ESP32-C6 E-Paper Air Quality Monitor

A high-precision, open-hardware environmental monitor designed to track CO2, Temperature, and Humidity levels. The device is built around the RISC-V based ESP32-C6 and features a raw E-Paper panel with a custom-designed boost driver to ensure zero light pollution and minimal thermal self-heating.

Key Features

• MCU: Espressif ESP32-C6-Mini-1 (RISC-V, Wi-Fi 6, BLE 5, Zigbee).
• Sensors:
  • SCD43 (Sensirion): Photoacoustic NDIR CO2 sensor for high-accuracy indoor air quality monitoring.
  • SHT45-AD1F (Sensirion): Ultra-high precision (±1.0% RH, ±0.1°C) temperature and humidity sensor with integrated PTFE membrane for protection.
• Display: Pervasive Displays E2266QS0F1 (2.66" E-Paper/E-Ink).
• Power: USB-C powered via a high-efficiency, low-noise LDO (TLV75733). Designed for continuous operation without batteries.

Engineering Design Decisions

This project involved several specific hardware design challenges:

1. Thermal Isolation (Mechanical/Electrical): To prevent the heat generated by the MCU and voltage regulators from biasing the sensitive SHT45 and SCD43 readings, the sensors are physically isolated on the PCB using milling slots (thermal cutouts) and thin connecting bridges.
2. Custom E-Paper Driver: Instead of using a pre-made display module, I integrated the high-voltage boost converter (generating ~15V) directly onto the main PCB using a specialized power inductor ($I_{sat} > 800mA$), N-Channel MOSFET, and Schottky diode topology.
3. Signal Integrity: The schematic includes specific filtering for the photoacoustic sensor's peak current demands and a dedicated boot-strapping circuit to ensure reliable flashing via the native USB interface.

PCB Layout & Thermal Engineering

The design utilizes a 4-layer stack-up to ensure solid Ground return paths and stable power delivery for the ESP32's RF radio.

A dedicated thermal isolation slot separates the board into two distinct thermal zones:

• Right Side (Hot Zone): Contains the ESP32 MCU, Power Regulation, and Boost Converter.
• Left Side (Cold Zone): Contains the environmental sensors, connected only by narrow FR4 bridges to minimize thermal conductivity.

Status

• Schematic Design & Verification
• PCB Layout (4-Layer)
• Manufacturing & Assembly

License

MIT License