Monday, October 8, 2007, 01:46 AM - ElectronicsOver the last few months, I have become rather fond of the Arduino microcontroller board concept. I like its simplicity, its open design, and (last but not least), the fact that the development environment runs seamlessly on Linux.
One shortcoming of most Arduino boards is that they are rather bulky (not good for putting them onbard a small airplane). While the Arduino Mini has been available for a while, it is not as convenient as the new $17.50 Boarduino kit from Ada Fruit.
The Boarduino has everything a regular Arduino has, but it is much smaller and can plug into a breadboard.
Monday, October 8, 2007, 01:07 AM - ElectronicsSpeaking of Jeff Han: Jeff pointed me to this new device, recently announced by Analog Device. Many people were anxiously waiting for something like this to appear: single chip that contains 3 accelerometers and 3 gyroscopes that can be used to build a full, 6 degree of freedom inertial measerument unit (IMU).
The part is called the ADIS16355.
It uses an SPI interface, and even includes an auxillary 10-bit A/D converter, an auxillary D/A converter, and two digitial I/O
(see data sheet).
Now for the bad news: the price is $360 in 1000 quantity (ouch!).
It's still a lot cheaper to buy a 5 DoF break-out board for $110 from sparkfun (3 accelerometers, 2 gyros), plus another gyro, and a cheap micro-controller.
Monday, October 8, 2007, 12:51 AM - Misc TechnoToysMy friend and colleague Jeff Han has been getting a lot of attention in the last year or two with his amazing multi-touch display panel (see various videos here and here, and
his August 2006 TED talks)
Jeff has started a company in New York City called Perceptive Pixel.
The funny thing is that the upscale department store Neiman Marcus is offering Jeff's "online media wall" in the "fantasy" part of its Christmas catalog. The price is "starting at 100,000". If you have to ask.....
There is a nice video on the Neiman Marcus site too.
Monday, October 8, 2007, 12:18 AM - Flying ContraptionsBattery manufacturer A123 Racing is offering a new type of Lithium-Ion batteries for model cars and airplanes that can not only put out enormous amounts of current, but can also be charged in 15 minutes.
A123 Racing is a sub-brand of manufacturer A123 Systems, who has been producing the new type of battery for a while. They were so far mainly used in rechargeable cordless drills.
The so-called Hypersonic cell has the following characteristics: capacity: 2300 mAh; nominal voltage: 3.3V; internal impedance: 10 milliohms; max continuous discharge: 70A (30C); burst discharge (10 seconds): 120A (60C); fast charge current: 10A (4C), which translates into a charging time of 15 minutes; mass: 70 grams; price: $20.
A 3S1P pack costs $90, and the special charger is roughly $100.
The energy per gram is not as good as a LiPo, but you can't beat the charging time....
Monday, September 10, 2007, 06:31 PM - Misc TechnoToysStartup company EEstor claims to have produced ultra-capacitors with en energy density of 280 Watt-hour per Kilo. When you realize that your typical LiPo battery is around 140 Wh/kg your interest level goes up a notch. Given that ultra-capacitors can be charged extremely quickly (in seconds), and have a huuuuge maximum current, this might just be the miracle power source, not just for model ariplanes, but also for (full-scale) cars, which is EEstor's main target.
The main limitation of garden-variety ultra-capacitors (the ones you can get from DigiKey) is that they have a very low breakdown voltage (like 3V). The energy per unit mass sucks. It's enough for those e-charger toy airplanes from AirHog with a 10 second running time, but not for R/C planes. Since the energy stored in a capacitor is quadratic with the voltage (1/2.C.V^2) increasing the breakdown voltage can make a big difference. That's apparently what EEstor has done: they were able to raise the breakdown voltage to 1500V....
EEstor doesn't really have a web site, but there was a nice article on them at Technology Review back in January.
Monday, September 10, 2007, 06:29 PM - TechnoToysAfter a long hiatus, Yann's Techno Toys is back in business.
A large backlog of Techno Toys awaits us.
Friday, May 18, 2007, 01:49 AM - Flying ContraptionsPaparazzi is an open source hardware/software project whose goal is to provide a complete autopilot system for UAVs.
The Paparazzi project is hosted at the "Ecole Nationale de l'Aviation Civile" (ENAC) in France, and is the basis of ENAC's autonomous UAV project.
The hardware is built around a Philips LPC2148 ARM-7 chip. It includes a GPS and Pyro-electric infrared sensors for pitch and roll angle detection (no gyros).
Friday, May 18, 2007, 01:25 AM - Flying ContraptionsCrespiere 2007, an annual get-together of electric R/C airplanes in France, took place last week. I'm told the weather was sub-optimal (very high winds), and the turn out less than usual (because of the weather). Web magazine RC Pilot Online has a picture gallery of the event.
I was intrigued by this weird-looking plane that looks like a Calder scultpure.
There is also a picture of my dad's new CAP-10 . Unfortunately, bad weather prevented test flights before Crespiere, hence it didn't fly during the event.
Tuesday, April 3, 2007, 01:26 AM - Flying ContraptionsTrek Aerospace has demonstrated a small, electric powered UAV called the OVIWUN. It has two contra-rotating ducted fans on each side of a "fuselage". The ducted fans can be independently tilted forward or backward to control yaw and pitch (as well as forward/backward translation). Roll is apparently controlled by changing the relative speed of the rotors. Each rotor is powered by a 450 Watt electric motor. The UAV is 36cm tall, 65cm wide, 41cm long, and weighs 2520 grams (with batteries). They claim an endurance of 20 minutes, and maximum speed of 75km/h (which I find very hard to believe).
The $15,000 price is a bit steep for something many of us could probably build in our shop. However, the good news is that UAV is controlled by an Xscale-based single-board computer running Debian Linux, and comes with open source flight control software.
There is a nice video of the OVIWUN's indoors test flights
Monday, March 19, 2007, 01:00 AM - Flying ContraptionsThis page has a collection of papers by the participants of the 2006 student competition of Unmanned Air Vehicles. There is quite a lot of details about the hardware used in each of the participants' planes.
Monday, March 19, 2007, 12:47 AM - ElectronicsProcerus Technologies offer the Kestrel micro UAV auto-pilot. It weighs 16.5 grams and contains a 6 degree of freedom inertial measurement unit, a magnetometer, an absolute and differential altitude sensor, and an airspeed sensor. It's built around a Rabbit micro-controller. The only thing that's not light about it is its price: 5 kilodollars.
Sunday, March 18, 2007, 11:28 PM - Flying ContraptionsMy friend Jeff Han recently went to the TED Conference and brought back one of Wowwee's new Flytech R/C Dragonflies. I tried it out and took a few close-up pictures.
The dragonfly flies quite nicely. Its control system is somewhat unique: it has a small propeller on the tail (spun by a pager motor) to pull the tail to the left or to the right. It has a "beginner" mode and an "expert" mode. In beginner mode, the Dragonfly turns rather sluggishly, but in expert mode, it is quite maneuverable. However, it loses a lot of altitude in tight turns, so flying in cramped spaces takes a little bit of practice.
There are 4 wings, but they actually are rigidly attached in pairs. The pairs oscillate in opposite phase as shown on this picture.
The LiPo battery is recharged in 25 minutes (probably not to full capacity) by plugging the Dragonfly into the transmitter. A magnet hods it still on the transmitter.
More pictures are available here.
The Dragonfly is available from Radio Shack for $50.00
UPDATE: Doug Setzer points us his DragonFly forum, and to this photo series that shows the innards of a dissected DragonFly.
Thursday, March 8, 2007, 10:46 PM - Flying ContraptionsSpinMaster came out with the Reflex R/C Helicopter. Like many recent toy R/C helicopters, the reflex has two contra-rotating rotors for stability. The new twist is that it has two "thrust" motors and prop (one on each side of the body) to make it move forward, backward, and to rotate. They claim an un-precendented maneuverability, which I can believe. It has to be easier to control than the Picoo-Z and AirHogs's own Havoc.
The price is $70.
Thursday, March 8, 2007, 03:04 PM - RoboticsACME Systems in Italy is selling the FOX Board, a tiny 66x72mm, 37gram board built around the ETRAX 100LX CPU from AXIS Communications. The board runs Linux 2.4.x or 2.6.x.. It has USB, Ethernet, and can support webcams through the spca5xx-le driver. It sells for 130 to 150 Euros, depending on the version.
The FOX Board can accept a daughterboard called FOX VHDL which has a 250K gate Actel ProAsic3 FPGA. Hmmm....
Some people have done pretty cool things with the FOX Board, including this hexapod robot.
Thursday, March 8, 2007, 02:43 PM - RoboticsFor some time now, Charmed Labs has been selling the Qwerk embedded robot controller ($350). It has a rather unique combination of features: ARM9 CPU with FPU, Linux and eCOS operating systems, a Xilinx Spartan 3E FPGA for fast custom I/O, ethernet, Wifi, USB ports with Webcam support, 4 DC motor controller (2.0 Amps), 16 servo outputs, 8 Analog inputs (12 bits), 16 digital I/O lines, quadrature encoder inputs. The software was developed at CMU. The Qwerk is the basis of CMU's Terk Telepresence Robot Kit.
Thursday, March 8, 2007, 02:20 PM - RoboticsMichel Xhaard has developed spca5xx-LE, a lightweight version of the spca5xx USB webcam driver for Linux. This driver is useful for using webcams with embedded linux boards such as the FOXboard (based on the Axis ETRAX 100LX CPU).
Michel also maintains this list of webcams supported under Linux, particularly those supported by the spca5xx(-LE) driver.