FEZ-Relay on EMX development board?


I tried to connect the FEZ-relay to any of the 3.3V IO on the emx development board. However I cannot get the relays to trigger. I had to disconnect the connector as the emx development board does not have the right sockets. What signal has to be connected to each of the wires? red/black/green?

Do i need to use the Fez_component_relay drivers? or can i just switch an EMX OutputPort?


The relay cable consists of 3 items:

A high signal will switch the relay on, a low signal will turn it off.
You can just set the state to true or false.

Color codes of the cables are:
Red: +5v
Black: GND

Where the connections are so that the signal is between the +5v and GND.


I connected it with help of your pointers! I can now correctly trigger the relays!

Is there a schema available for the Fez-relays. I mean what components are used. So maybe I can have them custom made. For when they might not be available for sale anymore.

Thanks again.

You’re welcome. That’s what we are here for ;D

There are, as far as I know, no schemes of the components online. However, it’s not hard to make.
You will need a relay (of course ;D )

GHI uses this one: (any 5v relay (or more if you like) will work. It depends on your needs)

You will then need a transistor (for “switching” the relay with a IO - I like to have things safe :stuck_out_tongue: ), some diodes (protecting your board) and some resistors.

If you need some inspiration or some more understanding sparkfun has a relay PCB

Good luck :slight_smile: