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IMUs for Lego NXT

Posted: Wed Aug 27, 2014 11:42 am
by EpicentrE
Hi all,

I'm looking for a sensor which includes an accelerometer and gyro for use in a Lego Mindstorms NXT project. I've found two possible candidates:

http://www.dexterindustries.com/manual/ ... mu-sensor/
http://www.mindsensors.com/index.php?mo ... AGE_id=158 (more info at http://www.mindsensors.com/index.php?mo ... le_id=1369)

But I'm getting a little bit confused when trying to compare the two due to them using different terminology to specify their accuracy and resolutions. All I basically want to know is which one has the highest resolution and therefore the smallest "steps". I'm attempting to make a balancing unicycle-type robot, and so the more accurate the better. Could someone who's more experienced with this kind of thing please take a look and let me know your opinion on which of these sensors would be best suited to the task?

Many thanks.

Re: IMUs for Lego NXT

Posted: Wed Aug 27, 2014 2:46 pm
by BeligerAnt
From a quick glance it looks as if the gyroscope is very similar (if not the same) on the two boards. There may be a slight difference between the accelerometers but they look very similar.
The MindSensors device seems to include some extras like a compass and a derived tilt measurement (take accelerometer readings and do some trig').

I think in practice either of these should be good enough.

Choose the MindSensors device if you want to extend/change the project to include navigation at some point. The Dexter data includes links to the actual accelerometer and gyroscope datasheets if you need that sort of detail. MindSensors don't even say what sensors they use.

Good luck with it. I played with scratch-buiding one once using an Arduino and sensors from a Wii Motion+ but could never figure out whether I actually had enough speed to be able to balance, let alone get the system stable. If you have a platform that you know is at least capable of balancing you have taken out one of the biggest unknowns - then it's just software!

Re: IMUs for Lego NXT

Posted: Thu Aug 28, 2014 11:35 am
by EpicentrE
Thanks very much for the help Gary. If I ever get anything working I'll post it here ;).