Pi-Rex: a bark-activated door opener for dogs

Here’s a weekend project from Dave Hunt for dog owners whose best friends can’t work out whether they want to be inside or outside.

Dave came up with Pi-Rex when the sleep deprivation caused by his new dog barking to be let in or out alternately became too much to bear. She tends to do it at the same time every morning. Dave says: “I could do this with a timer switch and a door strike, but where’s the fun in that?” Indeed, Dave. So instead, he’s made a door that responds to barking. Barking.

You absolutely have to watch the video. I’m not sure whether I enjoyed Dave’s dog impression or his reaction to the door opening the most, but the combined effect had me snorting coffee.

A noise detection circuit tuned to respond to loud dog sounds fires a motor which unlocks the door, and a weight (actually a large bird feeder) and pulley system swings the unlocked door open. Dave says: “I picked up the audio detection circuit in Maplin as a DIY kit for €9.99, the kind of ones where you get all the components and a PCB in a bag, and solder them all together. It took about 30 minutes, but worked perfectly; I could bark, and the LEDs would light as I barked. My family thought I was gone mad when they heard me making dog noises in my workshop.”

Dave, this is magnificent work.

If you want to set up Dave’s dog-operated system in your own house, head over to his website, where all the code you’ll need, some wiring instructions and a parts list are available. He suggests you might like to sample the audio collected and make the door respond to…known barks. I do have one question, Dave: have you trained the dog to shut the door behind herself yet?