A year ago [Lochie] bought an Airwick automatic air freshener, and while he thought it was a cool gadget, the freshening spray and the novelty ran out in short order. The device collected dust in his room for some a while until he recently unearthed it, and noticed that a perfectly good PIR sensor was looking him in the face all this time.

He disassembled the air freshener, then set out to figure out how he could interface with the PIR sensor. After finding a helpful Instructable on the topic, he had full access to the sensor’s signals, allowing him to easily wire it up to an Arduino. He decided it would be fun to trigger some simple music any time someone entered his room, so he encoded a short bit of the Super Mario Brothers theme in RTTTL, as he explains in the video below.

It’s a simple little hack, but [Lochie] is pleased with it, and we imagine that he likely has a long list of other creative ideas in mind for his newly discovered PIR sensor.

Airwick air fresheners come with an amazing feature. They spray air freshener every once in a while no matter what. It is extremely wasteful and obviously a marketing plan to force you to buy more. There is a solution though. You can hack them, to turn them back in to a manual release like they used to be.  Two cuts and two soldered wires is all that is necessary.

yes, we know you could just buy an aerosol, but many of us just come home and find them in our bathrooms since someone else in the house bought it. If you’ve already got it, why not hack it? This is also a great project for teaching beginners how to improve hardware.

[thanks Asmor]