1.- Bluetooth HC-05. AT commands.
HC-05 Bluetooth modules contain an MCU.
It has PIO terminals.
Image from (Datasheet): http://kio4.com/arduino/imagenes/banggood-hc-05-manual-optimized.pdf
- I wanted to make the following montage. I soldered a wire to the PIO5.
I wanted to turn on the LED from the app using AT commands.
But it didn't work for me.
I tried other methods.