/qn8007_fm_tx

FM transmitter with MP3 player and PA

Primary LanguageC

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

cd qn8007_fm_tx/sw
export OPENCM3_DIR=/PATH/TO/LIBOPENCM3
make
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

UI buttons

  • 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

picture

Bottom view

picture


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