Took the pad out of a knock-off ps3 controller and crammed it in the joycon. Had to take half a centimetre of material off the back of the dpad to make it work lol.
Got a dirty ps3 controller with a dead battery and somewhat worn sticks. Cleaned it up in hot soapy water and put the button membranes in some boiling water to restore the springiness, stuck a new 1000mah battery in and replaced the sticks with some ps4/xbox one metal sticks which required a 2mm...
It's made from an old hdd brick with 5+12v, a step down converter for 3.3v, a cut up usb 3.0 header, solid core wire from an ethernet cable and some old ass switch from a box of shit.