Instead, he drew up a simple schematic that used an Arduino Nano, an FM radio module based on the TEA5767, and an audio amplifier based on the LM386. A single button on the Arduino helps cycle ...

along with a low-cost condenser microphone with a transistor-based preamplifier and an LM386 op-amp for the speaker circuit. In the ESP32 module the built-in DAC and ADC are used for audio in and ...