While I was cleaning up my shop, I found this kit I had put together when I was playing around with electronic stuff. Basically just a little box with a switch and a couple of led's that blink. Simple thing.
Re-purposed it to use it as a reminder for my compressor on off switch. I have a bad habit of sometimes leaving the compressor plugged in and turned on. If I don't close the main air valve, the leak in my overhead spring loaded compressor hose has a leak that can cause the compressor to go on and off at times.
So I just stuck this to the compressor. When I turn on the compressor, I turn on the lights. It serves as a reminder that I have the compressor turned on...
I think this is the kit I originally used for this.