The Raspberry Pi holds incredible promise for those looking to build a small mobile terminal that they can take with them on the go, something you can throw into your bag and pull out whenever there’s some hacking to be done. But getting the diminutive Linux board to that point can take quite a bit of work. You need to find a suitably small keyboard, design a custom case, and wire it all up without letting any of that pesky Magic Smoke escape.
But a recent project from [remag293] might make things a bit easier for those looking to get their feet wet in the world of custom mobile computers. The boxy handheld device has everything you need, and nothing you don’t. A basic case, a short parts list, and an absolute minimum of wiring. What’s not to love? Even if you don’t make an exact clone of this device, it’s an excellent reference to quickly bootstrap your own bespoke terminal. threaded structure plastic parts
So what’s inside the 3D printed case? Not a whole lot, really. Obviously there’s a Raspberry Pi, a 3.5 inch TFT touch screen display, and a miniature keyboard. The keyboard is of the Bluetooth variety, and other than being freed from its enclosure and wired into the header on the display module for power, it’s otherwise stock.
As for the parts you can’t see from the outside, there’s a 3.7 V 4400 mAh battery pack and an Adafruit PowerBoost 1000 module to handle charging and power distribution. Beyond the big lighted button on the side (which you could certainly replace with something more low-key should you chose), that’s about it. When it’s all together, you’ve got a battery powered computer that’s ready for the road with a minimum amount of fuss.
If you’re looking for something that’s a bit larger, and more than a little unconventional, you could start by printing out a full cyberdeck. After all, if you’re going to build your own non-traditional portable computer, you might as well go all out.
Inspired by talk of custom carbon pill keyboards a few months back on HaD, and interested in implementing a vaguely secure/trusted pi based terminal similar to this, I investigated silicone keyboard membranes with carbon pills that could go on a custom pcb which would also accomodate the pi and a display. In the end, sourcing even off the shelf silicone membranes was cost prohibitive, with quotes on alibaba etc of ~USD$18.40 each for 1000 of a suitable, existing (!) silicone keyboard design, when fully functional usb or bluetooth keyboards, often tactile membrane based +/- bluetooth, were much cheaper, but this was at odds with the notion of eliminating bluetooth and usb controllers. The contemplations died at this point.
There would probably be a market for such a device, if a suitable keypad could be sourced at a good price.
++1 Or some way of easy reuse of an cheap mini wireless (bluetooth or rf) keyboard and connect it to an cheap arduino with HID like the ATmega32u4 based ones.
Custom keyboards like that I think would have to be a home machine shop rubber mould job. For me just use proper mechanical switches (preferable fully size keyswitches so you can actually type on them!). You can get momentary surface mount push button in pretty much any size rather cheap, add ’em to a pcb full of traces and it is a cheap custom keypad (though nothing will ever match mass produced for price – so if you really really must have it cheap but chip less buy a keyboard and take its matrix straight to the Pi.)
Though if you really want ‘secure’ a Pi while ok doesn’t make sense. You want a FPGA based system, as that will be almost impossible to bugger with all the way through. As even nefarious silicon fab house can’t know exactly what logic gates and pins will be set up for.
If you are making a couple for yourself, consider buying the wireless keyboard and rip out the wireless PCB. There is a flex PCB (conductive ink) connecting the keyboard matrix to the wireless PCB. From there it is a matter of mapping out the matrix with a multimeter.
Reminds me if the old TRS-80 Model 100. I wish they still made LED screens like they had.
https://en.wikipedia.org/wiki/TRS-80_Model_100
LCD screens, and I’ll go with the keyboard that thing uses as well.
That was an L*C*D screen. Not LED.
@McNugget: Yes. Yes it was.
I actually used one of these back in the day to diagnose DEC terminal server issues. Well, OK, really just to see if I could get a login prompt before bring up the Tek 4107 terminals (Noodly FSM those were heavy!). Using the Carroll Touch Technology RS-232 breakout box was fun, what with all the blinkenlights.
What is the meaning of “terminal” here?
That is kind of my thought. I seems funny to use what is a pretty potent computer (compared to the room filling monsters I used to timeshare on) and use it as a terminal! I think of a terminal as a screen, keyboard, and a serial port out the back end. I guess I am OK if a full unix system is embedded inside.
Well even DEC thought VT-100s were a bit wasted waiting for an oversubscribed mini-computer or mainframe to respond over a 2400 baud or slower line, so came up with… https://en.wikipedia.org/wiki/VT180
That’s funny. I don’t remember that – you buy a terminal, and as an option they’ll throw in a computer!
I’m guessing “endpoint”, phones/digital radios are called terminals in the industry.
You perhaps are confusing “terminal” with teletype.
what exactly do you mean by “the industry”, what “Severe Tire Damage” is saying makes completely sense for “the industry” of 3 or 4 decades ago. Personally, what I find very funny, is that there are a lot of terminal emulators (computer programs that is) that aren’t capable of handling the standard control characters, a simple ‘clear screen’ and ‘move cursor’ for example. The word terminal is loosing it’s grip.
This project is a nice example of overkill, but who’s to blame, it’s easier to take a 10$ computer board that can do more then the device it will be connected to, than it is to make a much more limited device that only is capable of performing the task it should do. And why bother, if it does the job and the maker is happy, it’s fine. And looking at the photo, it looks nice too.
then every microcontroller everywhere is overkill, about. 90% of the peripherals are left unused in just about every application
every automobile on the road is overkill unless it is filled to cargo capacity whenever it is driven
your definition of overkill is the epitome of overkill
I wasn’t replying to Severe Tire Damage, which is a sibling post, but the shared parent post about “what do they mean by terminal”
The Phone manufacturers, and Digital Radio Manufacturers (the industries mentioned) call their devices terminals. Because they are the endpoints.
Usages with similar meanings are Air terminal where flights start and end, battery terminal where electrons flow from and to.
Computer terminals are/were endpoints of a computing device one of which was a teletype.
I hope that I’ve helped with any misunderstanding there.
I did this before but with a gutted HP Network Analyzer and doesn’t use a battery but Mains Power.
Pics or it didn’t happen! (Or link. Please? :) )
It’s on my Blog.
https://wordpress.com/read/feeds/82902097/posts/2382870282 https://wordpress.com/read/feeds/82902097/posts/2364862791 https://wordpress.com/read/feeds/82902097/posts/ 2353202620 https://wordpress.com/read/feeds/82902097/posts/2351299992 https://wordpress.com/read/feeds/82902097/posts/2345566405 https://wordpress.com/read/feeds/82902097/posts /2336050863
It’s on my second Blog theitgarage dot wordpress dot com
Please be kind and respectful to help make the comments section excellent. (Comment Policy)
This site uses Akismet to reduce spam. Learn how your comment data is processed.
injection molding nylon 66 By using our website and services, you expressly agree to the placement of our performance, functionality and advertising cookies. Learn more