CO2-TVOC-Sensor

A sensor to report carbon dioxide and volatile organic compound levels to MQTT and an ESP32's display

Functions

Currently the firmware has the following functions:

• Browser based WiFi configuration.
• Reporting of CO2, TVOC, temperature, humidity, pressure, PM1, PM2.5, and PM10 values to Display
• Reporting of values to MQTT
• Setting CCS811 baseline (automatically and manually) and restoring it at boot

Hardware Requirements

ESP32 with OLED Display.

The code has been written for and tested on a Heltec WiFi LoRa 32 (V2) but should also work on the cheaper WiFi Kit 32. Since the code makes use of Heltec's Arduino library to access the Display, hardware Support is currently limited to their devices.

CCS811 Sensor

To measure carbon dioxide and volatile organic compound levels a CCS811 Sensor is being connected through I2C.

BME/BMP280 Sensor

To set the environment variables of the CCS811 we need a data source for temperature and humidity. The BME/BMP280 sensor provides this data.

g_bme_humidity = bme.readHumidity();
g_bme_temperature = bme.readTemperature();
ccs.setEnvironmentalData(g_bme_humidity, g_bme_temperature);

Optional Hardware

PMS5003 Particle Sensor

A PMS5003 particle sensor can be connected to read fine dust values PM1, PM2.5, and PM10.

Connections

The connections are:

Heltec WiFi LoRa V2:

ESP32   -   CCS811  -   BME/BMP280
==================================
GND     -   GND     -   GND
3.3V    -   VCC     -   VIN
4       -   SDA     -   SDA
15      -   SCL     -   SCL
3       -   WAKE

ESP32   -   PMS5003
===================
22 (RX) -   5 (TX)
23 (TX) -   4 (RX)
GND     -   2 (GND)
5V      -   1 (VCC)

Heltec WiFi Kit 8

Attention: Check the WiFi Kit 8 Pinout Diagram to find the correct PINs. What's written on the NodeMCU is most likely wrong!

Currently this device has not been tested successfully.

ESP8266 -   CCS811  -   BME/BMP280
==================================
GND     -   GND     -   GND
3.3V    -   VCC     -   VIN
GPIO4   -   SDA     -   SDA
GPIO5   -   SCL     -   SCL
GPIO14  -   WAKE

Software Requirements

Compilation and Development

• Visual Studio Code
• PlatformIO
• The libraries listed in main.cpp installed

Reporting

Must have:

• MQTT Broker (e.g. Mosquitto)

Optional for storage and visualization of long term data:

• Node-RED
• Influx-DB
• Grafana

What is there to improve? / Open Tasks

• Designing the firmware's integrated webpage
• Showing WiFi- and MGTT-State on OLED
• Supporting more OLED screens and other ESP32 and ESP8266 devices
• Code documentation
• LoRa/LoRaWan support
• Internationalization / translation

Your help is appreciated! Like to become a contributor?