Keeping live plants in an aquarium happy can be quite a chore. One of the frequent rituals is adding fertilizer, which is called dosing. [Majstor76] came up with a creative way to automatically dose using an air freshener. He got rid of the canister that holds the scent and re-purposed a hand soap pump to move the nutrient-rich liquid. After the break you can see that there’s no shortage of power to actuate the pump and the powered air freshener base has a delay circuit, allowing for a few different time-release options. As long as the volumetric output is fairly consistent we figure you can dilute your fertilizer to fine-tune the dose.

[Thanks Chris]

Now you can capture pictures of our furry friends by building a motion activated wildlife camera. [Doug Paradis] took his Air Freshener hack and used it to trigger a camera. The white dome in the picture above is the PIR sensor from an Air Wick Freshmatic, along with a cheap keychain camera and an MSP430 microcontroller. He used one of the chips that came with the TI Launchpad, a transistor, and some discreet components to interface the devices and then put them into a project box. Now he’s got a fully configurable motion-sensing camera.

[Doug Paradis] took a good look inside the Air Wick Freshmatic Compact i-Motion and then stole all the parts for other projects. We’ve looked at adding a manual spray button or making air fresheners Internet enabled before. Those models didn’t have parts that were all that interesting, but this one has a passive infrared motion sensor. You’ll also gain three switches, a PNP transistor, and an LED.

Price seems to be all over the map for this model, but [Doug] says you can find it for $8 or less. After showing how to make a tool to bypass the triangular security screws, he explains how to access the PIR sensor. But if you want to be all you can be with the hardware, he details the modifications needed to patch into the analog and digital circuitry on the rest of the board too.

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]