Building the Circuit

• Cut a short length of wire for each contact on the Atari PCB, and one for ground. I've color-coded them similarly to the original wiring. Since I didn't have brown wire I substituted it for yellow
• Strip a bit of insulation off of the ends of each wire

USB Breakout

In order to charge the battery we will need to extend the USB port to the outside of the joystick. Prepare the USB breakout board by soldering a red wire to it's +5V and a black wire to its ground

Switch Prep

This slide switch will be used to turn the microcontroller on and off. We can do this by grounding the enable (En) pin on the Feather.

• Remove one outside leg from the switch with diagonal cutters, then tin the two remaining leads
• Solder a black wire to each of the switch's leads
• Cover them with heat shrink tubing for insulation
• Use a larger diameter piece of heat shrink to cover both legs

Switch to Enable Pin

Solder one of the wires from the switch to the enable pin. (It doesn't matter which one.)

5V to USB

Solder the red wire from the USB breakout board to the USB pin on the microcontroller.

This will be used to charge the battery.

Shared Grounds

• We will twist together and solder the three ground wires before connecting them to the single ground pin on the Feather. One is from the switch, the second is from the USB breakout, and the third is the wire we'll be connecting to the joystick PCB

This wire can get too thick to fit in the Feather's pin through hole, so be sure to use a light hand with the solder when initially joining the wire ends.

• Insert the combined ground wires into the microcontroller's ground pin, then solder the connection

Feather to PCB Traces

• Now place the microcontroller inside of the joystick body as shown and placed the original PCB onto its mounting holes
• Trim the pin connection wires to a proper length to fit, with just a bit of extra wiggle room. If the wires are too long they may make it difficult to fit everything inside
• Next, solder the connecting wires to the original Atari PCB as shown

Battery Power

• Use a little bit of double stick foam tape to secure the battery inside of the joystick body as shown
• Plug the battery's JST connector into the Feather microcontroller.  If the controller turns on, go ahead and flip the switch to turn it off

Switch and USB Port

• To secure the slide switch and USB breakout to the joystick's cable port, use some double stick foam tape
• To maintain the look of the controller, you can blacken the edges of the tape with permanent marker