Thursday, May 14, 2009, 07:06 PM - Flying ContraptionsThere seems to be a renewal of interest in the heretofore abandoned concept of the cyclogyro
The cyclogyro has two rotating sets of "paddles" whose angle of attack is cyclically modified to create lift in the desired direction. The principle is well described by the animation in this Wikipedia article.
There is a YouTube video of a thethered micro-size cyclogyro, which was designed at the National University of Singapore. A detailed description of the design is available here.
A team of Japanese roboticists has apparently revived the concept, using a "pantograph" mechanism to vary the angle of attack (link to IEEE Tans. Mechatronics article),
and a short description with pictures on PhysOrg.
I'm somewhat doubtful of the efficiency of the design, but it looks like a fun thing to build.
There is a number of article on the web that describe 1930's designs for cyclogyros. I am somewhat surprised that none of these designs seem to include an anti-torque system. These paddles are bound to generate a high torque that would make the vehicle pitch up (which is why the cyclogyro on the YouTube video has a propeller in the back).
Thursday, May 7, 2009, 11:39 PM - RoboticsThis past semester, I have been teaching an undergraduate course Introduction to Robotics. The first series of assignments included programming Arduinos to read sensors and actuate servos and DC motors. The second series included programming a Pololu 3Pi robot to follow a line (using a PID controller), and perform dead reckoning (coming home after following a line to its end).
The last series of homework consisted in getting Rovio robots to play soccer. I feel I should mention this here because the class page showing videos and pictures of the students' soccer-playing Rovios had been mentioned by a number of blogs, including Slashgear and RoboCommunity.
The Rovio robots can be seen as "Wifi webcams on wheels". The goal of the project was to push a tennis ball into a goal. The tennis ball is bright yellow, and the goal posts are red. The rovios are controlled by software running on a laptop which performs the vision and control algorithms. The software is written in our very own Lush language, which is a dialect of Lisp.
Wednesday, April 1, 2009, 12:57 AM - JazzTonight at La Lanterna in NYC tenor sax Bill McHenry was sitting in for Joel Frahm, with bassist Joe Martin and drummer Bill Campbell. They played two of Bill McHenry's new compositions "Violetta" and "Lines" which I thought were particularly interesting.
Thursday, March 26, 2009, 03:00 AM - Misc TechnoToysLumenlab proposes the micRo CNC kit for $500 for a partial kit and $1000 for a complete kit. You can also get a low-end Dell PC to control the CNC machine for $330, pre-configured with Ubuntu.
The total travel dimensions are 34cm x 25cm x 8.9 cm.
[via Makezine blog]
Thursday, March 26, 2009, 02:50 AM - ElectronicsThe Makershed has a new XBee adapter for $10 with 10 pins, some which directly fit in an FTDI serial USB adapter cable. It includes level shifters and a 3.3v regulator and can be plugged into a proto board.
Newmicros also has an XBee USB dongle, for $40.
Saturday, March 14, 2009, 09:09 PM - ElectronicsIntelspy sells a surveillance system with two wireless cameras and a 2-channel receiver for $130. The interesting thing is that the claimed range is over 500m.
Saturday, March 14, 2009, 09:00 PM - ElectronicsA cool little hack in which an Arduino is used to levitate a magnetic object and regulate its distance from the levitating electromagnet.
Monday, March 9, 2009, 10:04 PM - ElectronicsThis page has a bunch of interesting prototyping shields for the Arduino, including relays, power FETs, motor drivers and such (via Makezine blog).
Thursday, March 5, 2009, 07:47 PM - Flying ContraptionsMicro RC manufacturer Plantraco has a Ready-to-Fly 1/72 scale RC Spitfire, with a wingspan of 15cm, and incredible weight of 2.7 grams. The plane is available for $99 including the radio. It uses a 4mm coreless motor with a 32mm prop, a 0.38g 2channel receiver (rudder and throttle), a 0.07g rudder actuator, and a 0.95g 20mAh lipo battery.
Sunday, March 1, 2009, 01:52 AM - Misc MusicI just noticed this nice Akai EWI 4000s patch editor/librarian app called EWItool. The best part is that it runs on Linux (as well as on Windoze). There is a pre-compiled debian package too.
It can automagically fetch patches from EWIpatchExchange.
Monday, February 23, 2009, 01:28 PM - Misc TechnoToysThe WRAM show is an R/C modeling trade show that takes place every February at the Westchester county center in White Plains, north of the New York City. The show usually occupies two floor and the booths are filled with manufacturers, importers/distributors, and retailers showing their exotic gear. This year however, the show was rather disappointing and occupied only one floor. Many of the manufacturers that usually have a booth were absent, and many of the big on-line retailers like Hobby Lobby and BP Hobbies were absent. It looks like the economic crisis is having an impact.
- Trace En Poche (which could be translated as "pocket plotter") is an amazing on-line tool geometry, kinematics, and plotting tool. It allows you to enter descriptions of geometric figures using a GUI or a simple description language, and to plot and animate the result. The tool is available in a number of languages (French, English, Spanish, German, and Arabic). Thanks to Bertrand for the pointer.
- Command-line-fu: a bunch of random semi-non-obvious Unix/Linux command-line idioms to do various useful tasks. These simple tricks will occasionally aleviate the need to plow through the man pages of find, awk, egrep, sort, and such.
- Diamonds in the Sky: a collection of scientifically correct astronomy-related science fiction stories (sponsored by NSF).
- GPS homing device: Hammacher-Schlemmer has a simple GPS homing device for $80. Press a button when you are at a particular location, and the device will keep track of the distance and bearing to that location. It's small and simple to use. It integrated a self-calibrating digital compass in addition to a GPS.
Friday, February 20, 2009, 12:28 AM - TechnoPoliticsI went to see Universal Robots, the play by Mac Rogers at the Manhattan Theater Source yesterday. It's a fantastic play, very clever. The play is quite long (about 2.5 hours, or 3 hours including the intermission), but it is riveting from beginning to end. Each little dialogue and detail that seems gratuitous at first turns out to have major consequence for the future of humanity. The play feels like an elaborate scaffolding in which every small part plays an important role in keeping the construction together.
Practically every moral, social, and political issue raised by the possible emergence of intelligent robots is raised during the play: the military funding of scientific research, the political control of a unique and powerful technology, the role of human labor in an automated world, robotic wars, robot pain, robot morals, robot love, robot compassion, robot sex....
Go see the play. It's on until March 7 (and come to the panel discussion on Saturday Feb 21 at 3:00PM).
Tuesday, February 17, 2009, 02:53 AM - RoboticsThanks to Laurent Pinchart, maintainer of the uvcvideo driver, the Minoru stereo webcam now works on Linux.
If you are in a hurry to get it to work, here is the installation process under Ubuntu (or any Linux distro with kernel version 2.6.27-xx):
0. make sure you have installed the linux-headers package, probably called linux-headers-generic.
1. download Laurent's latest driver from linuxtv.org (click on the .gz link near the top of the page).
2. do "tar xvf <the-file-you-just-downloaded>". This will make a directory named "uvcvideo-XXXXXXX" in the current directory. cd to that directory.
3. do "make", and "sudo make install".
4. plug in the Minoru webcam.
The left and right webcams will appear as /dev/video0 and /dev/video1 (unless you already have a video device plugged in). You can grab from both cameras simultaneously at 640x480 at 15 frames per second, or 320x240 at 30 frames per second.
Thanks to Laurent for the quick fix, to Jan Ciger for testing the patches, and to Steve Jamieson and David Holder from Minoru for being supportive.
Friday, February 6, 2009, 11:06 AM - RoboticsThe Manhattan Theater Source in Greenwich Village, just north of Washington Square Park (and two blocks away from my lab at NYU) will host the play Universal Robots, a liberal adapation by Mac Rogers of Karel Capek's classic play R.U.R. ("Rossum Universal Robots", this is where the word "robot" comes from). The play will run from Feb 12 to Mar 7.
A Panel discussion will take place on Feb 21st from 3:00 to 4:00 PM entitled Resistance is Futile: Exploring our Evolving Relationship to Robots in Today’s Wired World. Panel participants will include my friend Michael Littman (from Rutgers), and yours truly, as well as artists and scifi writers.
Sounds like fun.
Saturday, January 31, 2009, 04:29 PM - Misc TechnoToysI just received one these brand new Minoru stereo webcam, which I bought at Amazon from 90 bucks (a steal considering the price of the closest competitor).
Naturally, I'd like to use it under Linux for robot vision, so I was crossing my fingers that one of the webcam drivers on Linux would recognize it.
As soon as I received the camera, I plugged it into my laptop running Ubuntu 8.10 Interpid. There are good news and bads news.
Good news: the device is detected by the uvcvideo driver, and the left and right cameras appear as /dev/video0 and /dev/video1. My video grabbing software was able to grab frames from both camera separately. I tried my own video grabbing test program written in Lush for v4l2.
Now for the bad news: it seems impossible to grab video from the left and right cameras at the same time :-(
It looks like uvcvideo assigns more than half the USB port bandwidth to the first camera, and there is not enough left for the second. I've posted a question about the problem on the uvcvideo developer mailing list. Stay tuned.
UPDATE: Laurent Pinchart, maintainer of the UVC driver is looking into the problem. It looks like the camera reports a higher bandwidth than it needs (at least, that's what how the driver interprets the data). The Minoru people are interested in making their camera work with Linux and are helping out Laurent (sending him a free camera and such).