Control using an electronic relay.

The intent is to not only monitor, but to control. I dug a 20 year old electronic relay out of my junk box, added a resistor, diod, and extension cord. The hot side (small lug on plug) is split and attached to the power lugs of the electronic relay. The control side will attach to one of the WX175 TTL outputs.









The 3 amp 'relay' I used is out of production, when I find a replacement I will provide more detailed info. I do not want to send anyone off searching for an obsolete part. The diod is there to protect the optoisolator in case the control lines are reversed. It happens.

To test the unit I plugged my desk lamp into the extension cord, plugged the extension cord into the wall, and then applied 5v to the control side of the relay. The desk lamp lit.

The photo to the right shows the actual test. The unit is hiding inside the 2 1/4 PVC pipe with the extension cording protruding from the fron. The power supply just above it is providing the 5 volt signal voltage.

The unit needs an enclosure. I may drill a few holes in the PVC pipe for cooling, add a pair of caps and call it good.

This unit will be used to control the greenhouse cooling fan. The actual hardware will be safe in the garage with the output AC run from the garage to the greenhouse.

More to come...