JST Connector 1.25mm 8 Pin is correct. Just make sure you get the through-hole version. They also have SMD versions.
Does the default Airgradient v3 firmware that is installable via the web flashing on the v3 instructions page come with TVOC enabled in the code?
I tried connecting the SGP30 to the v3 pcb without the SHT30 connected and it still said TVOC: 0.
Yes it should work. Did you remove the pull up resistors on the SHT as per built instructions?
I haven’t removed the resistors yet as I was hoping I could test the SGP30 by removing the SHT30 first and only having the SGP30 connected.
Also, is there an updated link for the v2 basic diy enclosure 3d files? The link at The AirGradient DIY Sensor Enclosure does not work anymore.
It might work without the SHT but probably better to remove the pull ups and try.
By the way the SGP30 needs some warm up time so it’s normally that it’s 0 for a few hours. Then try to make some chemicals eg with ethanol to see if it reacts.
I will check the link for the 3d drawings tomorrow. We still have them but I updated the website recently and maybe a mistake happened.
Links should work now again.
Something went wrong removing those resisters. They are gone, but now I am not getting any readings from the SHT30. Temp and Humidity are 0 (via serial console).
I poked at it with a meter and I don’t see any shorts, but I’m trying to look up a schematic for that module so I can get a better idea what I’m looking for.
I’m having a hell of a time desoldering the parts from v2 for the upgrade kit… Anyone have any tips?
I’m fairly sure I’ve destroyed both S8s, both SHP30s, and both Wemos modules with too much heat. I really would just recommend buying new for anyone still considering taking this on…
i build the new kit today. works good! i edited the code quite a bit to get the measurements into prometheus.
i also have the old kit (the now basic) with a added sgp30 so i can compare those measurements with the new kit. they should be the same but with the different pcb and case they might be better.
i really like the larger screen. more info at once.
After fiddling with it a bit, I got the SHT30 module working again. I still see 0 on the tvoc sensor though. I will poke around with it more today.
I’m pretty sure I’ve destroyed my SHT30 when desoldering the pullup resistors, now although it can be detected on the bus, it only reports 0. On the plus side, TVOC is reporting fine now.
I really want to get temp and TVOC working. Is there an alternative temp/hum sensor that would work alongside the SGP30?
It is really a problem of the number of i2c devices on the bus and the esp8266 has only one bus.
You can try and find a temperature sensor that does not use i2c but I would rather recommend to get a new SHT and try again.
The TVOC sensor needs time to burn in. Then after a few hours you can use some ethanol and see if it spikes.
Just want to let you know that we are now selling the kits again in our online shop.
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is there any guides for Home assistant integration?
I’m using ESPHome.
I have the DIY Pro kit now for a week and had some trouble getting everything started. I tried the supplied arduino code just to test everything before I changed over to ESPhome to integrate it into HA.
Things I encountered:
- SHT31 immediatly died. No modifications like removing the 10k pullups. Not sure what caused it but I measured 12ohm between GND and SCL. Ofcourse the I2C bus doesn’t work then because its always pulled down and bus halts.
- To substitute the SHT31 I added a BME280 but put it in the 3.3v place. When both SGP30 and BME280 connected on the arduino code the I2C bus gets pulled down so nothing is working, no oled updates. This turns out that SGP30 doesn’t like the normal I2C bus speed and blocks the bus in my case. 50kHz seems fine for the bus and is fast enough for oled updates. All my sensors work stably now.
- Grabbed another SHT31 and removed the pullup resistors because the normal positions for it is on 5v which causes to pullup the bus to 5v and therefore causes issues with other sensors on the bus. In my opinion this is a design oversight to combine 3.3v and 5v on the I2C bus. Lots of information to not combine different voltages on I2C I learned.
- Having 3 sensors/oled on I2C bus with each 10k pullup and including internal pullup of the wemos is still fine and works on 100khz. The higher bus speed you need a stronger pullup(low combined resistance) but you shouldn’t exceed 3mA for a sensor to pull it down again for communication.
- Using ESPHome really speeds up tinkering with all settings and testing of these things. You can use it standalone with the webserver function enabled.
Thank you Hendrik for that valuable feedback.
Since we are shipping the kits now as a regular kit, I am closing this thread because it contains so many different topics. In case you have any specific problems, questions, etc. Please open a new discussion.