Fog Machine - On Command

Question

I work with a marching band, and we want to use fog machines for a particular part of the show. I know how to code/program in Arduino, however I am not great in the electrical and technical end. I own two fog machines, and the issue is that we need them to start fogging on command without delay (at least not a long delay, just not early and not late). We cannot exactly stop the show in the middle of a competition to say "wait, the fog is coming soon." We also need them to stop fogging on command.

I have read this article, Motion Triggered Fog Machine and it seems simple enough, however, I do not need or want it to work with a motion sensor. I suppose the easiest way you could help me is to either point me to a tutorial or tell me how to modify that tutorial to my own needs.

• Gerben: we need them to start fogging on command; Where do the commands come from. A human pressing a button? A PC running some software? DMX controller? Smartphone? Without some additional info, we can't add anything that isn't already in the instructable you mentioned.
• Tommy Yamakaitis: @Gerben Well, it would be nice if I could do it from a smartphone.
• Gerben: So basically you don't know yet. How then, are we supposed to be able to help you?
• Tommy Yamakaitis: @Gerben I need help figuring out the best option. I need it as simple and easy as possible so that when the fog is necessary it is sent out, and when we need it to stop it stops.
• Gerben: What determines if it is necessary or not? Easiest solution is to just press the on/off button on the fog machine. You give us no information, but expect us to provide you the golden solution.

Answer 1

Perhaps use a small wireless board like the NRF24L01 (available for around 1ドル each on eBay). Have one at the fogging machine, similar to the Instructable, but instead of a sensor, you turn the machine on and off when a command arrives. For example, send "0" to turn it off and "1" to turn it on. There are examples with the NRF24L01 library.

NRF24L01 module

Then you have an Arduino in the wings nearby where you press a switch when you need to turn the fogging machine on (this would transmit the signal).

• Majenko: Great modules those. I have some with power amplifier and SMA antenna. I haven't found the maximum range yet, but it's certainly measured in the hundreds of meters.
• Tommy Yamakaitis: @Nick This is wireless also?
• Nick Gammon: Yes, they are wireless transceivers. They communicate using SPI so you would need another Arduino (or similar) to send the command. A small one (like a Mini or Micro) could fit into a small box. The transceiver is pretty small - 30 mm long and 15 mm wide.
• Tommy Yamakaitis: @Nick So, I can use this along with the instructable by simply using this instead of the sensor. And, you're saying I would need two arduinos?
• Nick Gammon: Well not exactly "simply using this" - you would need to change the code to read from the transceiver instead of reading from the sensor. You would need an Arduino at each fog machine, and one to have with you to command the others when to turn the fog on and off.