Radio direction finding multi-function radio

Researching
radio direction finding enthusiasts, I often find myself waiting for hours in the registration area during competitions, with no cell phones or other transmitting devices allowed. It's incredibly boring! Since they don't explicitly forbid radios, I decided to build one. Later, I added many absurd functions, resulting in this, which became a graduation gift for a classmate.
I'd like to thank Wende High School for their six years of nurturing, and the teachers and classmates for their companionship. If any alumni or faculty members read this, they will surely cherish those unforgettable times playing on campus. I also hope the school's direction finding team will continue to improve and excel in various competitions. Go team!

May your future be bright and even more exciting! This device
adds
a flashlight, temperature comparison, light comparison, and FM transmission functions to a basic radio, using AAA batteries for easy replacement. The comparison function simply involves checking the brightness of the LEDs; it's all hardware, allowing for easy secondary development. I must
clarify that
I'm not sure if this device will actually be allowed in the competition; I need to consult the organizers. I need to ask the direction finding judges in Guangzhou. I'm posting this article first, and we'll discuss the rest later. It should work without the GFT809.
The schematic design instructions state that
the parameters of the thermistor and photoresistor can be adjusted, or different parameters can be directly replaced.
FM transmission is controlled by a DIP switch; I haven't tested it specifically, you'll need to check the frequency yourself, but I know 1 0 0 1 0 is roughly around 89MHz.
There's a surface-mount IC for playing music; you need to bend the leads and then mount it upright. Those who know, know; those who don't, just enjoy the music.
Soldering and debugging instructions:
First, completely block the photoresistor so it's completely dark. Then, use a non-conductive screwdriver to adjust the variable resistor until no light illuminates.
When soldering, be careful not to touch the metal cover of the switch; melting the plastic switch inside will render it immobile. Soldering 0402 requires a higher level of skill; you can replace it with 0603 on the PCB and then build the board.
Finally, connect it with an M.2 connector.