IPAC

your external keyboard, made of anything conductive

aka the makey makey on steroids :)

The I-PAC2 has 32 inputs which are all programmable and are marked as 2 joysticks, 8 buttons each, plus coin1, coin2, start1, start2 and MAME control keys. Any inputs can be assigned as a shift key to access an alternate code set. I-PAC is the ONLY keyboard encoder where each input inputs has it's own dedicated microprocessor pin. No interaction or delays, vital for multi-button games such as fighting games. I-PAC is much more than a keyboard encoder! Pins can be configured as mouse buttons or game controller buttons, plus power and volume control. I-PAC is the ONLY keyboard encoder which emulates a USB keyboard and yet breaks through the USB simultaneously-pressed-switch limit of 6 switches (plus ctrl,alt,shift) which afflicts all USB keyboard devices. I-PAC is the ONLY device to have a shift function which allows ANY input to be assigned to a shifted secondary keycode and the shift button can have it's own function too so no need for a dedicated extra control panel button. I-PAC is the ONLY device to have a self-test LED which not only gives an instant visible check of your installation but also can indicate which connection (if any) is causing a problem. I-PAC retains it's programming after power off. Not all keyboard encoders do this!

read up on specs here or here:
https://www.ultimarc.com/control-interfaces/i-pacs/i-pac4-board/
download custon software: https://www.ultimarc.com/download.html

mapping: