PLease Help Noob Control The Switch On My Specific Fog Machine

Hello everyone!

I'm a noob to electronics and Arduino in general, but I'm trying to learn by putting together a couple of "tricks" for Halloween. Currently, I'm trying to put together a "Monster in a Box" trick by specifically following the tutorial linked bellow:

My question here is that I need to control a cheap Mega-Lo-Mart type fog machine so it goes off with a puff of fog at just the right moment. I have the circuit built, and I have the Arduino controlling a relay switch as per the instructable above. However, the author of the instructable only adds the following as far as wiring up the fog machine to the relay. He writes:

"To control it with the Arduino I opened the receiver and soldered two lead lines to the trigger button pads. This provided me with lines that I connected to an Arduino controlled relay channel. It was a simple hack that I learn by watching a few YouTube videos. "

OK, so I searched online and YouTube and indeed I found a few examples of people controlling fog machines with an Arduino and a relay, but everyone I saw is making use of an external wired remote on the fog machine. My particular machine doesn't have that kind of wired remote, it specifically has an IR wireless remote, and it has a physical (Momentary??) switch on its case. Once warmed up, if I press the momentary switch just quickly I get a very short puff of fog, which would be perfect for my project. Holding down the button results in the machine producing fog for as long as the button is held down (up to 10 or 15 seconds; the max the machine can fog before having to reheat). Pressing the button on the IR remote results in the machine puffing for about 10-15 seconds, if it helps to know that.

I'm pretty sure it's possible to exploit that physical momentary switch using the Arduino controlled relay, but being new to electronics, and since this appliance has 120AC, I would really, really appreciate some help figuring out how to make this work. I think one of the three wires coming out of the switch (red, black, white) would need to be spliced and connected to the relay, but I'm not sure which one or how to test for the correct line. I have included a link to the fog machine I have, as well as pictures of the "guts" of the machine. Please, if someone could help me SAFELY figure out how to get my fog machine to cooperate with the instructable I link to, I would be very, very appreciative!!

Additional potentially useful info: I was able to disconnect the three wire connector on the switch circuit board, and even without that switch when the machine is plugged onto 120AC, it does indeed get hot and basically ready to puff.

Thank you in advance for your help!


Some photos of the machine; please let me know if you need any other info and thank you again for your help!




How to post images. There is no minimum number of posts to post images that I know of.

How to post images. There is no minimum number of posts to post images that I know of.

Yes, thank you, I had the wrong link to the photos, but I believe it's fixed now. Thank you for your help!


Just an update, I am not sure if all my photos are coming through, but basically I realized that the mechanical switch in question is just that, a simple mechanical switch. Because it's mounted to the board that also has the wireless IR receiver and corresponding electronics, that switch seemed initially more complicated than it really it. Simply put, I mustered up some courage around the 120AC and I disconnected the three prong connector going to the switch/IR receiver board on my machine, I plugged the machine in and waited until I heard the temperature switch click indicating that the machine was hot and ready to produce fog. Then I carefully shorted the red and black leads that were going to the switch, and POOF! Instant fog! So it seems that wasn't so complicated or intimidating at all.

I am going to proceed by connecting the red and black switch wires to my relay as I've seen in other YouTube videos, etc. However, if anyone sees this and thinks this is a bad idea, I'd appreciate it if you could let me know :wink:

Thank you to everyone for stopping by!