Users of the Velleman K8055N (VM110N) I/O card coupled with the K8056 (VM129) will know there are only 8 relay outputs but by adding this circuit you can make use of the DAC1 & DAC 2 to give you two more relay outputs driven by the analog outputs. Connection of the relays directly to the Velleman I/O card did not work so I used a transistor that’s switched by the I/O DAC output and let this operate the relay.
The photograph of the little circuit board I have put together has a 5 Volt regulator also to drop it down to 5V as I am using a 5V relay.
Operation of these two extra relays are done through the Viking program.
My unit operated on a DAC output of 3 Volts (you could alter the value of the 10K resistor but it worked)
I am putting this out there as one solution to adding more output to your Velleman I/O unit - please be careful with the soldering iron and make sure you are happy with what you have built before connecting it all together. Don’t shoot the messenger.