Read humidity from a humidity sensor module

Other Hardware Sensors
1

Hi everyone :slight_smile:

I need help with the analog reading from a humidity sensor module, this board has a LM393 voltage comparator and a HR202 sensor, i don't have a datasheet of module, but i have a datasheet of HR202 sensor here http://www.elecrow.com/download/HR202%20Humidity%20Sensor.pdf, please someone can explain me how this works? How to convert the analog output to the humidity percent? I supposed with the table at the datasheet can calculate the value, but i don't get it how doing that, here http://www.ardobot.com/media/catalog/product/3/b/3ba2f1ed7104e9b054c6791fe05d24c6.image.998x666.jpg are a picture of the sensor module, i hope someone can help please :confused:

2

I always look first if other people have already have done something wih that sensor by entering "HR202" in the search box on top of this page.

Here's one thread:

http://forum.arduino.cc/index.php?topic=143815.0

Leo..

3

Wawa:
I always look first if other people have already have done something wih that sensor by entering "HR202" in the search box on top of this page.

Here's one thread:

HR202 Humidity Sensor - Sensors - Arduino Forum

Leo..

In that topic, someone posted a code to reading the humidity, but i need a explanation of how it is works, i do not get it, for that is my question.

4

It's a polymer based resistive humidity sensor.
You can find one inside every old VCR against the drum base, to sense condensation.
Other equipment that is sensitive to condensation (cameras?) might also have them.

They need a <=1volt 1kHz AC measuring voltage. DC will quickly destroy them (metal migration).
I doubt that that module is using an AC measuring voltage.

I published a bathroom fan circuit a few years ago in an elecronics magazine for this sensor with 555s.
Elektor Jan/Febr 2013.
Leo..

5

Wawa:
It's a polymer based resistive humidity sensor.
You can find one inside every old VCR against the drum base, to sense condensation.
Other equipment that is sensitive to condensation (cameras?) might also have them.

They need a <=1volt 1kHz AC measuring voltage. DC will quickly destroy them (metal migration).
I doubt that that module is using an AC measuring voltage.

I published a bathroom fan circuit a few years ago in an elecronics magazine for this sensor with 555s.
Elektor Jan/Febr 2013.
Leo..

Oh i get it, thanks, exists a equation to calculate the relative humidity by the voltage output of the sensor module? Or exists some Arduino library for this sensor module?

6

I woudn't use this simple resistive sensor as a RH sensor.
It is better suited as condensation sensor.
Perfect for an automated bathroom fan where RH is in the range of 80-100%.

RH also needs an integrated temp sensor.
Try something like the DHT22.
Leo..

7

Wawa:
I woudn't use this simple resistive sensor as a RH sensor.
It is better suited as condensation sensor.
Perfect for an automated bathroom fan where RH is in the range of 80-100%.

RH also needs an integrated temp sensor.
Try something like the DHT22.
Leo..

I have one temperature sensor