I bought 4 JDY-40 modules from AliExpress but they don't work as expected.
These are 9600baud serial Uart modules with a range of 120m
All I see on power up from TxD is "START" which makes me think that there is no Firmware loaded and the bootloader is waiting for some code.
I have done a lot of Google searches and even asked the AliExpress supplier for help... No success. Dispute time has finished.
The chip on board is a BK2461.... I have searched for Firmware on this chip too. Have yet to check out the bootloader procedure.
I have ordered some more JDY-40 modules from another supplier on AliExpress... Some weeks away....
If they work I may be able to pull the code out and install it on the first batch.
Any help would be most appreciated.