WaterValveShield controls your garden spigot

Arduino Energy & Sustainability
WaterValveShield controls your garden spigot
watershield.JPG

First Ray built a minty water valve controller that gave him control over a garden water supply, then he turned it into a shield.

For the water valve, I picked the Orbit yard watering valve. It’s widely available in home improvement stores, and it is cheap. It has two pins: applying +24v opens the valve, and -24v closes the valve. It uses a latch solenoid, drawing power only when you open or close it. This makes it very power efficient.

To use a single li-poly battery to drive the valve, I needed a voltage booster to raise the 3.6v provided by the battery to 24v momentarily before connecting to the valve solenoid. For this I chose an LT1303 DC/DC step-up converter, but any similar converter will do as well. Switching between applying +24v or -24v to the solenoid is achieved by using some MOSFETs. I can’t use small BJT transistors because they won’t handle the large impulse current through the solenoid (as high as 5A). Darlington transistor would work but I prefer MOSFETS for their power efficiency.

Read the first link to get a sense of the overall project; at any rate, Ray supplies schematics and code for both.

Discuss this article with the rest of the community on our Discord server!
Tagged

My interests include writing, electronics, RPGs, scifi, hackers & hackerspaces, 3D printing, building sets & toys. @johnbaichtal nerdage.net

View more articles by John Baichtal

ADVERTISEMENT

FEEDBACK