There is some hardware that can be made with a 3D printer or laser cutter. An assembly manual is currently being prepared.
6 to 12 inch divided e-drum pad
6 to 12 inch divided e-drum pad without shell
6 to 12 inch one piece e-drum pad
Mount parts for Roland and Yamaha's Tom Holder
Parts to make 8 inch pad a bass pad
TCRT5000 or FSR
Simple kick trigger unit
Arduino based trigger to MIDI converter
3 zone cymbal pad