Hello
Im using a DHT22 temp and humidity sensor which is working without a pull up resistor. Since building it, I’ve noticed a bunch of different projects using a 10k/4.7k pull up resistor.
Is this needed. Some sources say a resistor is built in and some say it is needed. I can’t seem to find solid info on why it’s needed.
If I use a 10k resistor, what will differ? Or is it to sustain the correct voltage level.
Apologies as I know there loads of info out there but some info is conflicting.
Cheers
I find the DHT22 to be more reliable (less prone to noise problems) with a pullup. 10K works for me.
groundFungus:
I find the DHT22 to be more reliable (less prone to noise problems) with a pullup. 10K works for me.
Brilliant.
Will the values decrease without a resistor?
I would suggest you to use Pull-up resistor with DHT22 in your project. In some cases when there's no output value from the sensor then this pull up resistor will provide +5V and the system won't get any random values or noise.
I hadn't realised the DHT22 sensor which I purchased differed from the regular model. The difference being is that it's mounted to a breakout board, having three pins rather than the four as standard. I am assuming this has a pullup resistor built into the board, which is why the results I got appeared 'normal'.
That sound about right?
