[monkeysinacan] wanted to add a fog machine to his Halloween display, but he says that the cheaper consumer-grade models are pretty unruly beasts. He cites short duty cycles and tricky fog control as his two biggest gripes with these sorts of foggers. He decided make the fogging process a little more manageable, and modified his to only generate fog when someone was walking nearby.

One obvious concern with this sort of setup is the warm-up time required to get the device ready to produce fog. If it were to only turn on when someone walked by, [monkeysinacan] would miss his mark each and every time. To ensure that his machine was accurate, he rigged it so that the heat exchanger stayed powered on, triggering the fog juice pump as needed.

To do this, he used an ultrasonic sensor similar to, but cheaper than a Parallax Ping unit. Paired with an Arduino, the sensor triggers the fog machine’s pump for 20 seconds whenever anyone gets within 6 feet of it.

While he hasn’t posted video of the modified fogger at work, it sounds like a solid plan to us.

Filed under: arduino hacks, Holiday Hacks

In an effort to improve his marital standing [Tech B] hacked an air freshener to make it Internet controllable. The main component here is a Glade Sense and Spray. It cost him $7 and is meant to spray out some sweet smells when it senses motion in the room. The unit also has a manual spray button which he patched into with the help of a relay. From there some Arduino code and an IRC bot take over, letting him unleash freshness from anywhere he has IRC access.

When reading about this we were also thinking: “motion sensing circuitry available at local stores for just $7?”. We may have to conduct an investigation into the alternative usefulness of that package.

If you have another brand of automatic freshener around it should be just as easy to hack as this one was.

Sometimes, pets need to be trained to stay away from certain things. Over at sump.org, his cats needed to be kept out of his room. He used their natural fear of water by creating the waterwall, a motion-sensing device that sprays water. The project is incredibly simple and uses very few components. It is based around an IR intrusion detector and a windshield washer pump. Although that worked well enough, he also hooked it up to his computer via the parallel port so that he could take pictures as the cats (or people) are sprayed. Although the project is old, it shows how few components are really needed to achieve this kind of behavior.

Related: Motion detecting cat toy

[thanks todd]

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