Blogs

I have finished my Arduino based pulse width modulated (PWM) hot wire cutter controller. It allows precise USB or analog temperature control of a hot wire of length from 10cm to 2m for use with manual cutters or CNC based cutter. The PSU is extermal (battery or PSU) The 12v power is attached to the GND and + 12V terminals. The + to the hotwire is attached on the red terminal on the top. The current return thru the FET is connected to the black return terminal. An FTDI board can be attached to the Arduino thru the "programming window".

What do you think :) ?

A big milestone for DIY Drones today--we passed 10,000 members!

On average, this site gets 12,000 visitors and 25,000 page views a day, or 300,000 visitors and 700,000 page views a month. The biggest country by far is the US, but even that is only a third of our traffic. The rest of the top ten is below, but note that the rest of the world beyond that accounts for another third of the traffic. The amateur UAV world is a very long tail:

We continue to gain 1,000 member every 2.7 months. After we instituted some tough spammer-control measures at the beginning of the year, it slowed down for a month, but now it's speeding up again. Every one of these members has been reviewed by a moderator; I hope you notice the near-total absence of spam as a result. Thanks, moderators!

And thanks to all 10,000 of you---this community was created by the members, and it's a thrill to watch it grow and take new shape each day. And a special thanks to Morli, whose role as head moderator is perhaps one of the most important here, even though it doesn't show up in the code or PCB boards. The key to great community development is great community management, and our growth while keeping the signal/noise ratio high is a tribute to the job Morli is doing.

For a long time I've been wanting to make an ultra minimalist vision / optical flow sensor for the hobbyist and experimentalist community. I've been pursuing this as a small IR&D pet project at Centeye. We're almost there.

The above photo shows one of these sensors next to a millimeter scale. The part count is small- One of our 64x64 custom image sensors, an Atmel ATmega644 processor, several resistors and capacitors, and some lightweight flat optics we developed. Two complete sensors are shown, including with mounted optics (yes it's that thin!). Total mass is about 440mg. The primary interface is via I2C/TWI, which will allow many sensors to be hooked up to a common bus. A secondary connector includes the interface with the ISP for uploading firmware.

We chose to use an ATmega processor since they are loved by hardware hackers and are easy to use. Ideally for a single sensor, one can upload any number of different "application firmwares" to the sensor to make it whatever one wants, limited by just the processor and the base resolution. One firmware will turn it into an optical flow sensor . Another firmware will let it track bright lights. Yet another firmware could turn it into something else. Or someone could write their own firmware, whether by tweaking existing source code (yes I plan to share it) or writing something completely new.

An ATmega644 may not sound like much for image processing- 64kB flash, 4k SRAM, 2k EEPROM, 20MHz max. Neither does a 64x64 array. But the reality is if you are witty you really don't need at lot of resolution or processing power to get some nice results. (We once did an altitude hold demo with just 16 pixels an 1MIPS back in 2001.)

We've already made our first batch of these (about 20) and handed them out to a few close collaborators. Based on feedback we are preparing our second run. The new sensors will be slightly larger and heavier (thicker PCB) but more rigid, and use strictly 0.1" headers for all IO and power (including programming). Mass should still be under a gram.

We also have an even smaller version in the works, shown below with a chip mounted and wire bonded (sorry about the mess). This board uses ATtiny and the 7mm x 8mm board alone weighs about 95mg. I think we can get a whole sensor made for about 120mg, if only I had the time! (Maybe some brave person here would like to take a stab at programming it???)

Just wanted to inform you all that I have sucessfully modded and flown William Premerlani's UDB2 board (red board) with the invensys gryo board designed by Russell Duffy. The AP / stab code was MatrixPilot r466 and the planes were a Fun Jet and an Easystar clone (higher wingloading and with ailerons).

Our buddy Nathan Siedle, the CEO of Sparkfun, has started a great series of posts documenting his high altitude baloon project. It starts here, but the really cool geek-out over sensors and wireless starts here.

Here's the custom PCB:

Sensors include:

• GPS
• Accelerometers
• Pressure
• Temperature
• Humidity
• Ambient light
• Battery level

Plus long-range wireless modems and onboard datalogging.

Sadly, the wireless link was lost and the balloon and the electronics are somewhere in the plains of Eastern Coloradao.

From Wired.com (which I don't run, btw--I just run the sister division, Wired Magazine), a good article explaining why the apparently underpowered Arduino has proven more successful than more powerful computing boards, such as the Beagle Board. Excerpt:

"The Arduino community is at least 100,000 users strong. But it is not alone.

Other open source projects like the BeagleBoard, which is shepherded by Texas Instruments, are trying to win Arduino fans over.

The Beagleboard is a low-power, single-board computer, whose latest version is based on the same 1-GHz ARM Cortex A8 processor that drives the most sophisticated smartphones today. That gives it far more processing power than the Arduino. Yet the BeagleBoard hasn’t hit the same kind of chord with hardware hackers that the Arduino has.

“The BeagleBoard is not for a novice,” says Phil Torrone, senior editor at Make magazine and creative director at Adafruit, a company that sells DIY electronics and kits. “With an Arduino, you can get an LED light blinking in minutes.”

Five reasons are given for Arduino's success:

• Starter projects
• Costs and durability
• A thriving community
• Maturity is key
• Simple is attractive

Read the whole thing here.

PIANFORMOSA 26 6 2010 promo from Tittap123 on Vimeo.

Thank to Mario for this beautiful day and Tittap for his Great Video :)

for more info .. power point and for meet the people in the video meet us 8 July at 22.00 PM (ROME TIME) in our first skype conference add VirtualRobotix to your skype firends http://www.virtualrobotix.com ;

Roberto

We don't cover military drones here, but I thought I'd make an exception for this excellent LA Times article, which shows that the pros have as much trouble with their UAVs as we amateurs do!

Some highlights:

"Thirty-eight Predator and Reaper drones have crashed during combat missions in Afghanistan and Iraq, and nine more during training on bases in the U.S. — with each crash costing between $3.7 million and $5 million. Altogether, the Air Force says there have been 79 drone accidents costing at least $1 million each."

...

"At least 38 drones are in flight over Afghanistan and Iraq at any given time."

...

"At least one drone crashed because it had no fuel gauge, and the aircraft ran out of fuel. In another crash, investigators cited a design flaw: The "kill engine" switch was located next to the switch to lower the landing gear, and a ground-based pilot confused the two."

...

""These airplanes are flying 20,000 hours a month, OK?" said retired Rear Adm. Thomas J. Cassidy Jr., president of the aircraft systems group at General Atomics Aeronautical Systems in San Diego, which makes Predators and Reapers. "That's a lot of flying," Cassidy said. "Some get shot down. Some run into bad weather. Some, people do stupid things with them. Sometimes they just run them out of gas."

...

"On Sept. 13, a pilot inside a ground station in Nevada lost video and data links to a Reaper over Afghanistan. As it was about to exit Afghan airspace and crash, an F-15 pilot was ordered to shoot it down and ground troops recovered the wreckage to keep top-secret technology out of insurgents' hands."

...

"After a Predator crashed during a landing at Kandahar air base in March 2007, investigators faulted the Predator system for a "lack of visual cues" to help pilots understand the position of a plane flying half a world away. The pilot in Nevada misjudged the drone's altitude, the investigative report said.

The Predator that ran out of fuel over Iraq had a leak, but there was no gauge to warn the pilot, an Air Force crash researcher said. And a pilot trainee at Creech Air Force Base in Nevada crashed a Predator by hitting the "kill engine" switch instead of the adjacent landing gear switch, according to an investigative report.

Some ground control stations, where pilots and camera operators sit, still have 1990s-era text-based computer systems. Pilots have to type function and control commands rather than clicking on icons.

"There's a control delay between typing something and having it actually happen on the airplane," said Gregg Montijo, a contractor who trains drone crews. "When the heat is on, sometimes guys will type something in, then type it again real quickly. They'll confuse the computer and get the wrong display and get into a vicious cycle."

Here's a nicely priced Hitec 2.4 GHz transmitter with built-in telemetry. Perhaps an upgrade for our groundstation?

For now, the sensor is only for battery condition but the plan is to have more sensors. Perhaps we can use the data channel as-is..

link