Banging things with a bicycle pump

I have been messing around with a trigger that pumps air into a bicycle pump, which bangs under a surface loaded with objects, making them jump. The trigger fires the camera with precise timing, so you can for example shoot some shiny things flying:

I call this one "Space Walk":

The basic technique is to bang on the underside of a thin material (a flexible floor tile, clamped to a Workmate), so that the objects sitting on the surface jump up in the air. As compared with dropping objects, this method makes them stay somewhat aligned in formation flight. Like so:

That shot started with the blocks all lined up:

You can see some clamps at the right side. Bang on the underside of the tile and it flexes up on the left, throwing the blocks in the air.

The trick is in controlling the timing relationships, and for that I use a Pluto Trigger. I bought it with the Pluto Valve accessory, which lets you release up to three water drops at precise times, and take a photo at another precise time. The valve is solenoid-driven, and it has an isolated MOSFET driver board. Hmmm, I thought... I wonder what else I could trigger that way.

So I bought an isolated MOSFET driver board from Amazon. It's a four channel board but I'm only using one channel. I also bought a 12-Volt solenoid valve with 1/4" NPT threaded inlet and outlet, and wired it all up. Connected to a compressor, set to about 80 PSI, I can make it puff out bursts of air and blow stuff around. I could make sort-of little explosions that way, but I haven't tried photographing those yet.

I figured a piston / pneumatic actuator would be something fun to try, and it struck me that a bicycle pump is basically a piston that can work with 80 PSI easily. A slight wrinkle is that the pump uses one-way valves, so you have to plug the main hose and inject compressed air into the pump's intake port. That turned out to be pretty easy with the old pump I had lying around.

Now the Pluto Trigger can inject timed bursts of air into the pump, making the handle extend. I was pleasantly surprised at the vigor with which the thing extends. A 30-millisecond pulse pushes the handle out 6" or so almost instantly. In the photos here I am driving the pump for 30ms and firing the camera at the 31ms mark. The tile gets whacked probably around 25ms into the air pulse.

Between shots I push down the pump handle to reset it for the next shot. That works because my plumbing includes a safety coupling, which has a tiny hole to let some air escape. If I forget to push the handle down, it goes up another several inches, resulting in botched shots like this one:

I've got a bunch more things I'd like to try with my compressor set-up, maybe in combination with the Pluto Valve. I might be able to toss things in the air and drop water on them, or drop water then hit it with air or a projectile. Should be fun. More on that later.