Homebuilt ROVs Forum

I'm testing my two K8023 kits and I can't get them to activate the relays. The individual channel LEDs light up, but no relay action. I've tried both kits.
Have I set this up wrong?

Not sure about the rest of your wiring but it looks like the relay is connected to one of the 10 Open collector outputs - this means that the Velleman K8023 will sink current down one of these 10 outputs not supply it.

So the relay must be connected to a +ve voltage and the other side of the relay connected to one of the outputs.

It looks like you have one side of the relay connected to GND which means you have no voltage on the relay when the open collector output is on.

Take note that the open collector can withstand 50V at 100mA only, so 5V and 12V up to 50V are OK but the relay must be able to switch with less than 100mA current. Look at your relay specification, it will tell you what the coil switching voltage and current are.

I believe Oldsirhippy is right, just move that one wire from the ground over one spot to the +Vext and I think you'll be good to go.

-Steve

Thanks guys. I moved the green wire from the board to the battery + and it works perfectly.