Simple, small, cheap accelerometer/LED?

November 13, 2007 12:41 PM

I'm looking for a simple, small and cheap way of measuring acceleration. Basically, I want to make a set of LEDs light up if they are accelerated significantly, becoming brighter the faster the acceleration happens.

Searching the web yields only very expensive ($300) three-axis accelerometers that are way too sophisticated for my plans. Is there some simple solution, some widget that produces voltage roughly proportional to acceleration?

posted by Zarkonnen to technology (13 comments total)

Searching for 'accelerometer' on Digikey yields a lot of sub-$25 components like this $12 single-axis thinger
posted by 0xFCAF at 12:46 PM on November 13, 2007

Do you need to measure it in all planes? How small does it need to be?
posted by odinsdream at 12:46 PM on November 13, 2007

I think this is basically like what you're looking for.
posted by aubilenon at 12:50 PM on November 13, 2007 [1 favorite]

odinsdream: Ideally, it should be able to measure acceleration in all 3 planes, but does not need to distinguish direction. As for size, no bigger than 5x5x5 cm, but ideally much smaller.
posted by Zarkonnen at 1:02 PM on November 13, 2007

You could make a mechanical accelerometer depending on how large this thing needs to be. Attach a spring and a damper to a permanent magnet that can pass through a wound coil. When the magnet moves you'll get a current.
posted by backseatpilot at 1:03 PM on November 13, 2007

You could also scavenge one out of a Wii remote - those are only about 30 bucks.
posted by backseatpilot at 1:04 PM on November 13, 2007

Thanks aubilenon, that's pretty much perfect. (Apart from the steep-ish price, but I might be able to find a better offer now I know the magic words "ratiometric analog accelerometer".)
posted by Zarkonnen at 1:07 PM on November 13, 2007

A Slide pot, spring and weight would be pretty cheap if your application could handle something that low tech.
posted by Orb2069 at 2:38 PM on November 13, 2007

Instructions on using accelerometers with arduinos.
posted by sebastienbailard at 3:30 PM on November 13, 2007

Note that the device quoted by aubilenon is just a breakout board... I'm not even sure if it comes with the IC. The IC is only $6 though, and if you only need 1, you can usually just get a free sample from AD. Just wire it up to any SMD-DIP adapter board.
posted by noble_rot at 4:05 PM on November 13, 2007

Also, if you only need 2 axes, the ADXL32x series is only $3.50 an IC.
posted by noble_rot at 4:06 PM on November 13, 2007

Why not buy a WiiMote and hack it up? They run about $40.
posted by SlyBevel at 11:36 AM on November 14, 2007

Ah. Backseatpilot beat me to it. Well, seconded then.
posted by SlyBevel at 11:37 AM on November 14, 2007