Build an Arduino-based humidity and temperature meter in just one day and for just $10. This design uses the Si7021 humidity and temperature sensor, a 128x64 OLED display and a clone Arduino Uno.
PLEASE NOTE: Adding the level shifter board is COMPLETELY UNNECESSARY as the little GY21 PCB already has these components onboard. My bad 🙁
https://www.silabs.com/Support%20Documents%2FTechnicalDocs%2FSi7021-A20.pdf
PLEASE NOTE: Adding the level shifter board is COMPLETELY UNNECESSARY as the little GY21 PCB already has these components onboard. My bad 🙁
https://www.silabs.com/Support%20Documents%2FTechnicalDocs%2FSi7021-A20.pdf
You’re breathing on it the whole time. The others read from the back.
do you have tutorial for the automatic switch on/off using hygrometer sensor ?
I am planning to make a 3d printer filament enclosure and since I don't trust either the cheap sensors, it came to my mind to look for another sensor and here I am, I would like to know if someone can help if this can be managed to be more compact or done via another platform other than Arduino like ESP… just to make the whole thing as compact as possible.
what about the DHT22 sensor? do you recommend it?
What is this thing you call "humidity", i have never heard of such a thing living in southern Arizona
Relative humidity and temperature scale at the, roughly, 1 degree C = 5% RH … physics, not manufacturing error …
Hi, thank you for the work involved, I have had limited success so far. I provided the 3.3V from the arduino, and tried taking the scl and sda through 5 to 3.3 level shifter but got nothing on the serial monitor. I took the scl and sda direct to the sensor and got results of a kind on the s monitor. the humi was looking good and responsive to just blowing on it. But the temp was a constant 128.87 which is somewhat erroneous. oh dear, back to the drawing board !
sht21 is +-2 for RH, sht25 high +-1.8, sht35+-1.5. Caliber4r is a 1% hygrometer, but not sure which sensor that one uses. Those cheaper ebay humidity meters are garbage, and use just a pcb trace for a sensor and a cheap coating to absorb moisture. The other cheap ones use a coil for rotating a needle which is also garbage. The acurite hygrometers use the sensirion sensors with +-2 RH. Boveda sells a calibration kit for 7 bucks and is better than using salt.
reading of si7021 is perfect
I used it in many many projects
I'm getting negative humidity, like -47% but the value changes. Is it possible I got a sensor with broken calibration?
Does anyone else have issue with that SI7021 reading 128.87 degrees celsius? But it reads humidity. Of course it's way too low because that high temperature.
Shouldn't you remove the protection sticker blocking the opening on the chip, so air can get in?