FM modulation in FM transmitter
Test each part individually.
Feed the LM386 output to an audio detector (high impedance earphone, oscilloscope, &quot;line in&quot; on a PC, whatever). Can you hear it and does it get louder when you turn up POT1?
No?
Try biasing the mic capsule properly (like a 2K resistor to +3V3) and see if that helps... You might want to clean up the 3V3 supply for the purpose...



simulate this circuit &ndash; Schematic created using CircuitLab
The purpose of C3 is to keep DC bias away from the pot, which would otherwise cause crackling noise as the pot was turned.