If you grew up using an Apple II computer of some flavor, likely you have fond memories of playing games like Karateka, Oregon Trail, or other fun and/or educational titles. perhaps you never considered it at the time, but how neat would if have been if one those computers could be transported to whatever location you desired to be used without external power?
Chris Larkin, a California-based software engineer, decided to take on this challenge (see his GitHub writeup) using already designed 3D print file of the Apple II computer (base, monitor), and added his own custom bracket for a CHIP computer. This computer emulates an Apple II using LinApple-Pi software. The resulting build is an extremely small version of an Apple II computer that looks strikingly like a tiny version of the original (or at least one iteration of this system).
Power for this setup is provided by a high capacity 12 volt “drone” battery, which Larkin estimates will give him about 10 hours of use between charges. Deciding on this setup was a bit of a challenge, as the monitor required 12 volts, and the CHIP can only handle about 5. Originally he tried to use a 3.6 volt boost converter to power both, but this only gave about an hour of battery life and ran hot. In the end, he ended up instead stepping down this 12 volt power with a buck converter to power the CHIP.
Once you dig a little further into the build, there are a few things you might not expect on an Apple II, including a composite video socket on the back. One might suppose this is an output to let the little Apple II act as a sort of console, but it’s actually one of the inputs from the tiny Adafruit display he used. As if you plug in another video source, it will use that as the system’s input instead of the CHIP/Apple II.
Another difference is that the keyboard is non-functional. According to Larkin:
[Having a functional keyboard] was the original plan, however the effort required to do that would have added about a month to the project, and I’m fairly sure it would be a terrible experience to use. I would also have to redesign the case and keyboard a bit as the keyboard as it is now is not exactly the Apple II layout. I ultimately decided that a tiny Bluetooth keyboard would be just as portable and much easier to use.
This certainly makes sense, as it took Larkin three months to build this Apple II “clone” from start to finish. He notes that much of this was spent waiting on parts. Although this build is certainly in a presentable form at this point, it seems that maker projects are never really done (at least mine always seem to need just one more tweak to be entirely complete). According to him:
The current 3D print is a bit rough, I do plan to make a few more with a much higher resolution print and more clean up on the surfaces before painting. I also plan to expose the CHIP’s USB port to the back of the computer to allow for things like USB Joysticks in the next version.
The screen is built to swivel up and down a bit in its frame just like Apple II did, and it does. However the glue I used to secure the screen into the frame is not quite up to the task, so we don’t tilt it much anymore to prevent any damage to it. Future versions would have to find a different way to attach the screen to the frame.
He also notes that if he were to build it again, he would include a USB breakout on the back so that accessories such as a joystick could be plugged in. Still, it’s a great build, as seen in the following videos. The first shows a basic overview of how it works, while the other shows it playing Karateka with a USB keyboard.