest of us.The maths rather overwhelmed me at the same point.

You can call stuff “a bunch of fun” as much as you like (and Prof Agarwal never shies away from doing so) but hard work is hard work and should be treated as such. If a student thinks they should be enjoying it and are simply finding it impossible, then they may well quit. Engineering is hard. Sure, it can be presented well, and explained from various perspectives, but there is a lot to learn and no amount of "hey wow guys ain't this cool" is going to make it quick and easy.

So... Tries hard. Could do better. But How?

I am not egotistical enough to assume that MIT give a rat’s arse about my opinion, but I do think they will pay attention to the general consensus. I also think that if nobody says anything then they will assume the course as it stands is perfectly fine and will continue with it in the same format. It is a good start, for sure, but it isn't fine. 4/10 at most.

Overall structure.

• Remove the examinations (for reasons of mass-cheating mentioned above). Without having a real physically moderated examination, where the student is required to attend a controlled environment, I think they are ineffective and serve only to devalue the course, and MIT’s qualifications as a whole.

• This can be balanced by having more coursework. The only “qualification” on offer should be a certificate stating that the student has attended all the lectures and passed the homeworks.

• Crucially: Deliver the course flexibly and on-demand, with no time limits. Allow the student to start when they want and to progress at their own speed.

• More of the excellent tutorials.

Technical quality must improve vastly.

Let me state at the start; Budget is no excuse for poor quality.

The audio must be clearer and more consistent in volume. If MIT’s broadcast facility won’t allow you to use their equipment then inexpensive semi-pro equipment such as the $100 Samson C01U studio microphone is excellent quality. Software such as Audacity allows the levels to be normalised within seconds at the click of a mouse. This is supposed to be professional. If the quality isn’t good enough then re-record it! Choose a good bit-rate too, there is some awful compression distortion on some parts.

I won't even call the existing quality amateurish. If anyone at MIT wants to see how good lectures and teaching sessions can be, then please look around YouTube.

The method of using a graphics tablet to write on the screen is horrible. Worse in terms of readability than the live lectures, and very wasteful of time. Pre-prepare a full set of clear slides at a good resolution. Having written a book on this subject, a set of slides should not be difficult. Yes, this takes time and effort. If you want to give a quality educational course and don't want to do the work, then let someone else do it instead. In the spirit of Open-ness I am almost inclined to make a set of animated slides myself, just to show what can be done even with my mediocre skill in presentations.

If need be – script it! This is basically a broadcast TV show now. Ums, errs, aaaahs and repetitions are utterly unprofessional. Absolutely fine in lectures, but not in this context.

Avoid clichés like the plague (yes I really did say that). Avoid calling things “a bunch of fun” or “exciting”. Interesting maybe, but not fun. Remember you are talking (partly) to teenagers who have recently discovered alcohol, sex and really loud music. Possibly even all three at the same time. Is power rail bounce or signal reflection really fun? I'm not getting all Puritan here, it just really annoys me when someone tries to hype something up which is clearly rather dull.

UK people will know what I mean when I say it gets a bit happy-clappy vicar with a guitar and tambourine. the more you try to "get down with the kids" the further away you push them.

The book. It needs to be available in print form for under £30. There are on-demand print services (not to mention dubious sources in China and India) who will print it for a fraction of that, if the will is there from MIT and the authors.

There is content missing or lacking in detail, and content which could more logically be located in a subsequent course. (For instance: What happened to bipolar transistors?) This must be the only course I know of which teaches active components before passives. I don't buy the "because it is MIT then it must be right". My alma-mater has Nobel prizes too, and they don't teach electronics in this rather muddled order.

Edit and edit again! Edit the script. Edit the videos and audio.The final few lectures on power rail bounce and signal reflection could have been edited down to 75% of the time or less, with no loss of content. At one point, Prof Agarwal said the same thing four times. Yes four times. He said the same thing four times. Isn't it bloody irritating and a waste of time when someone says the same thing four times?

Conclusion

All good experiment write-ups should have a conclusion, so here we are.

• Was it worth my time? Yes, definitely.
• Would I do it again? Not unless the video lecture content is massively improved.
• Would I do another similar online academic course? Unreservedly yes.
• Would I recommend it to someone looking to study electronics? Maybe. I suspect it would put a lot of people off serious engineering.

I really enjoyed getting my brain working again, remembering long forgotten facts and learning a lot of new stuff. I also learned that I have forgotten a huge amount of maths. It did soak up a huge amount of my spare time though, and only part of that was watching the videos and working on the assignments.

With the introduction of edX, which will effectively be covering all the MITx content now, and the promotion of Prof Agarwal, I suspect 6.002x may well change before the next offering. Hopefully this bringing-together of skills and services will raise the quality of content and delivery.

With such big names getting serious about Open Courseware, this entire field is going to get very big indeed.On a human scale, it is going to have a huge impact. Possibly even bigger than people yet realise.

R.I.P. LCD. Hello OLED?

Organic LED (OLED) technology is one of those things that seems to have been on the way for years. It was going to replace LCD tech at a sweep, with ultra sharp, high contrast goodness. Like many such things, it never managed to take the world by storm, but it still has it's own advantages and disadvantages. I have kept meaning to investigate OLEDs for a while so (with one eye on the LCR meter project) I finally got my finger out and blagged a Densitron DD-12864YO-3A from Farnell Element-14.

Yeah, memorable name. You might guess though, that it is 128x64 pixels, and (monochrome) yellow. I'm used to conventional LCD modules, where a 128x64 might be 100x50mm (4in x 2in) and I had read the data sheet, but I don't think I was ready for quite how small this wee beastie is:

This instantly raises an issue over the form factor. I guess it is technology intended for mobile phones, but for practical hand held test gear I think it is just a bit too small. You can get 256x64 units which are approximately twice the width, but they are twice the price too, and well into the territory of colour LCD with integrated touch panel.

I had intended to hack this straight into an Arduino or Mbed, and get a quick demo running, but a few things have stopped me. See that connector in the photo above? 24 pins, each half a millimetre apart - clearly influenced by it's mobile phone background. None of this standard 0.1" header LCD here! Even with the matching socket, it really needs a custom PCB to break out the lines. Fear not though, I have a cunning plan, which involves a load of 30AWG (0.4mm) Kynar wire.This alone is going to slow down take-up when it comes to amateur projects and even professional prototyping. Secondly, though, the module is 3.3V only. No 5V here, no sir. A few resistors should sort that problem out, but it all adds up. Having said that, I don't know of any commercial systems that run 5V any more, so it is no big issue for non-Arduino folks.

One part of the manufacturer's data informs me that I need an externally generated 12V supply, but another part tells me that it can be generated internally. We shall see.

Looking at the pinouts, it seems like it is an adaptation of the classic HD44780 chip. It isn't. It uses an SSD1305 which does waaaay more than the old chip. Unfortunately this means it takes a lot more driving too. Just booting it up takes a fairly hefty code sequence. The user can elect (by variously grounding 2 pins) to use a classic 8bit 68xx or 80xx parallel protocol or, more interestingly, use 4-wire SPI or 2-wire I2C. If the manufacturers had desired, they could have easily halved the pin-count by going serial only, and removing three "No connection" pins that they insist should be grounded. I'm sure the market for breakout boards with a boost power supply and a level converter is already out there.

So, this looks like an interesting little adventure. I can think of a few projects where a module like this would be useful, not least my JTAG adaptor. It is definitely the sort of thing I will bear in mind for future designs, possibly filling in for indicator LEDs rather than low current LCD (the OLED unit draws up to 55mA). I hope to have some shots of a demo up soon.

Thanks go out to Farnell Element-14 for supplying the Densitron DD-12864YO-3A.

Arduino - DIY Electronics for the 21st Century?

Over the past year or two, it has felt like you can't turn a page in a tech magazine, or read a web page about electronics without some reference to the Arduino. Somehow it seems to have moved from serious "difficult" electronics, into an everyday commodity.

Thus far, I had resisted the Arduino's allure. I don't have any experience with Atmega processors, my usual preference is for one of the Microchip PIC families or, if more power is needed, an ARM cored device. But how could I give an opinion without owning one and having a play around with it? I was impatient as usual, and the people at Farnell / Element-14 had one sitting on my desk within 24 hours. Excellent.

The Arduino Uno

I will go into more details later, but here is a quick rundown.

The Arduino Uno is a totally open source embedded development board, based around the Atmel Atmega328. Other "flavours" of Arduino are available, usually based around other Atmega chips. Arduino isn't just limited to the hardware, however. It also covers the development environment which, to my mind, is the crucial factor in it's success.

The Arduino Development Environment
(Click for larger image)

As you can see from the screen grab above, this isn't Microsoft Visual Studio. Thank goodness. Simple and clean with syntax highlighting. This is why Arduino has taken off.

The Uno itself measures just 53x69mm, and arrives in a simple cardboard box that looks more like a packet of cigarettes or condoms. No. Really. The accompanying leaflet covers the usual legal disclaimers and little more. It would be nice if it said "Congratulations on your new Arduino, now download your free development software from www.arduino.cc" or similar.

It is powered via the standard USB "B" socket, or via a jack socket. I find it odd that they haven't moved over to a mini or micro USB, but no great shakes. The general standard of construction is solid, as you might expect with a mature product, the CPU being a socketed 28-pin DIP/DIL device. This is so you can remove it after programming, or plug it into a breadboard. Or, I suppose, replace it if you toast it.

There is a HUGE amount of resources for the Arduino around the Internet. Almost too many. If you are interested in seeing what it can do, and how easy it is to use, then I recommend Jeremy Blum's YouTube series here.

I got mine from Farnell / Element-14, who stock a range of Arduinos and related gear.

The Arduino Uno I reviewed is available here http://uk.farnell.com/arduino/a000046/board-arduino-uno/dp/1848687

Arduino's home is at arduino.cc

John's Tronix Stuff tutorials here.


Additional: If anyone has any good Arduino tutorial sites they would like me to add, simply add a comment or drop me a line.

Tektronix DMM4020 Bench-top Digital Multi Meter - First Impressions

This is an initial overview of the Tektronix DMM4020  Bench-top Digital Multimeter.

This overview was originally written for Element-14 and is available here. 

http://uk.farnell.com/tektronix/dmm4020/multimeter-bench-5-5-digits/dp/1771901

http://www.tek.com/products/digital-multimeter/dmm4020/

Unit Price:    £528.00  

I must stress that this is just an initial overview.  The DMM4020  is very much a professional piece of test equipment and needs to be used properly in a work context for some time before I can give a thorough in-depth review. Nevertheless, in the short time that I have had it, I have already learned more than enough to give a good overview.

A few month ago, I had considered that a good bench meter should really go on my list of test gear. Less than a week after its arrival, I wonder how on earth I managed without one. After all, hand-held multimeters are really good now and - it has to be said - more than good enough for most work. So why has a bench meter already earned its place in my lab?  Read on…

The meter arrived in sturdy double-layer manufacturer’s box measuring 9”x12”x17”. Inside is a pair of vacuum formed foam blocks which sandwich the meter and provided good impact protection on its journey here. It is the sort of packaging that is worth keeping for storage, should you need to move it around or keep it safe.

Unless you have a huge bench or a permanent place in a rack, then this meter does take up quite a bit of space, being 9 inches wide and 13 inches front-to-back (although it is tiny in comparison to the high end calibration lab stuff). Traditionally though, bench gear like this does appreciate being left switched on permanently, to allow the temperatures to stabilise, minimise thermal cycles and prevent any moisture affecting components as the lab cools down over night. Unfortunately the DMM4020  has a fluorescent display, which has a tendency to fade when left on for extended periods (years). I have not yet discovered a way to turn the display off whilst keeping the electronics running. There is a “soft” power button on the front panel which may well perform a similar function. That is definitely something to investigate. Otherwise, though, the VFD is bright, sharp and fast to react, probably better than LCD could give.

However, this is jumping ahead slightly. The very first thing that I saw – a printed manual. Yes folks, real paper, with print on it. Spiral bound. Hallelujah! Only 26 pages of it are in English (the rest is Japanese and Chinese). It is only a “Safety And Installation” Manual, but it covers the main functions and accuracy tables. The full User Manual is 110 pages but unfortunately only available in PDF format. I will go more into the contents of this manual in the full review. The S&I manual states that power consumption averages  10 Watts, with a maximum of 15 Watts. Each side of the case is  plentifully supplied with ventilation holes, and having left the DMM4020   on for 6 hours, the temperature stabilised just above ambient. It runs  very cool indeed for mains powered gear.

Caution!

There are two things to watch out for before you start. Most importantly, the DMM4020  uses a conventional transformer power supply which is supplied configured for 110V.

It takes until page 10 of the Installation Guide before it mentions line voltage selection. I imagine almost all users will know to check this first, but in a world where people are increasingly used to switched mode power supplies that take 100-240V without configuration, a caution sticker would probably be wise. The actual method of voltage selection is a bit odd but nevertheless functional; You unclip and remove a module which has the mains fuse and a plastic “spider” inside, which is rotated to suit 100, 120, 220 or 240V and re-inserted. Despite having a mains transformer, the unit only weighs a modest 2.1kg

Secondly, the supplied mains cable has a US standard plug. This is not a problem though, as the connector is a standard IEC “kettle lead” and most labs have plenty of those hanging around! The DMM4020  does have a set of stand-off feet moulded into the rear of the case, which allows it to be operated vertically rather than in the conventional horizontal manner.  Unfortunately the supplied mains lead is a “straight through” rather than a 90 degree elbow, and so if you try to stand the meter upright, whether against the floor, desk or slotted into a rack, it sits on the cable rather than the feet, and so is unstable. Note to Tektronix : Supply a 90 degree "Elbow" power lead please!

One thing which is really good to see – a proper mains on/off switch mounted next to the power connector. So far as I can see from looking through the ventilation holes, this is a proper switch which isolates all internal components.

Construction

As you can see from the photo, the DM4020 comes in Tektronix corporate colour. That familiar grey-blue colour which is so often seen around labs. The main body is pressed alloy construction, with plastic front panel. The front and rear both have flexible plastic/rubber protective “boots” which can be removed for rack mounting. As usual with this sort of equipment, there is a tilting bail which can be positioned in a number of angles, used as a carrying handle, or removed entirely. The HRC fuses are of the high quality you would expect, and are accessible by removing a small metal panel underneath the unit. A small plastic box covers the fuses themselves, presumably for insulation and blast containment.  They don’t seem as well protected as they are in hand-held meters.

Internally

I don’t intend to take the DMM4020  apart, not least because that would entail breaking the calibration seals, which I am loathe to do. Fortunately, however, you can get a pretty good view of the insides just by looking through the ventilation slots. This is very much a unit for a clean lab and not a dusty shop floor which would risk contaminating the sensitive electronics in no time.

Visible in the middle off the board is the heated precision voltage reference, clearly labelled LM399H with a National Semiconductor logo. A well known and well respected precision voltage source, used in several meters in this market segment.  Interesting that they didn’t choose an LM199 or LM299 which seem to be 2% initial tolerance versus the LM399’s 5%, although it has to be said that after calibration there is little difference. I suspect that putting the unit into standby from the front panel will keep the heater running inside the voltage reference whilst powering down the display and processor. This would seem an ideal compromise.

In use.

As you can see from the front panel, the Tektronix DMM4020  is a 5 ½ digit unit, with separate connections for low (200mA) and high current (10A) ranges. It is also capable of full 4-wire resistance measurement, although only a pair of Tek TL710 conventional probes are supplied. Supplied probes are usually low budget affairs, but these are really nice sharp Cat III/Cat IV 10A probes with finger shields. However - no ground clip is provided! This is definitely an oversight in a meter of this stature.

One feature I will certainly be looking at is the ability to take two measurements at the same time, or sequentially. Some meters can perform functions such as AC voltage + Frequency, but not many can perform current + voltage measurements together, or DC+AC, such as might be used to monitor power supply ripple.

You will note that it does not measure inductance or capacitance. I guess at this end of the market you would be expected to purchase a separate LCR meter.

Performance

These are the easiest to quantify in hard numbers. All this data is copied from the official (copious) Tektronix information, boiled down into the main points. I will go into more depth in the main review:

Measurement Speed

The DMM2040 can measure at 2.5, 20 or 100 samples per second. Normally 2.5 is perfectly sufficient, and 20 cannot be distinguished by human eye. However, this is good for capturing short transition events, or for high speed logging via the computer link. In the faster two modes, however, precision is truncated by one digit.

DC Voltage

Maximum input: 1000V
Input bias current: <30pA @ 25C
Input impedance: >10G Ohms (200mV and 2V ranges)  10M Ohms (20/200/1000V ranges)
Resolution on 200mV scale: 1uV
Accuracy:    +0.01% of reading + 0.003% of range

 

AC Voltage (True RMS)

Maximum input: 1000V peak, 750V RMS.
Accuracy (all ranges 45Hz – 20kHz): 0.15% of reading + 0.05% of range

 

DC Current

Input protection: 11A/1000V and 440mA/1000V fuses

Shunt resistance: 0.01 Ohms (2A and 10A ranges)
                           1 Ohm (20mA and 200mA)

Resolution:         200uA scale: 1nA (yes, that’s 1 nanoAmp)

Accuracy:           typ. 2mA scale 0.015% of reading + 0.005% of range

 

AC Current:

AC Filter Bandwidth: 20Hz – 100kHz
Maximum Crest Factor 3:1 at full scale
Resolution:  20mA scale: 0.1uA (100nA)

Accuracy:  Typ. 200mA scale, 45Hz-2kHz: 0.25% of reading + 0.05% of range.

 

Resistance

Specification for 4-wire function or 2-wire with REL (relative measurement)
Input protection: 1000V on all ranges
Resolution:         200 Ohm scale :  0.001 Ohm (1 milli-Ohm)

Frequency:

Range: 20Hz – 1MHz, for input >100mV
Accuracy: 0.01%

Continuity:

Threshold: 20 Ohms
Test current: 1mA

Unseen performance

So much for the book data. With less than a week’s use, it is safe to say that I haven’t even scratched the surface on what the DMM4020  can do, but I have found some very nice functionality that most users just wouldn’t notice unless they were looking for. Specifically:

Diode test.

Most diode test functions only work at 1-1.5V, enough to test ordinary signal diodes, but not enough to test LEDs. The DMM4020  reads up to 1.9999V and drives up to 0.8mA, sufficient for the LED to light quite brightly. In theory this is only enough for red /yellow/green LEDs, but in practise the unit will illuminate blue and white LEDs also, which I was not expecting, although it will not give a voltage measurement for these.

Zero-burden Microammeter.

Most engineers will be aware that the usual way of measuring current is to insert a small resistance into the circuit and measure the voltage drop across it. At low currents this can be quite a high resistance, leading to a “burden” voltage drop which is unacceptable and may even upset the circuit under test.

The correct way to do this is with a transimpedance amplifier which provides almost no voltage drop, but can only realistically be performed at low current levels. It is quite a complicated thing to get right in a design and, as a result, is only usually seen in expensive dedicated microammeters. The Tektronix DM4020 is the only meter that I know of (this side of £1000 anyway)  which uses this preferred method for measurement. If you often measure low currents, this feature alone may be worth the price of the meter.

Relay Range Switching.

In order to switch in appropriate shunts and multipliers, the DMM4020  uses proper electromechanical relays rather than silicon switches. This slows down auto ranging, but not unacceptably so. Manual override is always available and is probably preferred in most cases. Relay switching is by far the best method in equipment where you are looking for measurement performance and have the luxury of a large PCB real estate and a mains power supply.

“Other Stuff”

The supplied LabView software is a little clunky to install (and partially deactivates after a preview period) but does work pretty well. I am no LabView expert, but I can see how relatively easy it is to automate tasks if you are working in a production environment. This is definitely one thing I will be looking more closely at. Simply logging data in ASCII format to a text file is very handy indeed.

In order to connect the DMM4020  to the outside world, it is fitted with a standard RS232 port at the rear. Tektronix thoughtfully provide an RS232-to-USB adaptor, with a good 2M of cable. This seems to be based on an FTDI chip, which in my experience has proven most reliable in this sort of role. Windows 7 picked it up straight away and downloaded drivers via Windows Update.

Conclusion

So there we are. Four days use and a “quick” look that is already several pages long. That gives you an idea about what sort of machine the Tektronix DMM4020  is, I hope that I have at least been able to give a taste of what this machine can do. I hope to have a much more in-depth review up in a few weeks, after it has had some use in a real world situation. One of the things I have lined up is the development of my LCR meter project. Having a meter this accurate will help immensely.

A Request

I want to shoot some video of the DMM4020  in action if I can. At the moment I only have a webcam and a cheap compact camera that will shoot video, so I am looking to buy myself a reasonable 720 or 1080 digital video camera. Does anyone have any recommendations? I don’t want to spend more than maybe £150 or so, it doesn’t need to be a fantastic spec. Thanks!

Additional: Farnell / Element-14 tell me that UK purchasers will have their meter pre-configured for UK 240V power.

HP-15C now in Stock at HP! No it isn't! Yes it is ! No it isn't!

Well, the HP-15C finally made it to market, and promptly sold out within a few hours. So quickly, in fact, that I didn't even get a chance to post it here before they had all gone. From the look of Ebay, many seem to be bought by speculators.

Anyway, they are back on sale at HP's online store. Oh wait... No they aren't. This time the stock lasted about half a day. All I can say is - keep an eye out for when they restock! My guess is that if they keep selling this quickly, then the Limited Edition won't be quite so limited.

Amazon.com look to have them in stock. 4 left at the time of writing, listed at a mere $119:99. $20 more than the official HP shop, albeit Amazon have free shipping. Can we say "gouging"? I thought so. Still, it is cheaper than Ebay.

I don't think I will be buying one, I find the missing binary / hex modes too useful. Any chance of the HP-16C? Potential purchasers might like to be aware that the build quality is typical Kinpo Electronics rather than classic Hewlett Packard.

A PCB CAD Refresher Course

At one time it felt like I was destined to be a PCB designer, churning out design after design for someone else's work. Now this is a very worthwhile and skilled job, but it wasn't for me, and so it is only occasionally that I get to design PCBs now. Unfortunately that means that I tend to forget work-flows, and fiddly little quirks and details. Come to think of it, I tend to forget some pretty big details too! When you have let muscle memory get on with things, it can be daunting when you come back to your CAD software.

I have a fair few notes which I have written up over the years, and I was even considering recording a video. This started me wondering what YouTube might have to offer. Altium have done a load of videos (hosted on their own site), but I have to say they aren't very helpful. At best they are rather "corporate". Anyway, to cut a long story short, I found these YouTube videos. They are clearly recorded by someone who knows what he is doing, and aimed at the more introductory end, but are very much worth watching if you need a quick refresher.


All these videos relate to Altium Designer, and are best viewed full screen. Videos recorded by http://www.youtube.com/user/elektroniskorg

1. Schematic capture and PCB layout (Part 1)

2.Schematic capture and PCB layout (Part 2)

3. Creating a Component Library

 
4. Navigating Designs

5. Working with Vias and Multiple Layers

6. Copper Planes and Pours

Advanced Calculations

(Or how 1989 - 2011 = 15+30+34+41 )

Thanks to Make Magazine Blog for mentioning my article on calculators (see Difficult Calculations ). It seems that I am not alone in my calculator geekery. Page views shot up by a factor of 100x in a couple of hours!

Inevitably though, no sooner had I written the article than things started to move on. It looks like Hewlett Packard aren't totally devoid of sense after all. Thanks to Dave Jones of the EEVBlog for pointing me in the direction of this:

Yes, this is from the real Hewlett Packard web site. This is a screenshot of the Google cache (see here) of HP's Singapore web site. (Screenshotted just in case the cache gets overwritten) Similar pages were on other nations HP sites too, including the Indian version. I checked, and it all looks legitimate and not a spoof. At the time of writing, HP still hosts a photograph of the calculator in question, an HP-15C:

HP-15C Limited Edition

Investigations by the forum members at the HP Museum site have revealed that the "HP-15C Limited Edition" will shortly be on sale in Japan. No information is available as to whether they will be shipping them in other countries.If they do appear in the UK, then one is going straight on my shopping list.

It looks like a pretty close copy of the original, but the brushed aluminium bezel around the display has been replaced with what looks like white plastic, and the printing somehow looks less crisp. My guess is that Kinpo have been brought in once again by HP, and rather than simply producing a copy of the original, they have re-engineered it to maximise cost savings. Something which has rather back-fired on them in the past. As it stands, the (still in production) HP-12C internals have been converted to an ARM processor based system for some time, so a new version of the 15C and 16C should be straight forward.

Back in the 80s, the HP-15C cost $135. It looks like the new version will sell for an RRP of $129. That is fine in the US, the land of discounts and coupons, but I suspect it will come out at £129 here in the UK after taxes. Given that the HP-15C is based the same hardware used by the HP-12C ($70) then it starts to look a bit expensive. It is a shame that they didn't go the extra mile and produce the HP-16C too, which adds binary and hexadecimal functionality.

The WP-34S

It looks like the HP-12C re-purposing project (that's the polite term for hacking now) has stalled (see here) but the project to investigate the potential of the HP-20B and HP-30B business calculators seems to have moved onwards very quickly indeed (see here), enabling vastly more functionality, based around the HP-42S core software, but very much expanded upon. In fact, it does so much more, that the developers have had to print a whole new set of key legends:

Original HP-30b

Modified with WP-34SFirmware and key legends

Yes, these are the same calculator. I do wonder just how robust the stickers are, but reports seem generally favourable. A complete reprogrammed calculator + overlays is on sale at £76:98 / €84:68.  The firmware manual / user guide is available here.

Do you know what I love about it though? It has markings on the keys - and this is the important bit - I don't know what they all mean. Seriously, I have a row of letters after my name, I have been doing engineering maths for decades, but yet there is stuff in there that is a mystery to me. Sure, it is statistical stuff that I will never need, but that doesn't matter, it means someone is finally adding new functionality to calculators. It makes me feel a bit like when I was a kid with my nose pressed against the window of the glass cabinet with all those mystical electronic boxes inside.

So that is 15, 30, and 34 dealt with (see the blog title), how about 41?

Well, processor designer Monte J. Dalrymple has reverse engineered the HP-41C, and then created an improved version of it on an FPGA. I mean - seriously - it doesn't get much more hardcore than that does it?

Lots more information here on Monte's site. 

The thing is, all the essential hardware is on an FPGA. It is a relatively (and I use the term recklessly) easy job to hook up your own LCD and keypad, and you have your own HP-41C clone. All it needs is a millionaire willing to stump up enough money to make moulds for the enclosure. Some things have simply got to be done.

Suddenly, the world of calculators just got more interesting.

Hewlett-Packard Calculator Timeline

As part of my previous blog post on calculators, I had started to draw up a graphical representation of calculator evolution. My intention was to include TI, Sharp, Casio etc (hence the timeline starting at 1960) but considering this subset of HP calculators took several hours, I decided a full comparison probably wasn't worth the effort. Given the popularity of the previous item, I thought some people may be interested. It doesn't include all HP calculators by any means, finishing with the HP-48S.

Hewlett-Packard Calculator Timeline

Difficult Calculations

I suspect I was part of the first generation to have been brought up with “pocket” calculators (“pocket” to distinguish them from desktop mechanical calculators the size of a bread bin). I vaguely remember seeing them in my dad’s electronics magazines, sometime around 1979. One Christmas around then, my dad was bought one which has a fluorescent blue/green display which really looked super high-tech, and is still a really pleasing design. Although it was only a classic four-function machine (add, subtract, multiply, divide) I really coveted it, but it was couple of years before I got my own calc. 

Late 1970s Vintage LED Calculator
(Similar to mine)

I remember going to one of the electronics exhibitions that the magazines helped organise – possibly “Breadboard ’79” – where a stall was selling classic red-LED calculators for £2:99. Not only did it have the standard four functions, but a memory too. Wow, that was practically a computer! Other than the 7-segment, 8-digit display, the thing I remember most about it was the clicky keys. Noisy, but really good tactile feedback and, even on a super cheap calculator, it gave a feeling of confidence and precision. The 9V PP3 battery didn’t last more than maybe 10 hours, but it was long enough.

Of course the first thing I did when I got it home was to release the plastic moulded latches (no screws holding the case together) and take it apart. I was disappointed to find it had just one chip, and some convex metallic pads mounted directly on the PCB to act as switches. I felt ripped off that there weren’t half a dozen chips and proper switches, but it was all highly engineered compared with today’s products.

It was maybe a couple of years later, when I had moved up to the “big” school, that I discovered my form teacher had a programmable calculator. Woah! I had read about programmable calculators in magazines like PCW and Computing, and I had seen them locked away in glass cases in Boots in Leeds (for some reason Boots the chemist always had better calculators than the electronics stores of the time) but I had never seen one close up before. From what I remember, I think it must have been a Hewlett Packard HP-67, but I never got to see it again. The teacher had left it on charge at the back of the classroom over lunchtime, and some idiot had switched it off while the teacher was out of the room . She never (probably quite rightly) trusted us again.

Retro Calculator Sexiness
 The HP67 programmable

 Time moved on, and a year or so later I had saved up enough money to buy myself a Casio fx-3600p. Liquid crystal displays had pushed out the power-hungry LED machines, and my trusty Casio looks just like an average calculator you would buy today. Indeed it is only recently that Casio only stopped production of this model. Incredibly, it is still running on the same battery it came with. If I hadn’t experienced it personally, I would have said a 30-year battery life was impossible, but there you are. On the back it quotes “DC 3V 0.00043W”, something modern manufacturers still have trouble approaching today. The fx-3600p is programmable, but with only a 38 step memory and no alpha characters it’s programmability is rather limited to say the least.

As with many kids of the time I had a Casio CA-90 calculator watch (with a built in game that was surprisingly popular with the non-geeks at break times), and then a CFX-20 scientific calculator watch. Geeky? Hell yes. It even has a dot-matrix display which tells you what scientific or conversion function you have selected. Bloody good watch though, and I still have the slightly posher version, the chrome CFX-200. For some reason, I never particularly liked the styling of the CFX-40/CFX-400 which added potentially useful binary, octal and hexadecimal functions, but a cheap looking touch keypad.

1983 Casio CFX-200 Scientific Calculator Watch
(on my hairy wrist.)

Casio's later CFX-400 model with touch keypad.
Note the hex/octal/binary and logic functions.

 Sadly, that was the end of the line as far as calculator watches went. Casio decided to make “memory bank” and TV remote control watches instead. You can still get calculator watches of course, but they don’t even have the abilities I had in my 1983 scientific machine.

It would be remiss of me if I didn't mention at this point, Dave Jones' programmable scientific calculator watch design. I think Dave would be the first to admit it isn't exactly stylish fashion jewellery, but it is a phenomenal bit of work. It even plays a game of chess for goodness sake! Just imagine what Casio or Seiko could do with a bit of willpower and a million dollars or so.

Eventually I did my A-levels and decided that, for Uni, I deserved a better calculator and bought a fearsomely expensive and highly desirable Casio graphing calculator, the fx-7000g. So desirable that it lasted nearly 6 months before being nicked, and I went back to my fx-3600p. In all honesty, the fx-7000g wasn’t a great machine. Sure it did graphs, but then I know what graphs of sine waves, X^2 and so on look like anyway. I did get it to plot Mandelbrot and Julia set fractals, but that took forever, and a 1-bit greyscale can never do them justice. The huge screen just made it look clunky. In hindsight, this is where calculator design started to drive up a blind alley.

Casio fx-7000G Graphing Calculator

 

The temptation didn’t last long though, and a friend of mine had a Hewlett-Packard HP-28C. Properly programmable with a real programming language, small bitmapped display, alpha-numeric keys, hex/octal/binary, arrays, complex numbers and, most importantly, it had proper clicky keys and operated using the mystical Reverse Polish Notation – RPN. The absolute pinnacle of the calculator world. I spent a huge chunk of my first term’s grant on the 28C’s faster and more capacious offspring, the 28S. Thanks to the RPN, people only ever borrowed it once, and it never got stolen. It was worth every penny, HP had a track record of making well engineered calculators for people who use them every day. Calculators for engineers and scientists, not calculators for 14 year olds.

My Hewlett Packard HP-28S and Casio fx-3600P Programmable Calculators
(with obligatory schoolboy humour)

I still have both the fx-3600p and HP-28S, but more importantly though, I still regularly use them. The Casio needs it’s contacts cleaned once a year and the Hewlett Packard is also a pain because it uses three relatively expensive batteries which only last about 2 years.

After HP brought out the HP-28S, the calculator world seemed to go into stasis. Most new models were aimed at the finance market and, as schools and colleges had banned programmable models, I guess there was little incentive to make progress.

In recent years I have looked at the HP-48/49/50 and derivatives, with better displays and progressively larger memory and faster processors, but nothing that really felt like progress. Texas Instruments (TI) have come out with some powerful beasties with all sorts of functions but, again, nothing that really floated my boat. Except…

…Someone managed to get Manic Miner running on the TI-89 and 92+. I was seriously tempted at that point. But it was still very limited grey-scale, and looked more like a toy than a serious tool for science and engineering. My fx-3600p and HP-28S may be old, but they look like they were designed to do a job and to work for a living, not like My-First-Mobile-Phone for 4 year olds.

Yes, But What's The Point Of All This?

So, why am I saying all this? I mean, a chunk of life story is all very nice if you are my mother, and a whinge is good for letting off steam (come on, this is a blog) but what is my point? Well, my calculators aren’t getting any younger or more reliable, so I am now reluctantly in the process of looking around for a new one.

Below, you can see a couple of pages from the 1984 edition of the seminal consumer work The 1984 Argos Catalogue (aka the laminated book of dreams). See the selection available? There are seven programmables and many more scientifics. Now – not a single programmable one. These people sell full SLR cameras, iPods, iPhones, iPads, laptops and a million and one mobile phones, but just 8 scientific calculators.

Argos Catalogue 1984 - Calculators

So I looked a little further afield, and went to the manufacturers’ web sites to have a look at their key models.

Hewlett-Packard  

HP-35S, HP-39GS, HP-40GS, HP-48GII.

HP-50G Calculator

With the top of the range model, the HP-50G (pictured above). All these calculators are based on the ARM-9 powered HP-49 architecture and are manufactured on behalf of HP by Chinese company Kinpo. As you might expect, the quality took a nose-dive when HP stopped performing their own R&D and manufacturing, some time around 2003, with various complaints about a lack of key feedback, software bugs, and general build quality. Even Kinpo's web site seems to be bugged and missing pages.

Although they have improved the key feel in recent model revisions, the HP-50G still spurns the traditional (and excellent) shaped buttons which HP used in their earlier models. The up/down/left/right and function buttons also look rather dated in the age of touch screens. Note also how big it is in an adult male's hand. The UK price is a fairly reasonable £90 (new on Ebay, May 2011 price) or £90:34 excluding P&P on Amazon, but it looks too much like a toy to be taken seriously. Sure it has an SD card socket (not SDHC) and infra-red comms, but in these days of Bluetooth and WiFi those features only succeed in making it look even more outdated. A sad end to a noble brand.

Texas Instruments

TI-83+, TI-84+ (Z80 based)
TI-89 Titanium, TI-92 and Voyage 200 (68000 based)
TI-Nspire series (ARM based): Clickpad, Clickpad+CAS, Touchpad, Touchpad+CAS, CX, CX+CAS

The TI 73/83/84/89 Look very similar to the HP graphing calculators, so it is a fair bet that they are after the same market segment. The TI-89's design is notable in that they seem to have angled the keys closest to the edge, making them look a bit like a mobile phone design from a few years ago.

Texas Instruments
TI-89 Titanium

The TI-92 and Voyage(tm) 200 have an added QWERTY keypad (I can't really call it a keyboard). The effect is that it looks like it has been designed by a committee of 12 year olds who wanted EVERYTHING. NOW. We will hear more from these 12 year olds shortly... Quite honestly, if you can cope with something the size of the Voyage 200, then you should probably be using a netbook.

Texas Instruments TI Voyage 200
"Design - We've heard of it"

And now... (big fanfare)... The TI-Nspire Series. When I heard about the new TI Nspire series of calculators, I got really excited, and that isn't something that happens a lot with me (as you can imagine). ARM processor, full colour high resolution backlit LCD, real time 3D graphing, integrated rechargeable battery, USB, all in a slim case. Brilliant! I thought "This is what the market needs, something to move things into the 21st century, the calculator for the iPhone generation". Then I saw it. Oh mother...

The committee of 12 year olds are now 14 year olds, and they still want EVERYTHING. Except design, style, taste, and usability. The TI Nspire CX is 200x100x27mm. That is over an inch thick and 32 square inches of desk space. I calculate that it is double the volume of my already chunky HP-28S. And besides – look at the thing! Just in case you are under the mistaken impression that it is still pocket calculator sized, here is another view courtesy of TI:

Hang on - didn't TI say this thing was slim? My iPod touch is 8mm thick, this Nspire CX is 27mm. What are you talking about TI? It is very telling that TI is aiming these at the "educational" market. In other words, school children.Great, but what about us people who have left school and are now working for a living? Add to this the reluctance, actually no not reluctance - fear - TI seem to have of independent developers (call them hackers, makers, developers or for that matter simply enthusiastic owners) then I think we can remove all TI products from our virtual list of potential calculators.

Anyone considering playing around with TI calculators should read this: Texas Instruments Learns Nothing, Goes After Hobbyists Again

and this: TI vs. Calculator Hobbyists – AGAIN

TI seem to be in the increasingly large collection of companies which are under the impression that they can control the Internet. This tells me that lawyers are running the company, not engineers.

Casio 

FX-CG10 (FX-CG20) (new),
FX-9860GII (new), FX-9860GII SD (new),

Casio fx-9860GII SD

FX-9750GII (new), FX-9750G+,
FX-7400G+
CFX-9850GC+
FX-9860G, FX-9860G SD

That's a lot of calculators, and a lot of "number and letter soup". Too much, to be honest. Especially if you add the SD card options. I'm generally not keen on the curvy pseudo-phone look of the case, but at least the FX-9860GII adds -gasp- a backlight! Still, it is only a clunky monochrome screen with the usual set of applications we see elsewhere. I'm pushed to distinguish it from the HP-50G and TI calculators. It probably looks a bit more professional than the TI machines, but only marginally.

Fortunately, Casio appear to be changing direction. Presumably being forced by the appearance of TI's colour screen devices. The PRIZM FX-CG10. Urgh, not only a mis-spelled word, but in capitals too. For added confusion, it will be known as the FX-CG20 in the UK. I guess their marketing guys had to invent more work for themselves.

Casio PRIZM FX-CG10/CG20

Anyway, the FX-CG10/20 at least looks like it belongs in this century. They still seem to feel compelled to make the keys look like something from a mobile phone, and the colour screen is obviously not a touch screen, but it is a good start. No processor type is stated (my guess would be one of the ARM family) and the screen is lower resolution than TI's Nspire uses, but it looks a whole lot more professional. Almost HP-like in fact. Almost.

Will I be buying one though? Hell no. The UK price isn't too bad at £105, but it still doesn't do what I want it to do.

A quarter of a century on from the launch of my HP28S, I think we deserve more. There is no shortage of mathematical horsepower from ARM chips, nor is there a problem with memory prices or displays. Touch screens should be standard, removing the need for function and cursor keys (in this instance, a resistive screen would be better than a capacitive one, allowing the user to enter symbols directly with a stylus) but numbers and core functions should be retained as proper hardware keys with shaped buttons.

Software should be much more along the lines of the commercial heavyweights like Matlab or Mathematica. Wolfram Alpha is an obvious example of what the software should aim to be. I am not suggesting it be an iPod/Pad/Phone though, a calculator still needs to retain the immediate usability of conventional designs, whereby you can just flick a switch, and it is on and ready for use. Of course the real way of making it a killer product would be to open the OS and publish the hooks into the software, and to invite users to add to the available software. Pretty much the opposite to TI's attitude.

Conclusion (Yeah about time too!)

Hewlett-Packard
HP-35S

So, they are all useless? Well, useless is probably putting it a bit strongly, but I am disappointed that calculators haven't evolved more. The processor power available from ARM chips is hardly being used at all.

I am tempted to buy a Hewlett Packard HP-35S. It is made by Kinpo (urgh) and the OS is seriously buggy - to the point that the OS can crash, or erroneous results can be generated. But it looks a much more professional than anything else on the market. Come on Kinpo - sort it out! The HP-35S was brought out to commemorate the 35th anniversary of the original HP-35, but is the logical successor to the recent HP-33S. A calculator whose keys were angled in a V-shape, to look like - you guessed it - a mobile phone. It seems that someone at HP or Kinpo actually realised that professionals don't want their tools to look like a kids toy!

Is it too much to hope that someone might perhaps produce a successor to the superb HP-41 series? This calculator still has a huge amount of following, to the point that a number of emulators are available. Most notably, an emulator for the iPod/iPhone/iPad from Alsoft. Not only does it fully emulate an HP-41CX (including printer) but they have added GNUplot functionality too. Best of all, it is priced at just £15. HP are asking £30 for their HP-35S emulator.

Alsoft's i41CX+

Is this the future for calculators? I hope not. I would miss being able to turn on a physical calculator in a fraction of a second, and to receive direct feedback from the keys. I hope it will alert HP (and TI and Casio) to the untapped potential out there.

I would love to hear from anyone out there who has an opinion on this. I guess I am merely on the fringes of calculator geek-dom, I know there are some real collectors out there who go to extreme measures to get just the right calculator with an early serial number, but to me they are primarily an important tool and it frustrates me that nobody seems to make the right one for me.