Antenna Cannon 2.0

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SteeevO
Posts: 236
Joined: Sat Mar 22, 2008 1:17 am
Call Sign: KF6WVM

Antenna Cannon 2.0

#1

Post by SteeevO » Mon Aug 14, 2017 9:10 pm

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.
IMAG2690.jpg
Cannon 2.0
IMAG2690.jpg (2.15 MiB) Viewed 170 times
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.
TEK00003.PNG
Single Shot - Good
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However if you hold the trigger, the valve closes for a very small amount of time before opening right back up.
TEK00004.PNG
Multi Shot - Bad
TEK00004.PNG (8.99 KiB) Viewed 170 times
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.

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SteeevO
Posts: 236
Joined: Sat Mar 22, 2008 1:17 am
Call Sign: KF6WVM

Re: Antenna Cannon 2.0

#2

Post by SteeevO » Wed Aug 16, 2017 12:55 am

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.
TEK00005.PNG
TEK00005.PNG (6.24 KiB) Viewed 153 times

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..

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DaveK
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Re: Antenna Cannon 2.0

#3

Post by DaveK » Fri Aug 18, 2017 9:12 pm

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!
DaveK
K6DTK


Extremism in the defense of liberty is no vice.
Moderation in the pursuit of justice is no virtue.

User avatar
SteeevO
Posts: 236
Joined: Sat Mar 22, 2008 1:17 am
Call Sign: KF6WVM

Re: Antenna Cannon 2.0

#4

Post by SteeevO » Fri Aug 25, 2017 12:04 am

should I have posted this in the firearms section? :shock: lol

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

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