====== Chinese FM-transmitter ======

Following is a quick disassembly of a 3€ [[https://aliexpress.com/item/1005008839803108.html|🛒 no-name Chinese FM-transmitter]] with Bluetooth 5.4, Aux and SD-Card. 
Next to the 7 segment display, there is a microphone for hands-free input. \\

[[projects:rlink2#gadgets_you_can_get_for_your_car|Also see "Gadgets you can get for your car"]] \\
===== Photos =====

{{gallery>:disassembly:fm-mp3}}
===== Notice =====

The USB tin shoe holds the casing together well. \\
USB is not only for 5V, data lines go to MCU/SoC. \\
The MCU is //[[https://www.reddit.com/r/AskElectronics/comments/tcqi6f/comment/i0fyeed/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button|AB-series from Bluetrum]]//. 
There is a [[https://gitee.com/bluetrum|gitee repo of bluetrum]]. On first sight, it does not seem to be much of use (?) \\
The closest SoC I could find quickly on the HP is [[http://www.ch-chip.com/Data/ch-chip/upload/file/20200904/AB5305B%20DataSheet.pdf|AB5305B]] \\
Just for reference: There is a [[https://www.cnx-software.com/2021/09/12/getting-started-with-bluetrum-ab32vg1-risc-v-bluetooth-audio-board-using-rt-thread/|getting started tutorial for RISC-V based AB5301A]]. \\
 
On the PCB of the FM transmitter you can add a socket for antennas (or solder directly) (there are pads, just cut the traces behind). \\
Fun fact: protective plastic sheet is on the 7 segment display (even though it is behind the casing) \\