Outdoor Adventure USA

Many of you guys have seen my massive, crooked shooting, 3 gal antenna launching air cannon.
It's been fun, but it's time for an upgrade.

I've built a newer version all out pf PVC that sits on the shoulder like a bazooka, But it has much less air capacity than the last model. On the original version, the time the air valve was open, was directly proportional to the time the trigger button was held down which can waste a lot of air from both mis-shooting with not enough air/trigger time and also wasting air with too much trigger time. In an effort to save air, I've decided to make a timed trigger for consistent air saving launches... but it hasn't come without minor challenges..

I've built a one-shot multivibrator (555 Timer) to time the trigger. which is great for forcing short trigger times to keep the valve open for 200ms. You can see here that a 124ms trigger time results in a 200ms valve open time. However if you hold the trigger, the valve closes for a very small amount of time before opening right back up. I'm trying to think of various, simple, ways to keep the trigger from being able to retrigger the valve within a certain about of time. Any ideas are welcome.

well... after some research, I've figured it out...

adding a capacitor to the input causes a brief drop in voltage.. just enough to trigger the timer..
The cap in this diagram is the cap on the input.. which stays low while I hold the trigger button down.
now time to add just a few more components to handle the current from driving the solenoid on the valve.. solder it together... and then... Helloooo CQ..

Steeevo

I kinda like to old tennis ball thrower. It wasn't perfectly accurate, but it was sure fun to shoot!

Oh yes------good luck explaining to the cops what that bazooka looking device is for!

should I have posted this in the firearms section? lol

This should be much more accurate than the old one so we can get on the air faster!