README.md

diy-co2-monitor

DIY, low cost esp-platform based CO2 monitor ;-)

This project is under development!!!
Current release should work for real-time CO2 monitoring 'out-of-the-box'.

This repository contains the firmware source code for a low-cost CO2 monitor built using platform.io framework, and standard ESP modules such Wemos Lolin32 and clones.

Current hardware setup, includes support for (total cost about 22€):

• Wemos Lolin32 OLED Board and clones (ESP-WROOM-32).
• MH-Z19B CO2 Sensor (0-5000ppm +/-50ppm range).

Features

• Realtime CO2 level (ppm) monitoring.
• 60 points historical data graph (with configurable average time).
• More coming soon...

Sensor wiring

As the ESP module is able to run supplied from standard USB Smartphone charger, it is only need to wire 4 cables between ESP module and MH-Z19B Sensor:

ESP module	MH-Z19B Sensor
5V	Vin
GND	GND
PIN 25	Tx
PIN 26	Rx

Compile and run

• Install Visual Studio Code.

• Install platform.io plugin.

• Clone (or download) this repository.

• Open folder with Visual Studio Code.

• Wait to platform.io plugin to load.

• Click on Build button (platform.io lower toolbar V) and wait until === [SUCCESS] === banner appears.

• Connect board to computer using a USB cable (in Windows 10, drivers will install automatically).

• Press and keep pressing tiny Boot button located on the rear side of the PCB.

• Click on Upload button (platform.io lower toolbar ->).
• Keep pressing tiny Boot button until Writing at 0x00001000... (100 %) line appears, and then release it.

• Wait until the firmware upload is finished, program will boot automatically.

Where to get parts (I have not any relation nor benefit with these shops)

Wemos Lolin32 OLED Board (clone):

• Aliexpress searching for ESP32 ESP-WROOM-32 OLED.

MH-Z19B CO2 NDIR Sensor:

• Aliexpress searching for MH-Z19B

MIT License.