kicad file with ports to connect the pcb directli to raspberry pi 3B+ about cff3000-pcb HOT 1 OPEN

You can already remove the battery when you connect the remote control's Vcc to the PCB. I use the SoC's 3V3 as power supply for the remote control. Actually you should only connect either the remote control's Vcc line OR insert the battery, but not both at the same time.

Of course you can modify the form factor of the PCB, so that it becomes a RPi hat and/or add some space for the remote control pcb. I provided the PCB as documentation for the electrical wiring.

I suppose the clean solution would be to analyze the data sent between the PIC16LF1829 micocontroller (sidenote: the 5 pin connector on the PCB is connected its ICSP interface) and the MRF89XA RF chip on the remote control and design a new PCB with onboard RF chip directly wired to the single board computer. Digikey offers a module, that can even be soldered by beginners.

from cff3000-pcb.