why do you think some spikes are expectable? I run a SDM300D2 and a CCS811 in the same room. Home Office of two Humans, window open 2-3 times a day. The CCS811 has a configured base line and a moving windows average of 5 but 10s intervall. The SDM300D2 is new and raw data and default values.
The temperature (blue dots) on the secondary axis are just for reference (window was open). I’m not sure which one should be more accurate. SDM300D2 has much smoother measurements but was never above 1000ppm what I can hardly believe. on the other hand, the SDM300D2 makes more sense when the window was open (ppm goes down). a shorter time range explains this a bit better:
The CO2 output from the sm300d2 is not a real reading, meaning its not like how the Senseair S8 measures co2 for example. sm300d2 outputs eCO2 where e stands for estimated. it is a calculated estimation of co2 using the TVOC sensor. This is based on the assumption that the VOC produced by humans is proportional to their exhaled CO2. For example, if you use a spray that has VOCs but not much of CO2, the eCO2 sensor would be way off. You should never use the sm300d2 for CO2 measuring. It does not have a real CO2 sensor inside. Senseair S8 co2 sensor, seems to have the best price/performance ratio. Use that instead for CO2 measuring. Also I couldn’t find any reviews about the VOC metering performance of sm300d2. So I would appreciate if ppl here would share their experience with the TVOC measuing of the sm300d2. Does anyone know if the TVOC sensor Is any bettter than the el-cheapo MQ series sensors? I’m guessing the particulate sensor is same as the PMS5003.
I was about to make my own post but see @sender and @TobiasGJ have the same issue. SM300D2 CO2 sensor returns to 400 ppm and never gets above 500 ppm, even after leaving it outside for an hour.
Guess I’ll have to get an SCD30 to complete the air quality sensor ESP
