Saturday, January 10, 2009

Accelerometers - MEMS by Analog Devices

The picture to the left is the ADXL322 double axis accelerometer with analog output lines, a close variant to the triple axis version used within Nintendo's Wii video game console. The PCB on which it is shown mounted is only a break out board and has the necessary capacitors to determine the IC's samples per second rate. These easy to use and easy to solder modules typical cost around $30 USD. However, if your soldering skills are sufficient, you'd be much better off buying the accelerometer alone for as low as $3. With the rapid decline in price on these micro engineered machines, hobbyists and businesses everywhere are taking advantage of the benefits these tiny devices can provide.
These accelerometers, with sampling speeds of over 1000 times per second, can be used to directly measure dynamic acceleration and the static acceleration of gravity which can be mathematically converted to terms such as velocity, position, oritentation, jerk, and G force. With the variety of different calculations that can be performed all from this single chip, it is easy to realize a vast variety of different machines and devices such as digital hourglasses, computer pointing devices, degree of impact sensors, free fall sensors (especially important if you drop your laptop), Star Wars type lightsaber toys, image stablization for binoculars, telescopes, and cameras... the list is endless. A single chip such as this, can provide all of the sensors within a single package for a fully capable self driving car, since extrapolation of even position can be somewhat accurate, but more importantly, speed and impacts can be known, without the need to count wheel rotations and hope the wheels didn't skip, nor wire impact sensors 360 degrees around the chassis. If triple axis is desired, the ADXL330 is a very well known and widely available model to provide just that. Several other versions can provide PWM outputs, instead of analog, for easy integration with a digital microcontroller. So, please go buy some of these devices and build something amazing, and let me know how it turns out.

1 comment:

Scifi Chrome Webmaster said...

very interesting article... love your site... did you post anything yet about the new memory storage devices coming out... they are sopposed to blow the stuff on the market out of the water... basically hard drive sized memory with no moving parts... no heat issues...