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silverzpeed
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Joined: Thu Jul 17, 2014 11:58 am

Help with reading 12VDC on GPIO

Thu Jul 17, 2014 12:03 pm

So here is what I am trying to do. I have a PID that has a 12VDC SSR that connects to small fan. Im wanting to add a raspberry pi to the design of my project and would like the Pi to be able to determine that power was supplied to that 12v line.
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mikronauts
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Re: Help with reading 12VDC on GPIO

Thu Jul 17, 2014 1:57 pm

You need a voltage divider...

See

http://en.wikipedia.org/wiki/Voltage_divider

http://www.raltron.com/cust/tools/voltage_divider.asp
http://Mikronauts.com - home of EZasPi, RoboPi, Pi Rtc Dio and Pi Jumper @Mikronauts on Twitter
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silverzpeed
Posts: 2
Joined: Thu Jul 17, 2014 11:58 am

Re: Help with reading 12VDC on GPIO

Fri Jul 18, 2014 12:09 am

Thats great info. I have read that the voltage across the GPIO pins cannot be higher than 3v DC is that correct?
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FLYFISH TECHNOLOGIES
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Re: Help with reading 12VDC on GPIO

Fri Jul 18, 2014 12:22 am

Hi,
silverzpeed wrote:I have read that the voltage across the GPIO pins cannot be higher than 3v DC is that correct?
No.
The correct value is 3.3V DC.


Best wishes, Ivan Zilic.
Running out of GPIO pins and/or need to read analog values?
Solution: http://www.flyfish-tech.com/FF32
ame
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Re: Help with reading 12VDC on GPIO

Fri Jul 18, 2014 12:44 am

mikronauts wrote:You need a voltage divider...
You would be better off with an optoisolator.
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