Interesting prototyping approach

[mfleming]

I thought this Crowd Supply project, the ELLO 2M, might spark a few ideas for those who have been constructing their own calculator prototypes. The approach taken by this builder is to construct a simple computer using a stack of six PCB's. The processor, memory, keyboard, keys and display are all contained within or constructed from one of the PCB layers. Here's a link to the project

https://www.crowdsupply.com/knivd/ello-2m

Looking at the second posted video, the keyboard certainly doesn't look "HP quality" but it would be adequate, and obviously easily changed. Certainly a fairly clever twist on the task of producing a prototype.

~ Mark

   

[BobVA]

That is pretty cool looking. Kind of reminds me of the Tandy Model 100/102, but pity it doesn't have the nice, full-travel mechanical keyboard of that classic.

Their keyboard is a clever design. But, for a calculator with a high density of keys, I'm not sure how much of an improvement it would be over surface mount tactile switches (e.g. NP-25/41)? Do you think their model would scale down in size (i.e. smaller buttons) without an undue increase in actuation pressure? Maybe with a thinner top layer? It would be interesting for a simpler/larger calculator design, though.

OT: I've used the MicroMite microcontroller (PIC32 family) / MMBasic in a couple of little projects. It's got a very complete set of I/O interfaces with direct support for I2C, SPI, serial, 1-Wire, PWM, servos, LCD displays, etc. and is reasonably fast. I hope a lot of that carries over into this project.

I've thought about putting a MicroMite into either a Tandy 102 or WP-2 as a "coprocessor" for improved BASIC and prototyping support. I think it would be reasonably straightforward as the MM works fine with a serial terminal, and let's you set a lot of parameters.


Bob

[Garth Wilson]

I do like some of the ideas there, and I wish him success.

Related to what he says about low-cost alternatives (which I've seen plenty of), I can say that nearly 40 years ago, I was super interested in photography. I learned to develop my own film and I had access to a darkroom to print my pictures. At a very low cost, I got a roll of 100 feet of bulk 35mm film which I would load into the cassettes myself, and thought, "I can finally afford to quit being stingy in what pictures I take!." But what happened was that the low cost made me a lot less careful, and the number of good pictures I got actually went down, not up. (I think you can see where I'm going with this.)

Today's young people expect everything to be ultra cheap; and in computers, they want everything done for you. Heaven forbid that you should have to do anything in assembly language, or go without simulators and debuggers, a GUI, and so on. I saw a video recently—and I wish I could find it again—that talked about making computers understandable by using understandable computers, like the Commodore 64. Ones that have lots of layers of software insulating the user from the bare metal don't qualify, nor do ones with layers of cache, memory protection, DMA, etc.. I know something like this basically does need an SD card interface today, but SD is not easy to understand. USB certainly is not the least bit hobbyist-friendly either, and must be treated as a black box by relative beginners. The same goes for WiFi and Bluetooth.

Kudos to him for including a prototyping area.

I can't say I'm familiar with the PIC32, but I don't get the idea that it's suitable for the beginner to program in assembly. Randall Hyde, author of "Write Great Code (No Starch)" has an essay online, "Why Learning Assembly Language Is Still a Good Idea" which has a lot of good comments about how knowledge of assembly helps you write more-efficient high-level-language code. He is an instructor at the University of California who laments the two decades of unwise "assembly-is-dead" teaching that has been in the schools. Part of the reason to learn an assembly language is to learn machine organization, the subject of volume 1 of the book "Write Great Code" by the same writer.

Forth is a language that has no need of simulators or debuggers. That would be a good one to make available for the Ello.

Working for small, low-budget outfits (which I enjoy), I have found that the lack of expensive debugging tools actually teaches you to write better code. (Many of the development tools are free today, but it wasn't always that way.) You can't have the attitude that "I'll whip out this code in record time and debug it later." Out of necessity, I've become more structured and neat in my programming, documenting everything thoroughly, making the code as readable as I know how, and proofreading. The result has been that no end user has found any bugs in any of the embedded software I've written for our company over the decades.

I do wish Ello had a standard battery that we could know we can get replacements for, many years down the road.

Quote:Kind of reminds me of the Tandy Model 100/102, but pity it doesn't have the nice, full-travel mechanical keyboard of that classic.

I agree. I can't type on my laptop nearly as accurately as I can on my desktop which uses a full-travel keyboard. So much of the modern stuff has a push to be excessively thin.

[Dave Shaffer]

(05-31-2016 07:06 PM)Garth Wilson Wrote:  I do like some of the ideas there, and I wish him success.

Related to what he says about low-cost alternatives (which I've seen plenty of), I can say that nearly 40 years ago, I was super interested in photography. I learned to develop my own film and I had access to a darkroom to print my pictures. At a very low cost, I got a roll of 100 feet of bulk 35mm film which I would load into the cassettes myself, and thought, "I can finally afford to quit being stingy in what pictures I take!." But what happened was that the low cost made me a lot less careful, and the number of good pictures I got actually went down, not up. (I think you can see where I'm going with this.)

Wow - do I agree with you on this, with regard to digital photography. I took slides for 40 years. That cost almost a dollar a shutter push by the time you were done (film + developing). In those 40 years, I took some 7000 frames.

Now with my digital SLRs, I have taken probably 100,000 frames in less than 10 years, and on average they are nowhere near as good as the slides.