With Halloween upon us I wanted to share my recent success story integrating a Fog Machine with ST. I’ve always wanted to create a ‘smart’ fog machine that I could integrate with the rest of my Halloween decor, with the ultimate goal triggering the machine on motion. I’ve seen projects on instructables using a localized PIR to trigger the machine but felt they were ‘lacking’ because it effectively required the guest to be in the vicinity of the machine to trigger.
I currently use ST for the automation of my exterior lighthing (among other things) and automate that lighting using several Monoprice ZWAVE PIR placed under the eve’s of my home in strategic locations. The goal; leverage my existing motion detectors to trigger a inexpensive fog machine, while still retaining the original control mechanism in the fog machine.
First up purchase the fog machine. I ended up getting this unit for $35 https://www.amazon.com/1byone-Halloween-Machine-Control-400-Watt/dp/B00F2ATEDC plus a gallonew of fog juice for $15.
Next up controlling the machine with ST. A Zwave relay wired into the trigger circuit seemed the way to go. Fog machines are generally controlled with wired ‘remote’ that will only operate once the machine is hot enough. A red light on the remote will illuminate when ready. The wired remote did not have enough space to add a relay directly to it, so I cracked the case on the fog machine where I found plenty of room.
Once inside I realized that the remote was opening the circuit between the juice pump and neutral after the load. Okay simple enough, wire my relay into the device hot and neutral, and add the switched circuit in parallel with the existing remote. This would leave the originally remote intact, provide some kind of manual control, as well as retaining the status feedback on the remote. I addition the device was registering on the Zwave network as long as the machine was plugged in, but the trigger would only work when the machine was hot enough.
My first attempts at this failed as while I could get the machine to trigger from ST, the trigger would operate at any time, even when the device was cold. I realized that I need a dry contact relay to make this work. Most of the Zwave micro relays are wet contact meaning that voltage is present on the switched circuit even when in the off position. I just happened to have a linear zwave relay let over from another project. https://www.amazon.com/GoControl-Z-Wave-Isolated-Contact-Fixture/dp/B00ER6MH22. I would actually recommend one of the other true dry contact relays as the linear relay was a bit bulky for the fog machine.
After I wired in the new relay I was able to turn the machine on/off remotely. Now integrate the machine with the PIR’S. Using CoRE I was able to create a piston that turned on the fog machine for 30 seconds after the monitored PIR’s changed its state to active.
That’s about it.