Friday, December 29, 2006, 09:59 AM - Misc TechnoToysAstrophotographer Thierry Legault took this amazing picture of the International Space Station and the shuttle Atlantis passing in front of the sun. The exposure was so short (1/8000s) that atmospheric disturbances did not have time to blurr the image. You can see all the details of the ISS, and the tail of the space shuttle from 550Km away!
Speaking of astrophotography, here is a list of the top 10 astronomy pictures of 2006, and here is a nice web site with several beautiful pictures of the sky (not necessarily astronomical).
Thursday, December 28, 2006, 09:23 PM - Misc TechnoToysA couple random sites of Math jokes here, and here.
Q. Where do adders (a common snake in England) multiply?
A. When they are in logs.
Wednesday, December 27, 2006, 01:49 AM - Roboticswww.hei-rc.de has this long list of links to amateur web sites for telemetry, auto-pilots, and other UAV-related stuff.
Wednesday, December 27, 2006, 01:16 AM - RoboticsThe OpenServo project proposes turn a cheap analog servo into a high-performance, programmable digital servo by replacing the circuit board with a custom board built around an Atmel AVR-8 micro-controller. The servo includes I2C control with position/force feeedback.
Wednesday, December 27, 2006, 01:06 AM - RoboticsThe ChRoMicro helicopter autopilot project uses a Gumstix Connex board. The Gumstix are tiny computers running Linux that are built around a Freescale PXA255 ARM processor.
The software part of the ChRoMicro, called pxaRC, has its own web site. Other goodies include instructions and software to connect a CMOS camera to a Gumstix Connex board.
Wednesday, December 27, 2006, 12:45 AM - ElectronicsFrench author Francis Thobois has published numerous articles on how to build your own R/C set since the early 60's. His web sites has instructions for building receivers, transmitters, and various R/C-related circuits. Some of his pages have been translated into English.
Wednesday, December 27, 2006, 12:31 AM - RoboticsApeliotes is an autu-pilot for UAV that uses a 3-axes magnetometer. This allows the UAV to measure its attitude using the Earth's magnetic field. Unlike gyro-based attitude estimations systems, magnetometers are not subject to drift.
This was a project conducted by Matthew Chave at University of Otago in New Zealand. The board is built around a Philips LPC-2129 microcontroler (with an ARM-7 processor core). The project report is available.
The project web site is being moved to www.uavdev.com, but the new site is still in construction.
Wednesday, December 27, 2006, 12:14 AM - RoboticsMicroPilot sells a miniature auto-pilot for UAVs that weigh only 28 grams, on a 10x4 cm board that includes a GPS, Gyros, airspeed, and barometric altimeter. The price is not light: the cheapest model, the mp1028g, is
$1700, if you buy 100 of them.
Tuesday, December 26, 2006, 01:55 PM - Flying ContraptionsDonuts Models is a French manufacturer and reseller of R/C equipment for indoor and 3D flying.
Their Aito V2 indoor biplane is particularly succesful and popular. The specifications are: wingspan: 890mm, mass: 160-200g, wing loading 4.9-6.2 g/dm^2, motor: AXI 2204/54, 3 servos (6 gram type), battery: 500mAh 2-cell LiPo, prop: GWS 9x4.7. The website has a video of the plane in action, flown by Jerome Chambon.
Last summer, I met master pilot Philippe Noirault at his usual indoor flying spot in Pleslin (in Brittany, France), and took a picture of his Aito, as well as a couple of videos. The Aito is the plane of choice for Philippe and his friend Nicolas Fratti in F3P competitions.
Tuesday, December 26, 2006, 01:27 AM - Misc TechnoToysGerman vision scientist Michael Bach has a huge collection of amazing optical illusions. Well worth a (prolonged) look.
Monday, December 25, 2006, 11:19 PM - Flying ContraptionsSwiss pilot Yves Rossy designed an impressive rocket pack. The website has a video of Rossy flying around the Swiss mountains. The system is composed of a wing that is unfolded in flight (after jumping from an airplane) with a 3 meter wingspan. It is powered by four German-made JetCat mini-turbojets designed for model airplanes that gives it a pretty good climb rate. The wing seems to have no control surface and appears to be controlled by weight shifting. Given its shape and tail-less design (a pure swept-back flying wing), the wing must be "twisted" so that the tips have a lower angle of attack than the center section (to ensure stability).
Rossy can fly under power for about 5 minutes, at speeds between 120 and 300 km/h, and a climb rate of 1000 ft/minute (at 180 km/h). The landing is done with a parachute, with the wings folded.
The next prototype is slated to allow vertical climbs and aerobatics.
There are also a few videos on YouTube.
The largest JetCat turbines have a thrust of 220N, and a weight of 2.4Kg. Five of those turbines would give 112Kg of thrust, which is barely enough to allow vertical climb. At least, your wallet would be lighter... by about 24,000 Euros.
Monday, December 25, 2006, 10:42 PM - Flying ContraptionsSelective R/C makes the Black Knight R/C helicopter. The heli comes with a radio, 2 servs, a gyro, and an NiMH battery. This is all unremarkable, except that you can get the whole package for $130 at Hobbytron.
Hobbytron also has a collective pitch 3D model for $210.
BPhobbies also has the E-Sky HoneyBee ready-to-fly heli for $130.
A review of the Black Knight 2SE at RC Universe says it is easy to upgrade the heli with LiPo battery and a brushless motor using upgrade kits for the virtually identical (but slightly more expensive) Venom Night Ranger 3D from Venom Aircorps. The Venom Night Ranger 3D is available at Tower Hobbies, and at HobbyZone for $220.
Sunday, December 24, 2006, 02:18 AM - Flying ContraptionsBob Aberle, a pioneer of micro R/C flying, wrote a nice tutorial on micro R/C equipment and indoor flying, listing lots of suppliers and manufacturer. The tutorial is hosted on the Cloud9 / RC Micro World newsletter web site, maintained by other micro R/C pioneer John Worth.
Sunday, December 24, 2006, 02:13 AM - Flying Contraptionsmicroflierradio.com, the web site of micro R/C modeler Nick Leichty has a couple of planes in the 1 gram range. Nick sells motors, radio equipment, and actuators to build those planes.
Sunday, December 24, 2006, 01:44 AM - Flying ContraptionsBob Selman Design has a bunch of tiny outrunner brushless motors weighing 4 to 8 grams.
These motors and a few others can also be obtained from Sky Hooks and Riggings in Canada.
Saturday, December 23, 2006, 09:36 PM - Misc TechnoToysI won't say more. Go there, pick an example, stare at dot in the middle of the picture for 20 seconds. Then, keeping your eyes fixed, move your mouse on the picture.