Posts Tagged ‘Robotics’

Wiilson: Wii-Skybot extreme (Skybot + Wii + PWM)

A couple of days ago I mentioned this in the post about extending libStargate for a class assignment we had. The team was formed by Miguel, Gonzalo and myself, and we received a pretty good grade, by the way. I wanted to write again after having some patches sent to the main author of libStargate by the end of this week, but it turns out I won’t be able to properly test them until after that. Since a lot of friends have been having problems with their own projects, ours is going to be temporarily cannibalized until their time is up. Wish them luck! ;)

Anyway, I’ll post again once  I have the things properly tested and I’ve spoken to the people of IEArobotics. For now, here is the link to download Wiilson if you want to try it out.

As mentioned earlier, it is just a PWM Wiimote implementation to control a Skybot. The Wiimote is interfaced thanks to the excellent pywii library, Orienting the Wiimote makes the bot move and it goes faster or slower depending on the inclination of the controller. Changing from mode ‘A’ to ‘B’ (or ’1′ to ’2′) overrides this behavior and controls the bot with the direction keys of the Wiimote, being able to alter speeds with the ‘Plus’ and ‘Minus’ buttons. It’s not pretty, but it is a quick hack and works fine. If you want something better you’ll have to wait for the release of pybot, a Python module to control (extended) libStargate managed robots with PWM support. The only class present right now is to control the Skybot as it is out of the box, so PWM support is software based -you’d have to rewire it if you wanted a hardware version of this, much better but totally out of the scope-.

Coming up soon, at least as soon as our bot gets de-cannibalized if that is even a word!

By the way… I think I’m getting to love this stuff. I’ll have to buy a Skypic or Arduino for myself. You can’t ever play around enough with these things. And to think it was always there and I never knew!

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Skybot, take two: extending libStargate

In a previous post I mentioned that we would be playing around with a bot project to interface our Skypic board and the Wiimote as an assignment in class.

Hacking these things has been fairly easy thanks to some pretty handy pieces of software we stumbled upon at IeaRobotics and a bit of Python magic. The tools of the trade were Pydownloader to program the Skypic, libStargate to interface the PC and the bot, and finally Pywii, a wonderful Wiimote library.

We ended up implementing a new server for the Skypic that should enable a smooth control of the acceleration applied to the Skybot in response to the Wiimote’s movements. To handle it we had to extend libStargate. Our job wasn’t particularly hard to do, but up until now you only had the chance of applying an all-or-nothing type of movement. Now the acceleration is proportional to the pitch and roll values of the controller. Since the controlling code is in the PIC instead of the computer, the effect is really smooth.

The bot has dual power. 6V for the Skypic and 9V for the servos. If only we had used 12V for these the effect would be nicer yet, but overall its fine.

I’ll clean the code a bit before submitting the patches to the project’s author, and I hope to have it ready and submitted this week along with a new wrapper class around libStargate to control specifically the SkyBots with PWM capabilities. It is called pySkybot, by the way.

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More on the wonders of Wii

Following up a post about the Wiimote, here is something interesting I stumbled upon. It’s also about cheap 3 axis accelerometers, only this time it isn’t about the Wiimote. It is about the Wii Nunchuk. Check this out!

You can see the whole story at Hackaday. Although I’m not really used to hacking with circuits, I do check some of these sites on a regular basis. And I must say every now and then they come up with things that make me wish I were Ajo ;-)

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