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Using Hacked Wiimotes As Scientific Sensors
garg0yle writes "Scientists are repurposing Wiimotes as scientific sensors to help measure wind speed or evaporation from lakes, among other things. At about $40 per unit, the controller is much cheaper than specialized sensors. The scientists are still considering how to add storage and extend the battery life."
to detect global warming?
Seems like more of an engineering challenge than a scientific one.
“There are probably better ways to measure wind, but it was a day well-spent,” Hut said. “I really felt the need to solder something.”
A day well-spent indeed! There's nothing like spending a day to save a few dollars by not having to buy a specialized sensor. Sounds like my Master's research; why buy good equipment when grad students can spend ages building a poor imitation of it? Still, those days are usually the most fun part of "science" and certainly afford excellent learning opportunities.
So if this is the future...where's my jet pack?
...this equipment can run $500 or more...
The scientific equipment is more expensive because laboratories are willing to pay more, and have the money. Gamers aren't willing to pay $500 for a controller.
Look here: Digikey has 18000 pressure sensors available. I picked one at random, and it can measure pressure up to 115 psi, which is about 60 meters deep in water. It only costs $12. I could make you the serial port/USB interface for like 20 bucks.
Scientists only pay that much because they are willing to pay that much.
I think the pricing of scientific instrumentation is based largely upon the limited number of devices produced. The folks who make sensors really do not care too much about the price and are looking at recovering their development, manufacturing and marketing costs off of very small sales quantities.
A case in point; I work with AMI (SmartGrid) systems for measuring water and electricity consumption. These devices have a surprising level of sophistication, very long battery lives (10-20 years off of a Li-Ion battery) and can store a data-point every fifteen minutes and report it back across a radio network. I "know" the manufacturing costs are down in the $30-60 range for each device. The manufacturers are all anxious to get customers (utilities) to spend their millions on projects to put SmartGrid technologies into cities so the more you buy, the cheaper they get. The data is frequently coming from "absolute encoders" on water meters and less frequently, from pulse encoders that generate a certain number of pulses per 1000's of gallons (the device counts them up, multiplies them by a K factor and gives you a corrected value for gallons of water consumed).
The Nintendo Wi is a good example. How many millions of the Wi devices are made? If they were $250 each there would not be many consumers buying them so they mass-produce and keep the prices low. You see the same effect when you hear about banks of PlayStation 3's being used in clusters for supercomputing.
Tisha Hayes
I'm curious on the non-game advances the Wii, PS3, and XBox 360 has provided for the community.
The Wii advances via it's mass-produced controller, the PS3 advances via mass-produced mini-computer, the XBox 360... um... (need some help here).
are there any details for the wind sensor? It's only mentioned in the story but not linked to any additional information.
...thats the beauty of science, we're not limited to "have to", but more what we could do - "because we can".
In amateur science circles, we also used commercially available TV-tuners as spectrum analyzers, instead of purchasing a commercial test-instrument that cost up to a 100.000 dollars, it could be made to perform pretty close and pretty well with some external circuitry for a few hundred bucks, made it affordable for the radio-amateur, science amateurs, and science students everywhere.
Absolutely LOVE to see people use the resources like the Wiimote like that, excellent!
So yeah - sky's the limit!
What this world is coming to - is for you and me to decide.
From my hours of research (read play) with a Wiimote, I'd question how accurate the data you'd get from a Wiimote would really be. Real scientific instruments can gather incredibly detailed data, and tons of it. I guess you get what you pay for.
The lab I work in uses hacked Wiimotes to study visual pecerption in autism, Alzheimer's, and Parkinson's. They can be programmed with C#, which our PI and another undergrad learned to work with the Wiimotes...the ease of use and the hackability are pretty good selling points besides the price.
Accellerometer mode is useful for things like shaking, tilting, and swinging. Sadly, it has almost nil information for determining where in space something actually is -- only how it's moving, and to back-extrapolate position from motion data is highly inaccurate.
The way Wiimotes get highly sensitive positioning data for things like aiming and driving is by using the secomd mode, whihc is the infrared sensor mode. This only works when the Wiimote is pointing at a dual infrared source (the "sensor bar" that hangs out by your TV). So if you point the Wiimote at the floor, the Wii has very little idea of how your Wiimote is actually oriented.
So what all this mumbo jumbo means for your PowerWiiGlove is that you would have to use accellerometer mode, and that it would make your glove highly inaccurate for detecting sensitive motion (such as manipulating VR objects). Your idea is highly feasible (especially with the advancements in small accellerometers that the Wiimote uses), but just not with the accellerometer configuration present in the existing Wiimote. In other words, your idea is good, but sit on it until Wii 2.0 comes out.
There's a few Wii battery packs out there that allow the controller to be powered over USB with a standard A to mini-B cable. Here's one:
http://www.dealextreme.com/details.dx/sku.4978
Of course, if you drain the battery pack faster than you can recharge it, you might have a problem.
Hands in my pocket
If I remember correctly there is a cheap ($20) addon for the wiimote that has a gyroscope in it. I would imagine that it would give a better representation of its location in space. I'm not sure though if it is an actual gyro or if it's another set of accelerometers, either way I do know that it is much more accurate with relation to its position in a three dimensional space.
"Some books contain the machinery required to create and sustain universes."-Tycho
it would sell if you had interactive pr0n games...
C|N>K
Like this one? http://en.wikipedia.org/wiki/Powerglove
;)
I remember hacking one of these as a kid when "Virtual Reality" first came out, and we did the same thing. Bucketloads of fun. Nintendo should probably review one of their previous commercial failures. At least they won't have any patenting issues.
Science advances one funeral at a time- Max Planck
It's a gyro. Really cool tech actually, in that it's completely solid state (like the accelerometers)
So what all this mumbo jumbo means for your PowerWiiGlove is that you would have to use accellerometer mode, and that it would make your glove highly inaccurate for detecting sensitive motion (such as manipulating VR objects).
Or you could stick some LED's on the fingertips of the glove and point the wiimote at them. In fact, I could have sworn someone already did something like that.
More specifically, a tuning fork gyroscope.
Apparently it is easy to read with i2c as a standalone part, too.
because why would scientists care about how accurate their data is when you can just accuse anyone questioning your study of being paid by big oil/monsanto/big pharma.
If you mod me down, I will become more powerful than you can imagine....
Like this one? http://en.wikipedia.org/wiki/Powerglove
Did you miss the subject line of the post you are replying to?
Jesus was all right but his disciples were thick and ordinary. -John Lennon
this story reminded me of this http://www.engadget.com/2009/07/08/video-wiimote-controlling-a-15-ton-grapple/ ... its amazing how many uses there are for what is marketed as a toy for children and the elderly....
I've been using them in my Computer Eng. Problem Solving class for 3 years.
Here's a vid where freshmen measure a drop (accounting for air resistance) using a wiimote.
http://www.youtube.com/watch?v=tPCBfyQP4eE
I'd say they make a great instrument as long as you quantify your error.
This is even better. and you can program your own scripts http://carl.kenner.googlepages.com/glovepie
Two wires, solar panel. Bang.
"They confiscated everything, even the stuff we didn't steal!"
Yep. That socket in the bottom of a Wiimote is nothing but a proprietary i2c interface connector. You can get accelerometer, button, and joystick input from a nunchuck with a $2.50 Atmel microcontroller. I don't know if they still have them, but sparkfun used to have a little adapter board to let you connect a Wiimote accessory to a .1" pitch 4 pin header.
While a gyro is necessary to actually do full 6-DOF position tracking (otherwise you must assume that you're holding a specific orientation... this can still be good for something like an in-the-air mouse), the Wii system still wouldn't be good for detecting absolute motion without the sensor bar as well.
The problem is that while the sensors are fairly precise as far as measuring the accelerations (if they're anything like the iPhone sensors they're around 0.02g precise), when you try and integrate them twice to get the position, things start to fall apart. Imagine you do a simple up-and-down motion. You get a sinusoidal acceleration curve that when you integrate it once gives you an offset sinusoid to represent your velocity, and a second integration gives a third one to represent your position. However, at the end, your integration to the velocity level comes out to be not quite zero, because those small acceleration errors will mostly cancel out, but not perfectly. This is still a pretty good velocity estimate, since its close to zero. However, as far as your position is concerned, close to zero and actually zero are very different, so you get a constant, growing drift in your position from a small velocity error. The same things apply to gyros, although the math is a little more complex.
Basically if you want to use a sensor as a double integrator it has to be extraordinarily precise, and even then you're going to get some drift that you have to remove every once in a while, or have an absolute position value to keep it in check (kalman filters do a great job of interpreting data from multiple sensors). What the sensor bar and IR sensors do is give you an incomplete but useful reference on position and orientation that you can use to keep that drift in check. Adding the gyros definitely helps a lot too, but you still need the sensor bar to keep drift in check.
I work with a number of professors at several universities, and they have to pay their grad students for time spent on the projects we fund. I don't know what the hourly rates are but they're enough that when one project temporarily ran out of funding, the grad student took a job waiting tables at a restaurant. This suggests that the pay is in a similar range as what a waiter makes. Not a lot, but not $0 either.
I remember it well because the prof told me that when he got his next funding increment he had to go down to the restaurant and get his grad student to come back.
If you're a grad student and you're doing research work for $0, well, I hope the work will look really good on a resume.
Putting moderation advice in your
Solution: collaborate.
I know, I know. Obviously beyond any real-world scenario in academia.
Actually, collaboration is very strong in US universities. At work we are constantly hearing about some research project or other being helped out by someone from a different department who brings new or unique skills or methodologies to the project.
What is not favored however, is falling behind schedule on your grant-funded research because you're waiting for some weenie to hack together an experimental sensor from scratch when you can go down to Gamestop and buy one for $39.
Putting moderation advice in your
I've seen other demos of using wiimotes for other purposes. Such as taping it to a google headseat for a semi-VR experience.
"You'll get nothing, and you'll like it!"
The wiimotes are being used to keep this article on the front page for days!! I keep refreshing and nothing new comes up - and this is from both my home and work computers. What is going on in Slashdot land?
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