# Vibration sensor (accelerometer?)

For growing crystals it is important that there are no vibrations. Is there a cheap and easy way to measure vibrations in the floor, like people walking, doors closing etc.?

Perhaps an accelerometer is possible, but those are pretty expensive (Nun chuck is less expensive).

• Would gutting a Wii nun chuck and using that be too expensive? The major issue may be that it isn't sensitive enough. – W5VO Apr 12 '10 at 15:49
• You can get accelerometers for less than 10 dollars that are quite nice. – Kortuk Apr 21 '10 at 10:58
• @Kortuk You might want to say where? – Lars Apr 21 '10 at 21:13
• Hey, @Lars what did you end up using? I'm working on a very similar project and would love to know – tr33hous Jun 24 '15 at 12:58

You can use a cheap piezo sounder to detect vibration.

http://www.arduino.cc/en/Tutorial/KnockSensor

• Thanks, I will try this. If it does not work, I will try purpose-built piezoelectric (Tim's post). – Lars Apr 13 '10 at 13:56

Purpose-built piezo vibration sensors (e.g. this one) are cheap and fairly sensitive.

The iMEMs sensors from Analog Devices and/or ST are available for < $10 from Digi-Key. Depending on the package you pick, you can get all three axes digitized and output on a SPI bus. A microphone might work. Cover it in hot glue and stick it to the object you're monitoring. That will keep out air vibrations (to a degree) and couple it to the conducted vibrations. Well, it SHOULD anyway! How about a cheap dev kit that has a accelerometer? There is a couple of them to choose from but maybe the STM32 Primer, and digikey used to sell those for approx 48$. It was deprecated in favor of the STM32 Primer 2 for which the plugin board is less expensive but the base kit is significantly more expensive.

A extra little feature is that this is a usb-based dev kit, so you can send the data to a computer and create a "data-logger".

iPhone? Similar to @W5VO's suggestion for a Wii.

• Why the down vote? – Brian Carlton Feb 15 '11 at 15:59
• I agree with Brian. This is not a stupid idea, especially if you are trying to do it on the cheap as stated. It is entirely possible that there is a surplus older smartphone going begging. – Peter Wone Jul 22 '13 at 6:46

There is an app for setting up record decks. Shows the vibrations on the display

Mulit Siesmometer. looks good with an alarm but ihave never used it.