|Re: Let's build a calculator...|
Message #25 Posted by DaveJ on 16 Apr 2009, 7:56 p.m.,
in response to message #1 by robert rozee
Well, what a coincidence... just last night I started back-of-the-envelope work for a Mk2 uWatch. Time will tell if anything comes of it...
Forget software, don't even think about it, the hardware is *everything*.
Without a decent hardware platform to work from a calculator does not exist. This has been proven time and time again with DIY calc projects. Once you have a hardware platform, the software will come, the software is flexible, and there is no shortage of code and coders out there. It never ever works the other way around for something like a calculator, unless your aim is purely a software project and you don't care about how crap the hardware is.
Forget group projects, they are doomed to failure. A project like this needs one person and one person alone to come up with some hardware and make all the decisions.
The hardware is not trivial, in fact it is very difficult.
Sure, in a day I can lay out a circuit and a PCB with a processor, some switches and an LCD, and it will work like a calculator. Unfortunately it will look and feel so "prototype" that no-one will want to use it.
Ask Eric how much time and effort he has put into his DIY-RPN calc, that has only in recent revisions just started to resemble something that people would be happy to use physically.
Unless you have the resources and money of a large company, a fully custom calculator hardware design that looks and works like a decent product is very difficult to achieve. And if you can't achieve a reasonable working quality, I say don't bother.
Hardware is not cheap either. Yes, processors are fairly cheap, blank PCBs are cheap, but things like quality switches and LCD's are not. At least not in small volume. My uWatch is expensive because the parts are expensive, and all the small parts add up. The switches are expensive and single source, connectors are expensive, battery holders are expensive, some of the screws are a dollar each etc.
You have to either cheat and/or be very very clever in off-the-shelf part design if you want to produce a calculator that people will want to buy and use.
On the uWatch I cheated a lot. I used a PCB for the front panel and labeling, I got away without keytops, and by the novelty of the design I got away without a custom case or any other custom parts.
It is not a hugely usable design, but it's the only one out there and it's novel. So it's been reasonably successful in a niche way.
Quite frankly I've come to the conclusion that it would be a waste of time and effort for anyone to try and do a full-size custom DIY calculator.
There are just too many hardware options available off-the-shelf. The iPhone, PDA's, the Casio 9860, the HP 20B, HP48/50 and even some TI's can be preprogrammed? etc
And newer calculator designs are becoming more more open and re-programmable. HP are moving in this direction.
There has been talk about hacking an existing product (e.g. LCD and PCB replacement), and that may have some merit to a niche market if someone can find a cheap and easy way to do it.
If your goal is to have a new HP42 then you can have that right now on an iPhone or other device. Why anyone would bother with a custom hardware project to recreate the real thing is beyond me. All that effort, time and money, just so you can have something with real buttons seems a tad silly, even if you did manage to pull it all off at a reasonable price and quality.
If you really want a high end DIY calc, don't waste time and effort doing it from scratch. Simply take an existing re-programmable calc, use it as the hardware platform, and look at changing the front panel and key legends. Low cost, low risk, short development, and a high quality result. You won't get that result with DIY from scratch for any cost you'd be able to afford.
What do I think is a worthwhile project?
Given the above that the full size calculator market is difficult and options already exist. I'm going to concentrate on smaller calcs, with either another watch, or maybe even a REALLY TINY shirt pocket or belt clip calc.
My current sketches and thinking show a tiny (38mm x 27mm) 128x64 LCD, small tact switches again (but possibly bigger than the uWatch) that surround the screen, and the PCB front panel worked good last time. A thin rechargable battery, perhaps some rocker encoder switches, and a more powerful processor.
The case and front panel integration is the hardest part, but I have some ideas that may simplify this.
I'm getting the initial feeling it should be possible to come up with a smaller, thiner uWatch with integrated watch band, more rugged, and a dot matrix display that takes much less power.
Fewer keys probably, but anyone who thinks that is a negative is missing the point of a project like this.
The uWatch is fiddly to assemble and not very rugged. That is why I have not sold it as anything but a kit. Also, the uWatch is very niche because it's pretty much just a calculator and not much else, and most people don't want to buy a kit.
So any next device I picture being less calculator-like, and more general purpose computing-like. Easier to assemble, more rugged, and sellable as a built-up product. Not designed for the calculator enthusiast market, but the infinitely bigger geek market. (Flame mail welcome)
Yet, I also plan to keep the uWatch's off-the-shelf parts concept to keep development costs down. Perhaps a custom case will be needed, but I have an idea to possibly make that simple enough I can do with my feeble mechanical CAD skills.
Oh, and last but not least. It doesn't matter what you come up with, you will never ever please anything but a minority. And even then they'll still want something different.
Will I actually go through with it? Don't know, I work on whims :->
Edited: 16 Apr 2009, 9:45 p.m.