Enviro+ / Ohms to PPM

Hi there,

have my Enviro+ up and running and set up a custom .py to read values and send them to MQTT. From there on I further use the values in openHAB (Smarthome).

My question is about the Enviro+’ MICS6814 sensor. Right now it reads…

  • 566 kOhm redu
  • 25k kOhm oxid
  • 369 kOhm NH3

Is there a chance to convert these resistances to PPM? I’ve stumbled upon a data-sheet (https://www.mouser.fi/datasheet/2/18/1143_Datasheet-MiCS-6814-rev-8-1144828.pdf) where there are diagrams for RS/R0 over PPM, but the RED sensor diagram only reaches to 10.00 kOhm on Y-axis.

Many thanks in advance!

The gas sensors seem to be totally dependent on air temperature, pressure and humidity so I can’t see how anything accurate can be read from them. I have two boards. On in my garage near Manchester current reads as follows:

This is in my lounge in Tenerife:

Ignore the flat section where my RPI crashed.

Hi @nophead, thanks for your reply.

I don’t have any issues with sensor data, just wanted to know if someone here managed to convert the Ohm’s to PPM.

Have a nice & KR!