Wiimote car accelerometer

This one’s pretty simple, but anyone who’s ever spent time tweaking an engine will appreciate it. [Kevin]’s been using a wiimote to measure the acceleration of his car. He put together a script to dump the accelerometer output to a CSV file, then graphed it with Excel. He notes that the accelerometer output isn’t that precise, but it’s good enough to give you feedback on your mods.

19 thoughts on “Wiimote car accelerometer

  1. I wish I could download the information from the accelerometers built into my car stereo. I can measure HP and gravity forces (both accel/decel and turning) and it shows that on the screen, but it would be fun to actually see a graph of all of the data.

  2. So, if you have start location, acceleration, braking and turning data, couldn’t you take that information and apply it to a map. Some Google maps api action could map your trip or give you your current location.

  3. I’ve been waiting for this. This is cool!

    @6: This is way too inaccurate to do that, but if you got really, really accurate accelerometers, then yes, that would work for short distances.

  4. @sp`ange: in theory, yes. in application, the ADXL330’s used in Wiimotes just isn’t that great. they are great for measuring general acceleration, but not precise enough to figure out position acceptably. the amount of error you get would be tremendous for trying to figure out position and such. multiple accelerometers in different locations working to get an “average” position or something would work much better.

    course, you could try with just one wiimote and prove me wrong; I bet the error would make figuring out position and such very difficult.

  5. #6, in theory, yeah. But you have a lot of noise in that kind of data, and MEMs systems (like the accelerometer and gyros) tend to experience null drift – the ‘at rest’ level moves around (slowly). Null drift isn’t a problem on short time spans because the null level is approximately constant over short times, but over minutes or hours, you need a reference to re-zero your signal; that’s what the Wii light bar does. If you integrated all the data/errors to try to get a map of distance, I suspect you would end up with nothing but garbage.

  6. Gah, I’ve been working on this very same idea but done properly. The wiimote is accurate enough to tally up with my gps so I’m assuming that there is just some cumulative error with his ‘high school physics’

  7. wouldn’t be too hard to position several wiimotes in the car to get more accurate readings. pitch, yaw, roll, etc… it would also require a better means of of securing the device to the car.

    I’m only using the “G” values, which I presume are already post-processed. Someone else can use the rawaccel_ values for more accurate readings. The G values were just more convenient.

  8. The lame thing about this is that there are several other simpler, pure accelerometer chip devices you can already hook up to a computer to do this. This is a pretty bad way to go about taking these measurements, especially since using precision accelerometers is already cheap and easy. But good aplication of the Wii-mote none the less…

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