@Cybolord said in DHT-22 sensor outages in use with Homeduino:
So what is your recommendation about the capacitor (µF) regardinig noise and where should i place it (powersupply or dataline to DHT-22)? there is already an 10k resistor between the 3v3 and the data line…
My recommedation is to use a 100nF capacitor between Vcc and GND as sketched in the data sheet http://www.micropik.com/PDF/dht11.pdf. There are other sources suggesting other resistance values, but I haven’t tried that. The geneneral purpose of the capacitor is to smooth the supply on demand and to decouple high frequency signals, noise, from entering or leaving the circuit.
As far as I know the pull-up should be 4.7k assuming a cable length of less than 1m. For longer cable lengths it must be even lower. The 10k may be ok, though.
btw: there is also another DHT-22 running without any outages! possibly another Hardware rev.?! one is connected to PIN12 of Arduino and the other one to PIN11…
The DHT-22 is a different circuit than DHT-11. It should also be said that there are really cheap makes of DHT sensors being offered which may have quality issues. If you paid less than 1 EUR for your DHT-11 sensor you probably should get another one for testing …
My recommendation is not to use DHT-xx sensor unless you have good reasons to do so (e.g. you want use 1wire for infouse cabling of sensors). Personally, I have made good experiences with SI7020 I2C sensors.
"It always takes longer than you expect, even when you take into account Hofstadter's Law.", Hofstadter's Law
so you may be right…