Thursday, March 11, 2010

Introducing the Dual-Axis Gyro Module

The Dual-Axis Gyro is the latest project from the joint engineering effort between Liquidware and Modern Device.

I was looking through some of the nautical navigation books I picked up when I did a little research for the Compass Sensor a couple weeks ago. When compasses were inaccurate or unavailable, seafarers would turn to gyroscopes as a “keeper of direction”, the same way a pendulum in a clock was a “keeper of time”.

I had always been under the impression that the gyroscope was all about balance, and that it was more or less a kid’s toy (they are actually pretty fun to play with) Something similar to a popular corporate desk toy…or one of those plastic grip spinners that tennis players use…

The aspect about keeping balance is true, but in tilting to keep balance, the gyroscope also measures angular acceleration and helps keep track of an object’s orientation, independent of any other landmarks or determinants of direction.

File:Foucault's gyroscope.jpg

Luckily, I don’t have to strap one of these contraptions to the UAV I’m building, and the dual-axis gyro Paul and I came up with is pretty mobile.


The board uses an InvenSense IDG-500 MEMS chip that provides 500°/sec full scale range and 2mV/°/sec sensitivity of rotation. The chip also reads out temperature as well, and has an Auto Zero feature to reduce bias drift. Since it’s a 3V chip, the board itself has 5V tolerance protection for all those overvoltages I’ve ever had.

The hollow center makes the board axis mountable, and I’m thinking of using some jumper cables to hook it back up to an Arduino or mini protoboard. Here’s a snapshot of what I’m playing with at the moment:

I’m thinking about maybe putting it on the axis of a turntable? Or something else that spins and wobbles? I’ll post it as soon as I figure it out, and upload some “up and running code” as well.

In the meantime, I’ve built and tested the first batch, and they’re online over at Modern Device :)

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