I’ve finally got round to posting about the raspberry pi arcade. I’ve build an ATMega based board to convert all the controls to SPI for the raspberry pi, modded the ada-friut retro arcade library to use the SPI based control inputs and etched a PCB for the control board.
I home etched the PCB using the toner transfer method which I find to be a bit of a pain to get a decent result. The best way I’ve found is to print on magazine paper, then iron on for 5 minutes and finally run through a laminator four or five times. Here is the result:-
The board does a few thing. It has 2 9-Pin D connectors for the player 1 and player 2 controls. The layout is the same as an old atari joystick (in theory you could plug in old Atari comparable joysticks). The unused pins on the D connector are used for the extra buttons and the player 1/2 buttons. The joystick axis connect to analogue inputs on the ATMega to save a few pins. There is also an input for a coin mech to add credits, at the coin mech requires 12v the board requires a 12v and 5v supply. The 5v supply goes thorough a regulator so that the board runs at 3.3V (8Mhz) this removes the need for logic level conversion between the board and PI.
The above pictured board had a few issues (it also had a zener for the coin op mech which has been removed). I put a few jumper wires on the bottom to correct the issues, most of which were due to eagle not connecting nodes so I should probably pay more attention to the ERC check. An updated design is checked int github at https://github.com/markpudd/PiArcadeBoard. Here is the populated board connected up:-
The other thing I’ve done is sprayed the cabinet black, added the coin mech and stated to put on the plexi glass:-
Only a couple of more things to finish (bevel and marquee) so will post later in the week with the finished result!