Simple proximity sensor

[Dustin Andrews] built this add-on board which works as a proximity sensor. He wanted a standalone sensor for his Arduino projects which would use a single pin as a trigger. This lets him alert the Arduino when an object approaches the sensor without the need for polling or extra code on the Arduino side of things.

As you can see, a single chip on the board takes care of all the work. That’s an ATtiny13, they’re inexpensive and sometimes you can even salvage them from consumer electronics like this color changing light bulb. The microcontroller monitors the phototransistor which is wrapped in electrical tape to isolate it from the IR LED emitters on either side. This setup creates a reflective sensor. When an object nears the board, the infrared light from the emitters reflects off of it and onto the phototransistor. And since the Arduino works as an AVR programmer you don’t need special hardware to program the device.

808 camera hack produces a time-lapse Tic Tac box

It’s not really conceived as a spy cam, but it could be. [Quinn Dunki] built this tiny time-lapse camera project with racing in mind. She’s involved in a group that endurance races clunkers, and part of the fun is sharing the experience of riding around in the old beaters. The module seen above takes a picture every four seconds and will last 24 hours before needing new batteries or an SD card change. We wonder if that’s longer than some of the ‘racecars’ make it?

She picked up an 808 camera, which looks like the key fob you use to unlock your car doors. They’re so cheap you can include them in projects and not really care if you don’t get them back. Inside it’s got a small lithium battery, the circuit board with a processor, microSD card slot, and of course the SSD used to capture the images. To control the device she used a tiny relay with an ATtiny13 used for the timing. We think the battery selection is a bit overboard, but maybe the next version will be a little more conservative.

There was one folly along the way. She wanted to attach this to the body of the car with a handful of magnets. But they don’t play nicely with the magnetic relays so that was out. The solution was to add that lanyard ring to the case which will allow the camera to be zip tied to the vehicle. So far there are no time-lapse movies available, but keep your eyes on our links posts and we’ll try to include one when it pops up.