Measure Gamepad Wires
Grab one of the gamepads and position it close to the PiTFT (In the photo, we're doing the DPAD first). We need to measure a piece of wire to see how long it needs to be for the first button (The left button on the DPAD). I recommend making it slightly longer so we have some slack and wiggle room.
In the photo, I have inserted a long wire into Pin #18 on the back of the PiTFT. By flipping the PiTFT over, I can see which pin is labeled.
Once we've determined a good length for our first connection, cut the piece of wire.
Strip & Tin Wires
Use wire strippers to remove 5mm of insulation from each tip. Then, apply a bit of solder to the tips to tin them. This will prevent the stranded wires from fraying and make it easier to solder to the pads.
Inserting Wires to PiTFT
To make wiring a bit easier, I suggest inserting the wire into the corresponding pin (#18 for the left button in this case) and threading it through until the tip from the other end is touching the hole. Then, bend the tip at a right angle so it can be held in place.
Solder Wire to Gamepad
Now we can apply some solder to the header pins on the Gamepad PCB. I suggest tinning the pads on the header of the PCB before soldering wires to them so it's easier.
Although the photo shows the wire orientated from the top, I recommend positioning the wire from the bottom. This will make securing the PCB to the 3D print case easier.
Repeat this process for the rest of the buttons, up, down and right. Each button requires a different length of wire. I recommend referencing the wiring diagram closely and double checking each wire is in the correct positon. Also, try doing one wire at a time to prevent any confusion.
Test Gamepad Connections
It's a good idea to test your connections! Using a multimeter in continuity mode, you can probe the header pins on the PiTFT and gamepad to see if the connections have continuity - You'll hear a "BEEP" sound if the connection is solid.
With patience and persistance, you'll end up with two gamepads wired up to the PiTFT.
This part of the build is the most time consuming, so try not to rush it. Once complete, feel free take a break :-)
In the next page, we'll solder the Pi Zero to the PiTFT and sort out the other components.