The BLUE wire and the GREEN wire

[Tman]

At 20ma ....i think you got the solution !
http://www.ebay.com.au/itm/Mini-1-Ch...item461ad3e7fa
I found this cheapy , is it working on the same principle ? they say TTL source for the signal , i guess it needs
another source (5volts) to trigger the relay ....not very familiar with Arduino system.

Thanks Tman - will let you know

This is also quoted in the ebay text ;