Yes, connected to Raspberry Pi using this Python in a loop (https://github.com/UedaTakeyuki/mh-z19), it gives me values around 550, if I blow on it, it goes to 750, so it looks fine on Pi. One thing I noticed is that the "pin state buffer" page in tools is empty. Shouldn't it show the plug...

Thanks for the quick reply.
I tried just tried both:
HW Serial0 swap : GPIO-13 (D7) -- TX/GPIO-15(D8)--Rx

HW Serial0 : GPIO-3 (D9) -- TX/GPIO-1(D10)--Rx

And get same results around 5700.

Hi, I am using the MH-Z19B sensor to retrieve CO2 ppm values. The sensor is giving values over 5000ppm. It usually starts at 410ppm and after a minute, jumps to 5700. The sensor itself works fine as I can get correct values when plugged in Raspberry Pi. Usually between 500 and 700ppm. I am currently...

Hi, I am Nic, French but I have been living in the UK for the last 20 years.
I have recently been playing with the node mcu/esp8266 boards.
Love the espeasy mega, it does make things easy (or almost!). I was getting frustrated with Arduino ide and its compiling errors.