Let's Make Robots!

Razor IMU - 9 Degrees of Freedom - Has anyone used it?

Hello People

I wonder if anyone has any experiance with the Razor IMU with 9 Degrees of Freedom from sparkfun. Is is value for money?

I have found one here http://proto-pic.co.uk/9-degrees-of-freedom-razor-imu-ahrs-compatible/ at what seems a very reasonable price as far as UK prices are concerned (£72 + 6 shipping). Some places are mad expensive, up to almost £120...

Anyway, still in the vein of attempting to give my bot some more brains than simply non-collision movement I am looking at gyros, accelerometers and magnometers. Hoping to figure out a fairly accurate method of DR.

Does it make sence buying something like this with the 3 different components on one board + a dedicated AVR 328 processor or would I be better off buying the components seperately? Arguments either way would be appreciated.


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I think in part it depends on how much time and experience you have.  If you don't have experience with accelerometers & gyroscopes, surface mount soldering, PCB layout and circuit design, expect to be at it for awhile, to learn a lot, and to save possibly nothing depending on your costs: boards/components/shipping/possible equipment and defects from learning.

I can only assume you are talking about dead-reckoning, but it always helps to spell it out.

Hi rogue

I was more talking about buying seperate modules already on seperate breakout boards as opposed to buying the components and doing all the soldering myself.

I have done that for an arduino clone and also a motor controller, but for the 10-15 pounds I saved I took a good 10-15 hours to do it... design, solder, test etc. learning experiance but at a rate of £1 per hour it certainly was not worth it in a strictly financial sense.


Hmm... in the end I have decided to go for a magnometer/accelerometer combo for £22 over here http://www.hobbytronics.co.uk/lsm303dlh-tilt-compass?keyword=compass

I decided that saves £40 for right now. Maybe when I am ready for the gyroscope I will buy a gyroscope breakout or the 9 DOF if I really need it.

So my DR for now will consist of angle turned + time traveled at pre-measured speed... simple but my research into DR using INS indicates this is not a trivial subject.

There is an open source project where they are looking into INS navigation - specifically for flying vehicles... http://www.openpilot.org/products/openpilot-coptercontrol-platform/ which I will be watching. Seems the INS maths is *really* hard.



I see, you might then consider pololu's miniIMU-9, which doesn't have a brain but is less than half the price of a typical "smart" IMU