Hello, a newbie here. Apologies in advance if i am posting on a wrong forum.
I recently purchased/configured a SCD41 for a project that needs to monitor CO2 readings in a grow house. I got it configured and it started showing data in HA. I noticed a white sticker on the top sensor (see attached as a ref ). I was like ohh a protectant…took the tape off. Tiny hole underneath. CO2 readings went down to Zero(0). I freaked out. There was still some stickiness left so i put it back.
Please help. Is it supposed to stay on or peeled off? and need to stay on… did I mess up? I see readings again. But are they valid?
I don’t see any mention of it on sparkfuns page, but the datasheet for the sensor includes ‘Note that the white protection membrane on top of the sensor must not be removed or tampered with to ensure proper sensor operation’.
So it’s probably be best to leave it on there.
It’s only a guess, but it’d have to be some kind of permiable membrane, and removing/replacing it probably wouldn’t change an awful lot.
I’m not sure how to check if it’s still accurate, without either comparing it to previous readings or a known concentration sample.
If it’s giving readings that aren’t miles different, I’d guess it’s probably still OK for a grow house (That likely wont need perfectly accurate absolute measurements, more rough/relative readings?).
Shame it can’t be used to measure CO2 conentration in water, or it could be really useful in an aquarium I’ve got that I pump CO2 into
There may well be others around on here that have used them (I haven’t), but asking in any forum sparkfun have, or their support (if that’s who you got from) might be more obvious places to get some solid info… 'cos it’s not really a question about esphome.
Thank you so much. You are correct…I am after an approximate reliable reading (if thats a thing). I placed the sensor next to a netatmo room sensor and the readings only differ by around 65 ppm. Netatomo is not a solid benchmark…but good enough for a grow house. However, temp is definitely off. I need to research that further.
You are correct. Not an esphome question. Thanks for pointing in the right direction
I only skimmed over it, but calibrating the sensor is mentioned in that datasheet.
If it changed after the white thing was taken off and put back on, that might set things straight?
I was able send the calibrate command. I read somewhere …do it outside and leave it there for few hours. It will soon join several other sensors in the grow room. A techie who recently took gardening as a hobby…not a good combination. lol
Interesting. I have a SCD41 from Amazon, and I’m getting accurate-ish temp/humidity readings, but Co2 is stuck at zero. It has not gone above 0 once. Found this thread, and noticed the white thing is already removed. I wonder if Amz sent me a previously returned device. Ordering a new one.
