Mindboards

I lurk in the Picaxe forums and LMR as well as MindBoards. A while back I saw an interesting post on LMR about using the IR camera out of a WiiMote to track various IR emitting objects like candles or IR LEDs. However, since I didn't have a WiiMote and I didn't want to risk wasting $40 US (then, now $30) on a new WiiMote and since I don't have a 'duino, I just forgot about it. A couple days later, I find an Instructable on the same subject. Same thing, read and forget.

Fast forward to today. I read a post on the Picaxe forum, pretty much about the same thing. Except with Picaxe, which some would say isn't quite as powerful as the Arduino. Which got me thinking... why not with the NXT? RobotBox did something like this with the Neato Lidar project. Except that they offered bounty, the only "bounty" I'm offering is the idea. The price of a basic WiiMote (in case you haven't heard, the WiiMote has been updated, new one now contains the Motion Plus in the WiiMote) has dropped to $30 US new, but you can easily get used ones for under $20 US and since your taking it apart anyways, why bother getting a new one?

I'm seriously thinking about getting one, just to play around with. I just hate spending money on more projects when I haven't finished the ones I have going already... . Think of the possibilities: a IR Seeker V1 for less, with more power and more possibilities. So, if your up to a little coding, go steal your friends/cousins/brothers/childs WiiMote and tell us how it goes!

I can recommend the wii remote for tracking purposes very much! I used two devices for my resarch: 3D motion tracking. I basically re-coded, cloned and modified this project and sourcecode (my version runs in plain MATLAB with a DLL/.net library loaded): http://www.cl.cam.ac.uk/~sjeh3/wii/

There are many many many libraries and packages (sort of custom "drivers") that get the Wii data into your computer. WiiYourself!, cwiid, WiiLAB, WimoteLib, and more. It works well on Linux and Windows systems (didn't try a Mac). I used my standard Bluetooth dongle and laptop with Ubuntu, and from my bad NXT Bluetooth experiences, I was really surprised: It all worked flawlessly out of the box.

The camera of the WiiMote can track up to 4 IR sources at the same time. It always takes the 4 brightest ones. You can get intensity / size and the bounding rect. The effective resolution is 1024 * 768, at 100 FPS!!! Try that with webcams! Although you CAN actually easily produce an IR filter for webcams (but that's another topic).

As I said before, I could successfully get 3D tracking with 2 Wiimotes working. The only (small) disadvantage: The opening angle (FoV: field of view) is very small, if the cams are too close, you can't see that much...

Anyway, there are many papers on this (just use google scholar and the keywords "wii tracking"), if there's interest I can provide many of them.

The best starting point is to look at Johnny Lee's original work and his famous Youtube videos:
http://johnnylee.net/projects/wii/


Oh, and if you wan't do navigation with the Wiimote, I could suggest you have a look at this ingenious project: http://www.ra.cs.uni-tuebingen.de/forsc ... ome_e.html

Oh, and since the cam inside the Wiimote uses I2C (to get the IR-target coordinates), you can probably hack together an interface to talk to the cam from the NXT directly. However, I'm not a hardware guy, so somebody else should have a look

Wow, thanks for all those links! I was thinking more along the lines of hacking the sensor apart to get at the camera inside, but all your links are very interesting. The last one was especially interesting, considering SparkFun's project post today. I'm starting to think along the lines of a NXT quad-rotor... too many ideas and not enough time .

nxtreme wrote:Wow, thanks for all those links! I was thinking more along the lines of hacking the sensor apart to get at the camera inside, but all your links are very interesting. The last one was especially interesting, considering SparkFun's project post today.

Wow, thanks for this news. I've seen other videos of those people (the GRASP lab), like http://www.youtube.com/watch?v=MvRTALJp8DM and http://www.youtube.com/watch?v=YBsJwapanWI

Another similar project is the Flying Machine Arena of ETH Zürich: http://www.idsc.ethz.ch/Research_DAndrea/FMA

But, sorry, didn't want to derail this thread.

nxtreme wrote: I'm starting to think along the lines of a NXT quad-rotor... too many ideas and not enough time .

There were many discussions about this, mostly on nxtasy. The NXT motors can't deliver enough mechanical power for such a "heavier than air hovering flight". It's a very very close call ifyou want to do a "gliding flight" (like a plane), but you would need extremly light and wide wings (probably > 3m span) and some good propellers.

Anyway, using the Wiimote is far more realistic, and nice. And remember: Not only do you get this nice IR tracking cam (which can also track regular lights btw, if you remove the IR filter from the remote), you also have an accelerometer and speaker.

linusa wrote:Wow, thanks for this news. I've seen other videos of those people (the GRASP lab), like http://www.youtube.com/watch?v=MvRTALJp8DM and http://www.youtube.com/watch?v=YBsJwapanWI

Another similar project is the Flying Machine Arena of ETH Zürich: http://www.idsc.ethz.ch/Research_DAndrea/FMA

But, sorry, didn't want to derail this thread.

Yes, the GRASP labs have done pretty much everything! From UAVs to AGVs to "smart" wheels chairs. And don't worry about derailing the thread, I don't mind as nobody seems to be quite as excited about a I2C IR object tracking camera for less than $20 US as I am...

linusa wrote:There were many discussions about this, mostly on nxtasy. The NXT motors can't deliver enough mechanical power for such a "heavier than air hovering flight". It's a very very close call if you want to do a "gliding flight" (like a plane), but you would need extremly light and wide wings (probably > 3m span) and some good propellers.

Anyway, using the Wiimote is far more realistic, and nice. And remember: Not only do you get this nice IR tracking cam (which can also track regular lights btw, if you remove the IR filter from the remote), you also have an accelerometer and speaker.

I was thinking more along the lines of having the NXT and some sensors like Accel, Gyro, Mindsensors cam for object tracking, US sensor ect. all controlling some brushless ESCs through the Mindsensors RC servo controller. However, I know that this is rather impractical as I am into RC airplanes (just got a T-28 Trojan for Christmas, boy is it fast) and something as heavy as the NXT would almost need to be put in a hexrotor just to keep it in the air, unless you got some pretty big motors and props.

Yes, I do agree about the WiiMote. I wonder if anyone has successfully connected the WiiMote directly to the NXT instead of having a PC act as the go-between? I mean, through Bluetooth, instead of hacking it apart like my original idea. It seems a shame to include a PC when the NXT is so powerful by itself...

mmhmm, I very much like where this post is going, yes I do.

So, the real question is: can you connect the WiiMote (via BlueTooth) to the NXT? I don't have a BlueToothconnection on my computer (but my bro's laptop does....) so if that could be done I'd start doing it immediately. I happen to have one of the newer WiiMotes with MotionPlus built-in, so 2x accel = 2x fun!

Also I like that you can remove the IR filter and have a nice little camera, but I doubt I'll be doing that much.


On a final (and possibly off-topic note): does anyone know how much of the WiiMote you can control via BlueTooth? Not only do you have a speaker and RumblePak for output, you also have four ultra-bright blue LEDs that could be fun to play with (or use as status indicators, etc.). If anyone knows about these things (direct WiiMote->NXT connecivity via BlueTooth; what you can control on the WiiMote via BlueTooth), I would be very happy to read as much as possible about it. (I might even start working on a way to mount the WiiMote to the NXT....)

Good to see someone is interested, even if you'd not connect it directly to the NXT. It is not possible to connect the WiiMote directly to the NXT because it uses the HID protocol (or, should I say, a very abused version of the HID protocol) and AFAIK, the NXT only supports SPP. That is why I like the idea of hacking the WiiMote directly to the NXT, because you don't need a computer in-between which I think sorta defeats the purpose of a robot (unless it's not mobile).

I don't know exactly how much of the WiiMote you can control, but there are several websites that explain it in detail (WiiBrew comes to mind). You may find this post on LMR interesting, something similar might be done with the NXT, although I'm not sure that'd be very useful at all, as the NXT can already talk to a computer.

Awesome, I clicked through some of the links on the WiiBrew site.... You can definitely control the speaker, LEDs, and vibrator.

nxtreme wrote:I like the idea of hacking the WiiMote directly to the NXT, because you don't need a computer in-between which I think sorta defeats the purpose of a robot (unless it's not mobile).

I would love to have a WiiMote->PC->NXT connection, I would want to use the WiiMote because it is wireless. To connect it to an NXT you have to have (AFAIK) wires, so that kinda defeats the purpose for me. And, compared to a 'bot plugged into your computer, a 'bot on BT is mobile.