Pinch Valve

by annina in Circuits > Robots

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Pinch Valve

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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.

The Parts

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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.)

Assembling the Parts

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

Assembling the Parts

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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.

Open Valve

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

The Valve in the Context of a Larger Project

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