Introduction: Pinch Valve

This is a simple way to control the flow of water via a microcontroller or similar. Most commercial irrigation valves require a certain amount of water pressure. This valve is designed for low water pressure. It is used in the eRiceCooker project, a fully automated system that cooks rice according to the frequency of news reports about genetically modified rice.

Step 1: The Parts

You will need:
- A servo motor
- Enough flexible latex tubing, outside diameter 3/8" (medical supply store)
- Metal pipe outside diameter 1/2" (home depot)
- Four zip ties (they can be a bit wider than the ones pictured)
- two tiny screws & bolts
- Flat material which can be cut, sanded and drilled (plexiglass, wood, aluminum, etc.)

Step 2: Assembling the Parts

This is how the fully assembled valve looks from the front.

Step 3: Assembling the Parts

This is how the assembled valve looks from the back.

Assembling the valve is really very simple:
- Cut the metal pipe in two even-sized pieces.
- Cut the plexi (or other material), so it forms an oval.
- Drill some holes in it, and attach it to one of the servo motor's arms using the screws.
- Push the latex tubing through the pipe-parts
- Attach the pipe-parts to the plexi.

Step 4: Open Valve

This is how it looks when the valve is open and the water flows.

Step 5: The Valve in the Context of a Larger Project

Once you've assembled and tested the valve, you can add some water.


maker12 (author)2007-12-14

I HATE MICRO,S (all haill nash for non micro based ic,s)

VelvetElvis (author)2006-11-10

Nice photos! I wish all Instructables were this clear.

cheesy (author)2006-11-08

Any suggestions on where to get cheap servos? Also, tips on hooking them up to microcontrollers?

bluelip (author)cheesy2006-11-08

Check your local RC/Hobby store. I picked up two Futaba S3004 servos last week for $13 each. I thought it was a good deal since the last time I bought a servo, a few years ago, they were over over 20 bucks each.

trebuchet03 (author)2006-11-06

oooo -I like that microcontroller setup (except it requires a programmer for initial setup :P) That site is acting a bit flaky (not sure if it's my end to blame) - I've been wanting to get into microcontrollers and I think this is how I'm going to do it (fits the budget :P).

Myself (author)trebuchet032006-11-07

Allow me to plug the Serial Wombat here. I picked one up a few months ago at Hamvention and it's pretty sweet: A programmed PIC that can act independently, but is mostly an I/O peripheral for your PC. It's incredibly easy to do tasks like drive steppers and servos, read encoders and pots, and control LCDs.

rimar2000 (author)2006-11-07


Crash2108 (author)2006-11-06

I was going to make an automated risotto maker.

LasVegas (author)2006-11-06

Love the automated rice cooker. Now can you make an automated potato masher? Or, better yet! an automated port roaster for every time a federal bill is passed.

ARVash (author)2006-11-06

Rofl XD. i like it :3

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