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2021-01-24 8:34 pm
Hi This is my first query re my first project which is to use a DHT22 sensor to check the temperature. I am aiming to use it to switch on 12v at a given temp with a relay. No problem recording the temp or working the relay but if I use them together I get nan readings on the temp. As soon as I disconnect the relay the temp readings re-appear.
Ive tried various output pins with no success. Can someone give me some guidance please?
2021-01-24 10:41 pm
@r_hood, nan error is 'not a number' error. It sounds like something might be interfering with the I2C buss you have set up. Without visual or hands on, that's my best guess.
2021-01-24 10:45 pm
Try ignoring the sensor data and manually control the relay in the code. Try to isolate/separate the two and see if you can locate the problem.
Edit: Try to work with both separately and it might highlight the problem.
Centari reacted
Topic starter
2021-01-25 5:11 pm
Thanks Centari and Yurkshire Lad
I think I’ve got things sorted now. Not sure what I did re the ‘nan’ problem but it’s working now - possibly a bad connection?
Re the relay itself I found a fault with it. It’s an optorelay module and was indicating by the LEDs on the input side that it was responding to input from the ESP32 but I found it needed a good thump to make the output switch over ! I’ll perhaps set it up on the blink program to see if that will loosen it up.
Thanks for your time, much appreciated