Battery (3.7 V LiPo)
→ Toggle switch → Charger board VIN
– → Ground rail
harger Board (TP4056)
B+ → Battery +
B– → Battery –
OUT+ → Toggle switch output → ESP32 V+ rail
OUT– → Ground rail
Amplifier (PAM8302A)
VIN → 5V rail
GND → Ground rail
A+ → ESP32 DAC / PWM pin (audio input)
A– → GND
SPK+ → Speaker + terminal
SPK– → Speaker – terminal