ESP32-C3 Power Alarm

Complete Technical Schematic & Firmware Logic

1. Wiring Diagram

Voltage Divider & I2S Configuration
5V Power
Ground
Audio Data (I2S)
Mains Sensing (Divider)

2. Bill of Materials (BOM)

Component Model / Specification Role Est. Cost
Microcontroller ESP32-C3 SuperMini (RISC-V) Main Logic & Audio Storage $2.10
Power Supply 18650 Battery Shield V3 (Always-On) Uninterruptible Power (UPS) $2.50
Amplifier MAX98357A I2S Class D Digital Audio Decoding $1.60
Speaker 4Ω / 8Ω 3W Cavity Speaker Audio Output $2.00
Passive Parts 1x 470µF Capacitor, 2x 10kΩ Resistors Power Smoothing & Sensing $0.25
TOTAL ~$8.45

3. Firmware Event Logic