Lawn Pest Control

Folks, havent done any programming for ages but understand the idea.

Want to resolve a problem with a neighbour’s dog on my front lawn and I’m thinking a PIR sensor connected to an arduino then activating a water pipe solenoid which works a sprinkler for a few seconds.

The water solenoid is 12v but can be activated by 6-12v

Will the arduino have to go through a relay to work the solenoid or might it activate this directly.

Any suggestions appreciated.


Geffers, the Arduino can only supply 5 volts at around 20mA max from any pin so yes, you will definitely have to boost the ability with either a MOSFET or small relay - either solution will need to be able to cope with whatever current the water solenoid will draw - plus some safety overhead (for “Bullet-proofing”).

If you go for a MOSFET you may also need to incorporate a back-EMF diode across the solenoid as the solenoid will be a big inductor.

The likes of EBAY can find you an “arduino relay module” as a ready-made solution.

I was just thinking about a project along these lines today- except I would have to mount it on my roof to combat really loud stompy birds that skitter around the flat parts from about 4-5AM. Seriously, it sounds like there’s a family of tiny people up there moving around furniture.

But: non-electrical question: what kind of dog? If it’s a labrador retriever like our pets, they will be drawn to your sprinkler. :-)

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Retriever, the owner of the garden has a Labrador herself but ends up clearing up for her own dog and the neighbour’s.

Get on with the neighbours fine, told them about it, sometimes they clear up but many times not.

So, rather than cause an issue want to try the sprinkler, if that don’t work maybe a cannon (only joking).