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Humidity Sensor

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Active Member
Hi guys... I've looked around and found a way to get a low cost humidity sensor using carbon resistors with the coating removed. My question is that:
1. What is the suitable range of the resistance of the resistor that I should choose?
2. Should I use a wheatstone bridge or just a voltage divider to get the output voltage corresponding to different humidity levels? I'll be feeding the input into an ADC in a PIC.



Well-Known Member
A low cost humidity sensor can be canibalized from a defunct VCR, and if has manufacturer markings, some data sheet can be obtained for your application.
DigiKey sells them too.


New Member
the lowest cost possible for a humidity sensor is a match with a wire at each end ...
you have to measure some samples, but it is very reliable
althought it is not very precise...
just put another big resistor in serie with it, and measure the voltage at the second resistor with the adc of the pic . so simple.
depends on your application...
out of that I like the sensirion sensors (shtxx)
they are not cheap (around 15 euros each) but are very precise, and very easy to interface, no adc needed it is all digital with a sort of i2c bus.


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