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Joined: Wed Sep 05, 2012 2:04 pm
Location: Ireland
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i2c 8 channel IO board with relays

Fri Mar 08, 2013 12:47 pm

Hi folks,

Thought this little project I've been working might be of some use..

I need a versatile IO board that I can hook up to an Arduino, Raspberry PI, Beaglebone or Carambola. All of which have an i2c bus. So armed with a MCP23017, I’ve come up with this IO board.

* 8 Relay outputs ( relays are spec’ed at 240V 5A )
* 8 Digital inputs ( switched input, closing to ground )
* Selectable i2c address ( up to 8 of these on the one i2c bus )
* All running from +5V ( relays can be powered from an alternative power supply if 5V coils are not to hand )
* Single layer, through hole construction ( old skool! )

You'll find more info at my blog: ... th-relays/, along with info for making your own PCB, KiCad and other bits-n-bobs.



PS: In the next rev, I'm hoping to add the interrupt line from the MCP23017 back into one of the GPIO pins. This will make reading the inputs a little easier.

Posts: 14
Joined: Fri Aug 09, 2013 9:04 am

Re: i2c 8 channel IO board with relays

Tue Jul 21, 2015 7:51 am

Thanks for sharing!

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