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Humidity Sensor (5.8V)


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#1 seascan

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Posted 21 December 2011 - 08:27 PM

Hi. I have ordered the following: http://www.sparkfun.com/products/9569 humidity sensor. The output goes to a maximum of 5.0V which exceeds the Ain of the Netduino. I was thinking of a voltage divider. Is this the best way to handle this type of situation? Where the sensor output is connected to ground through a 5K and 10K in series (at the Ain is connected to the middle of the two resistors)? P.S. Topic should read (5.0V)

#2 Valkyrie-MT

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Posted 21 December 2011 - 09:07 PM

Hi. I have ordered the following: http://www.sparkfun.com/products/9569 humidity sensor. The output goes to a maximum of 5.0V which exceeds the Ain of the Netduino.

I was thinking of a voltage divider. Is this the best way to handle this type of situation? Where the sensor output is connected to ground through a 5K and 10K in series (at the Ain is connected to the middle of the two resistors)?

P.S. Topic should read (5.0V)


I think you'll find your answer in this thread. But, the short answer is skip the voltage divider and just connect your sensor to 3.3V instead. It's out of spec for the HIH-4030, but by all accounts, it works fine. DO NOT connect 5V+ to your Analog In. I have fried a few of my Analog In's this way :(

-Valkyrie-MT

#3 seascan

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Posted 21 December 2011 - 10:27 PM

Thanks Valkyrie. That solution looks easier.

#4 seascan

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Posted 22 December 2011 - 09:54 PM

Valkyrie, How can you tell if an Ain is fried? Does it no-longer function at all or does it just give bad readings?

#5 Spork

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Posted 22 December 2011 - 11:59 PM

Valkyrie,

How can you tell if an Ain is fried? Does it no-longer function at all or does it just give bad readings?


What does it read if you jump 3V3 to it?

#6 seascan

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Posted 26 December 2011 - 02:36 PM

What does it read if you jump 3V3 to it?


Hi Spork.

It is reading the level correctly. The weird thing is that it seems that a reading on one channel effects the others. I have noticed this with a light sensor and now with a humidity sensor.

A week or so ago I accidently had 5V into an analog channel... that is why I am wondering if I boogered up the Analogs and that is causing this strange behavior.

I am using A4 and A5 as SCL and SDA for a serial temperature sensor. My humidity sensor comes into A2. If the humidity spikes then I lose the serial until the A2 drops. I noticed this behavior on all the channels.




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