I happened to have a few automotive airbags saved from a vehicle I took parted out (an old BMW). I had saved them no knowing what I was going to do with them, then we had a large pile of sand delivered to our family cottage and I came up with the idea of detonating them under the sand.
- Don’t attempt this unless you’re confident in what you’re doing
- Keep kids away
- Keep power disconnected and physically separated from the airbag
- Don’t try this at home
- Don’t sue me if you do something stupid
The detonator circuit is very simple; the airbag simply needs a power source to detonate so the circuit isn’t really needed (you can just touch the wires to the battery). But I wanted to be able to have the kids do a countdown and press the fire button so I put this together.
The arm switch is a toggle switch which arms the system. The Fire switch is a momentary push button switch (I used a switch from an arcade machine).
I used a 12V SLA battery; I imagine a standard 9V battery would provide enough current to detonate it; but I didn’t try myself. I used 50′ of speaker wire to connect the firing box to the airbag
Burying the airbag in sand gave a good show; the sand didn’t go too far so it seemed fairly safe.