One small page on theory and the rest on how to blink an LED… not very informative.

@Jeff

YES!!!

Urgh…. utterly useless.

To further Jeff’s comment if you buy a nunchuck but it online and also get a breakoutboard so you can keep it all together(resell + the connections are a bitch to solder). The nunchuck its self is an I2C device so you can interface it and get it’s 3-axis accelerometer info. dual axis analog stick and 2 buttons… wow it’s a sad day when half a paragraph is more useful than a HAD post.

Check out ebay/amazon they can be had for £5 (third party versions) and you get a decent amount hacker fodder.

8 pages on how to flash an LED? If that isn’t bad enough, where is the printable version of the article?

Adding to Alexander’s comment:
if more accurate motion data is desired, try getting a Wii MotionPlus in addition to the nunchuk. The MotionPlus has a really nice gyro which can help supplement the readings from the nunchuck

I would suggest you NOT buy a third party nunchuck/wmp; the original Nintendo nunchuck/wmp is the only one that works with all the code already available online.

What I did was import the adc output into my program, then I’d store those in an array of 5 to 10 in length, I could play with the number to fine tune it, once it was full, I would start averaging the input, with the average of the array values, then take out the oldest, and put in the new average, so it would then fill up with averaged values. Depending on how fast I sampled, along with how big the array was, I got it down to some decent stability, but it was always at the cost of speed, or accuracy, in regards to sample rate, making it skip across the screen. I don’t know if the 3 axis accelerometers all will spit out some wildly varying out put, or what, it just seemed like every few samples, it would say go from around .70 to .75 volts, to like .85 or something then back down, even tho it wasn’t moved. I got it smooth enough for my investigation and play with it, but as far as a controller, like I saw someone had made one to control a video game, it just seemed a bit unpredictable. Maybe a higher quality accelerometer would be better? I didn’t exactly buy something high end or anything I think, or maybe some filters on it before going to the microcontroller. I think it would work fine if you were just datalogging, but for a wii like interface, it seemed lacking.

Gosh, Folks… Constructive criticism can lead to much better results sometimes.

Frankly, while this is very elementary, I found it rather nice to see something here for any beginning hackers and/or hackers who focus more on a catagory here labeled “Misc. Hacks,” like the non-electronic and non-IC/processor-related ones.

If HaD stuck enirely to electronics, programming and “high-end hacks,” very few beginners would ever stick around to be able to learn from all you apparently overly educated hackers!

Thanks, HaD! I’ll be cutting & pasting into a printable document and using this info for some students to work on problem solving and taking it futher. Saves me the time of writing it all myself.

Yes this would be why it says “beginner concepts”

.. read the title, don’t like it, don’t read the article.

@PhilKll, that’s a moving average

@PhilKll low pass filter works, see the datasheet…

On a side note, accelerometers can probably be used (with a little creative voodoo involving supercooling via peltiers and tilt compensation) to detect high frequency gravitational waves.
the effect is real and highly controversial as it suggests that gravitational waves not only exist but can cause real effects many light years from the source.

generating HFGWs can be done using a superconducting disk and a high voltage source, it seems that somehow the sudden microquenches propagate HFGWs at right angles to the source, see ning li’s work…

that said unless you are looking for them you would never know they were there, as the effect is miniscule. Certainly not enough to knock planes out of the sky or anything Half Lifey.

:)

Reggie: good point about the ADC reference voltage, it should be noted that if the accelerometer has a built-in regulator like the nice ones from http://www.dimensionengineering.com then your microcontroller should also be run from a fixed regulated voltage, or you’ll start getting wrong readings if the micocontroller is being powered directly from batteries as the batteries voltage slowly drops.

@DB
yes that’s correct in theory but the problem with the integrator is that you will integrate the offset of the sensor too (which drifts over time due to temperature and other effects and thus cannot be compensated reliably (and even when it’s known you still cant compensate it perfectly))
This gives you a constant growing error in velocity and a quadratic growing error in position. (because integrate(integrate(offset, t), t) = 1 / 2 * offset * t^2; assuming offset is constant for the integration period)
The other problem is that you have to subtract the constant acceleration vector caused by gravitation before integrating. (and the orientation of this vector is normally not known either, unless you know the exact angle of the sensor)

Regarding the thing with the ADC reference:
The current setup uses the power supply as the ADC reference. Since the output of the accelerometer is ratiometric to supply voltage this technique gives you acceleration values independent of voltage.

As mentioned above, the Wii Nunchuk is a good way to check out accelerometers. Also mentioned is the fact that 99% of the code out there is for the authentic Nintendo Nunchuk and as is won’t work for third party Nunchuks.

I have a video demonstrating interfacing a PIC to a knock-off Nunchuk and displaying the data on a LCD:

I’m in the process of getting a website up to post the code and explain a bit more how it works.

Blinking LED is electronics “hello world” which means it works, douche

Wii nunchuck FTW! You get buttons and a joy stick with it too for under 30 bucks. :D