Picked up a CJMCU-811 CO₂ and air quality sensor to compare it with my go-to MH-Z19B. It’s smaller, cheaper, uses I2C, and reacts super fast (you can literally breathe on it and watch the values change). One of my two units didn’t work, though—so quality might be hit or miss.
In Part 2 of my CO₂ sensor project, I set up the MH-Z19b with Arduino and ESP8266 using PlatformIO. Added WiFi-based configuration with my own WiFiConfig library, and used RecurringTask to keep everything responsive without blocking the loop. It’s simple, wireless, and super easy to tweak from your browser!
Ever feel like the air in your room gets a bit… stale? I picked up a cheap MH-Z19b CO2 sensor and built a simple home air quality monitor using an ESP8266 and some DIY magic. Here’s how I prototyped it (twice!) and got it up and running with WiFi and colorful LED alerts.