First-time poster and Arduino newbie. Looking for some guidance on a project I'm looking to kick off. I want to build a motion-sensing sprinkler to keep my dog cool in summer. Basically, looking to build something that he can stand under to activate a water flow which switches off when he moves away... likely using a garden sprinkler mounted upside down, a solenoid valve and an Arduino-driven motion sensor.
Wondering if anybody has done any similar garden/irrigation projects and could offer some advice on the hardware required and/or lessons learned
"Standing under" is exactly the opposite of motion so you probably want something to check his presence, not motion.
An ultrasonic sensor like an hc-sr04 should do the trick, and has a range long enough for you to position it out of the spray. Easy to program, there's a library called NewPing().
And there are solenoid valves like this that can be controlled with an Arduino through a transistor. (edit: make sure the one you get can handle mains pressure.)
Indeed, something weight based may work better, assuming the dog is big enough to be reliably detected, while the layer of water that forms during the shower (plus the pressure of water drops falling down) do not set it off.
Ultrasound sensors will likely detect the water as well, so timer based approach (2 mins on, then at least 5 or 10 seconds off to allow for the shower to stop dripping and triggering the next 2 mins).