qn8007_fm_tx
FM transmitter based on QN8007 with MP3 player and PA
- USB powered
- Uses DFPlayer MP3 player module (available from aliexpress)
- 1W PA using RQA0009
- Integrated output lowpass filter
Building the software
- Download and build libopencm3 (https://github.com/libopencm3/libopencm3)
- Build:
cd qn8007_fm_tx/sw
export OPENCM3_DIR=/PATH/TO/LIBOPENCM3
make- Download and build st-link software (https://github.com/texane/stlink)
- Flash device (using ST-Link, available from aliexpress)
cd qn8007_fm_tx/sw
rm st-flash
ln -s /PATH/TO/STLINK/build/Release/st-flash ./
./st-flash --reset --format ihex write binary.hex
# or 'make flash'MCU UI
- There is currently no GUI, but there is a UI consisting of the 4 buttons and one LED
- The 4 buttons correspond to return, <, >, and enter
- To change the frequency: press return and enter at the same time, and the LED will stay lit. Then < > adjusts frequency by 0.1MHz, and double clicking < or > adjusts by 1MHz. Press return to exit frequency adjust.
- In normal operation the LED blinks with a rate proportional to temperature. A continuously lit LED corresponds to the thermal shutdown temperature.
- In normal operation the code plays songs at random from the SD card, and double clicking the > button skips the current song.
PCB stackup
- 4 layers
- FR4
- 1.5mm total thickness
- 0.2mm top/bottom prepreg thickness
Top view
Bottom view
To open schematics, it is necessary to add all gEDA symbols here to your symbol library: https://github.com/gabriel-tenma-white/sym
To edit PCB layouts, make sure "packages" is a symlink to a cloned repository of: https://github.com/gabriel-tenma-white/packages2