GTA Radio Transmitter

This device plugs right into the cars cigarette lighter port and transmits an FM Radio signal, so you can listen to your favorite GTA radio stations, using your cars radio. The software part is not properly documented and I had to reconstruct some steps from memory, so recreate this at your own risk. This is not a step by step tutorial, this is the best I can do without building another one. I am also in no way a professional, so possible legal and fire risks are your responsibility if you choose to proceed.

1. 3D Printed Enclosure: https://www.thingiverse.com/thing:7153182/files
2. GC9A01 1.28 Inch Round TFT Display for Arduino
3. 3.5mm Universal Car FM Transmitter LCD
4. Reload Car Charger RL-CH-C2P0524-W (Hard to get you can probably use most car chargers)
5. Rotary Encoder KY-040
6. Raspberry Pi Zero W (a regular one will work too but working on it without an ssh connection is more tedious)
7. Resistor

For the enclosure, download GTARADIO_BOTTOM.stl and GTARADIO_TOP_HOLE.stl from Thingiverse: https://www.thingiverse.com/thing:7153182/files

The file GTARADIO_TOP.stl has a design oversight, where the pi doesn't fit when an sd card is attached. This way you always have access to it. Feel free to edit the stl for a more elegant solution.

Please consider that in summer, the inside of a car can reach temperatures higher, than the melting point of some Filaments.

Before anything, turn on the FM Transistor and set a frequency. As it is very hard to reach when in the case, choose one that's unused in your area and working fine. Now, remove the FM Transmitter from its casing. Then you have to remove the battery. Be careful not to short the signal. Next, desolder the aux connector. Prepare 5 wires and the resistor and solder them like shown in the image (but cleaner). Make sure to leave it's power switch in the on position.

This step will vary slightly depending on the car plug you use. Open up the top part and pull the circuit board out. To make the top part fit inside the casing, I had to trim it shorter, meaning I had to remove the usb ports, and solder 2 wires directly instead.

Insert the plug into the bottom part of the enclosure. Make sure it doesn't pertrude past the edge of the top hole. Also make sure to route the wires through the bottom slit, as the top hole will be blocked later. Get the plug into an angle you like and glue it to the enclosure. I used a screwdriver to hold the position and this angle worked out well for me, as it makes the screen tilt a bit forward.

As the build is pretty compact, we don't have room for the pins, that are usually preattached to the display and rotary encoder. Remove them and instead solder on wires.

Follow the wiring on the image. I am also not completely sure if it is correct, because I could only recheck it from videos. The cables from the car plug are connected to the test pins on the back of the pi zero.

Video of the Connections, to check them again: https://drive.google.com/file/d/1X_ihVOaUpNwWC8s1NDlztSGrtPIv0euN/view?usp=sharing

As I haven't documented, while building, this step will have to be done with your own research. I tried to find links to the sites I used, but they may not all be the same.

https://learn.adafruit.com/adding-basic-audio-ouput-to-raspberry-pi-zero/pi-zero-pwm-audio

https://www.instructables.com/Connected-Round-Screen-240x240-GC9A01-Controller-t/

I also attached the python scripts, that I am pretty sure I used. Note that it is some of the worst "programming" seen by man and possible future employers please don't throw out my resume because of this

Now all that's left to do after testing that it works, is final assembly. Place the fm transmitter between the screwholes and fixate it with glue or in my case molten plastic. Put isolating tape on top and on top of that add the pi zero, that you can screw in. On the other part of the case position the screen so that it's straight and glue it on also. Put the rotary encoder through the hole and be careful, to glue it in a way that doesn't destroy the down click. Alternatively you can also fixate it with the nut it comes with. With everything glued in place push the cables together and try to close the case.

You might have done it, congratulations. If you improve the code or the 3D Model or anything, feel free to upload it. If you write a better instruction for the software, tell me so we can make this project more accessible.