Make a motor move a PVC pipe back and forth within another pipe

Hello all!

I was wondering if any of you know how to make an attachment to a motor wheel that will, in turn, slide a piece of PVC tube within another piece of PVC. I'm not the best at expaining, but I'm essentially making a connection between two pipes (that are seated within a bigger diameter pipe) by making a motor move. So as the motor goes, one of the pipes retracts back at least 4 inches and then closes again to meet the other pipe. I have looked online, but I can't seem to figure out what the hell I'm supposed to do. Any help?

Also, I'm making an automatic water balloon launcher, so that's what this is needed for. Think of the mechanism I'm making like a Nerf shotgun or such, where when you pump it, it loads in a shell, (water balloon), and when you pump it back, it locks the shell in place. Except the pump is an automatic motor.

Help. :o

Hi!

For Your pipe moving project look for linear actuators. I have seen such on the eBay . Some use stepper motor, some use servo.

The only problem with that is that I need it to automatically go back and forth. Is there a way to do that with an arduino?

Absolutly! I run an Arduino UNO with a stepper motor shield in order to control a CNC machine. The test program is small, runs the stepper forwards and backwards any amount I want.

Get a wheel that's 2" radius, attach a linkage, so every rotation is a 4" linear motion.

INTP:
Get a wheel that's 2" radius, attach a linkage, so every rotation is a 4" linear motion.

That radius would be measured along a 3D curve? Because flat, the turn would be 4 * Pi inches.

GoForSmoke:
That radius would be measured along a 3D curve? Because flat, the turn would be 4 * Pi inches.

He just wants linear motion. The pipe would move back and forth along one vector just 4". No pi involved.

physiks2017:
The only problem with that is that I need it to automatically go back and forth. Is there a way to do that with an arduino?

Perhaps something pneumatic, you can get solenoid valves and only need a source of pressure equal to the job. Get a nitrogen tank with regulator if you need muscle, or a paint sprayer setup for light work.

INTP:
He just wants linear motion. The pipe would move back and forth along one vector just 4". No pi involved.

I was thinking rollers, but those don't limit.

Thank you so much INTP! That's exactly what I needed.

Where would I find those linkages?

physiks2017:
Where would I find those linkages?

You MAKE them. Part of the fun!

Paul

If you're not comfortable fabricating stuff like this from scratch there are places like Servo City which can provide the basic parts - Erector Set sort of material.

The punch press I used to run used a cam to drive the punch like a 25 ton bullet. There was a flywheel with a clutch to drive the cam.

If you use an electric motor it will have to be strong enough to move the pipe from static stop. I am sure there are capable motors, get one that is max rated at least 50% stronger than required.

Hardware store, some bolts perhaps with eye hooks, nylon bushings, a couple flat steel reinforcement bars, be creative.