I'd be happy to help anyone that wants to build one. In the link up above I tried to list the parts and how to build one. The board I used has its own programmer built in, so there's nothing extra there. I used a template from someone else (based on someone else's template, based on ST's sample code), and the README.md in the code has all the instructions on how to setup an environment to build the code and program it. If someone is really interested in building one and programming it is the stumbling block, we can probably figure something out like a virtual machine that has everything ready to go or something.
The short version is that board I used is ~$8 from digikey, I used two premade level converters from adafruit to do the 3.3V to 5V conversion, and then the connectors which I hacked up from existing cords. I'm just using GPIO signals on the board to talk to the Plus on one side, and the PS2 keyboard on the other. It then has a table to convert the scan codes between the two. I'm currently mapping all the keys on the original (non-keypad) keyboard. I'm also using a (ttl) serial port on the board for diagnostics. The windows keys on the ps2 keyboard are the cmd key. I'm not actually implementing all (only 4) of the mac keyboard commands at the moment, the Model Number and Inquiry commands are the two that really need implementing. The other big one is the Instant command to return the keys down at that very moment, but I haven't seen that command actually issued in my testing.
As for the amber screen, it came in one of the Plus' in that big lot. I used it here to see if it got any better results in the video than the stock screen.
The short version is that board I used is ~$8 from digikey, I used two premade level converters from adafruit to do the 3.3V to 5V conversion, and then the connectors which I hacked up from existing cords. I'm just using GPIO signals on the board to talk to the Plus on one side, and the PS2 keyboard on the other. It then has a table to convert the scan codes between the two. I'm currently mapping all the keys on the original (non-keypad) keyboard. I'm also using a (ttl) serial port on the board for diagnostics. The windows keys on the ps2 keyboard are the cmd key. I'm not actually implementing all (only 4) of the mac keyboard commands at the moment, the Model Number and Inquiry commands are the two that really need implementing. The other big one is the Instant command to return the keys down at that very moment, but I haven't seen that command actually issued in my testing.
As for the amber screen, it came in one of the Plus' in that big lot. I used it here to see if it got any better results in the video than the stock screen.