Blogs

BaroneOSD is a PAL video overlay impression WITHOUT additional hardware required (NO LM1881 Sync generator).

Use only 3 pin:

D1 (USART TX) used to pump pixel in the video connected with a 330Ohm resistor to D6

D6 (AIN0) Video in/out, connect here you camera or radio TX.

D7 (AIN1) 0.3V Voltage reference (you can use a partitor resistor)

Jason Short and I had great day of testing and improving code (and putting in a pretty good T3 contest time!). Once again we were at the RC club in Point Richmond, across the Bay from San Francisco. Jason was just back from a skiing vacation where he tangled with another snowboard to the tune of 17 stitches on his ankle (I saw them: ouch) but fortunately UAV development doesn't require a lot of running.

You can see what flight testing looks like above. I fly, he watches the telemetry and then makes changes in the code for me to test.

Here's the rundown of the day's progress. You should see all this reflected in the code in the repository in a day or so:

The Good:

--Navigation is now locked in pretty well. Straight lines to waypoints (no more snaking) and pretty tight turns between them.

--Manual throttle control now works in autopilot mode! Just like you can "nudge" the plane's direction with RC controls while it's flying autonomously, you can now speed it up or down. Excellent for finding the best speed for T3 runs!

--The funky thing with one of my Futaba FASST receivers working and the other not was solved. Turns out that one of them outputs the PWM on all channels in serial, and the other in parallel. Who knew? Anyway, ArduPilot can handle either. If your radio does something weird like only letting you fly left, not right, edit this line in the config file:

//3-2

#define RADIO_TYPE 0 // 0 = sequential PWM pulses(Fasst, Spektrums), 1 = simultaneous PWM pulses (Corona RP8D1)

--We flew the FunJet in RC mode (although it has an ArduPilot, we haven't set up elevon mixing yet). Amazing performance: fast, rock solid and incredibly maneuverable. Once we get it dialed in with the AP, we're going to be looking at sub 10 second Sparkfun runs ;-)

The Bad:

--We still don't have altitude hold working right. We finally got it to display the right altitude in the ground station, but for some reason it's not holding. Jason thinks this is just a matter of tweaking throttle and pitch gains, but for now I had to trim the pitch down manually for the T3 trial runs just to ensure the plane didn't get too high during the autonomous portion.

--We're getting different results with different sensors. I'm flying with FMA sensors, and Jason was flying with DIY Drones sensors. The calibration routines should mean that as long as you've got a matched pair it shouldn't matter where they come from. But for some reason it still does, and different sources require different gains in the code. We'll figure out a way to make that go away...

The Stupid:

--I almost crashed one time by launching with stabilization accidentally on, but not yet calibrated (it takes a few second to calibrate in the air). Also we found that if you happen to power on in stabilization mode, it messes up your waypoint settings (for some reason it thought it was starting on waypoint 7), so for now just don't do it until we can find and fix that bug.

--I also almost crashed launching downwind. In my defense, the wind shifted direction. But still!

--I nuked another Xbee by powering on with the signal line attached. I can rescue it, of course, but I CAN'T WAIT for ArduPilot Mega to make this problem go away with the dedicated serial lines.

Variable Pitch Quad Rotor - M/UAV

DIY project ranging from a 600cc 120HP etec Ski-Doo engine, UltraSport 254 tail rotors, extruded aluminum blades from Vortech, aluminum / steel tube structural components, and a carbon fiber reinforced polymer monocoque frame.

From a Der Spiegel UAV photo gallery. Note the over-the-top caption. What is this toy plane? It looks like a Hobbyzone Phantom!

I've been fascinated by optical flow ever since I learned that you can do some pretty good navigation work with the chip taken from an old optical mouse. I think this is probably going to be one of the methods we use to take Blimpduino navigation to the next level (it's ideal for any unknown environment, as well as GPS-denied ones). As the picture above suggests, optical flow is the method that many animals, especially insects, use to navigate in complex space.

Here's a writeup from Hizook about the latest research in the field. The authors describe the advantages of this technique:

"The main benefit of this method is that the information about the optics and scene depth is wrapped into a model that is easily learned from video from the robot. No calibration grids or complicated lens distortion models are required! The primary limitation from a practical standpoint is the assumption of constant scene depth, which would break down if, for example, the robot turned to directly face a very close wall, departed from the ground plane, or moved from a narrow corridor into a large open area. "

Here's a video that shows how it works:

CVPR 2009 from Richard Roberts on Vimeo.

[Fly image at the top from the Max Planck Society]

Entries for the current T3 contest (virtual Sparkfun competition) are due by midnight PST on Sunday, so this is your last weekend to get a flight in. The current leading time is 25.7 seconds by Brian Wolfe. Here's his track:

Jason Short and I will be flying the pattern tomorrow as we test some new code. We're just using beater EasyStars, so we won't win, but the point is just to enter. Get out there and try the course--it's the easiest one we've done!

Skywalker is now in a new version made of EPO foam. Much stronger foam.

Length: 1180mm
Wingspan: 1680mm
Wing Area¡G35.5dm2
Wing Loading¡G36.6

Recommendation
4 x 9g Servo
3S1P 11.1V 2200mAH-5000mAH
Motor: 2215-1200KV or 2815-900KV
Propeller: APC-9045E 9060E

I think this platform could be the replacement for the smaller Easystar if it's possible. What do you think?

Skywalker is now in stock! This is not the EPS foam, this is the new EPO version - much stronger foam.

See more on this Skywalker FPV UAV platform.

We're always looking for practical applications of what we do. Here's one from from Makezine:

"As you folks know--all too well, I'm sure--it is extremely difficult to collect blood from a wild whale without injuring or killing it in the process. However, and as even a child can tell you, the next best thing to live whale blood is live whale snot. Turns out it spews from their blowholes when they exhale, so the process is really very simple:

1. Find whale.
2. Hold petri dish over blowhole to intercept spout.
3. Return to lab, enjoy sample.

Step 2 is actually the hard part. And although your first instinct may be to just jump in your rowboat, paddle out to a whale pod, lean way out over the side with your sample container, and wait, that's actually not as safe as it might sound. Each year, untold millions of scientists die attempting this maneuver. Their sun-bleached bones litter beaches all along the Pacific coast.

Enter Dr. Karina Acevedo-Whitehouse, of the Zoological Society of London. Her recent paper in Animal Conservation(abstract), irresistibly entitled "A novel non-invasive tool for disease surveillance of free-ranging whales and its relevance to conservation programs," introduces the ground-breaking methodology of strapping a petri dish to a toy RC helicopter and flying it into the spout. This landmark work stands not only to revolutionize our understanding of whale disease, but to save countless lives, and establishes Dr. Acevedo-Whitehouse as a serious contender for this year's (Ig) Nobel "Prize."

[via The Thoughtful Animal]

http://www.fpvhobby.com/25-us-army-fpv-airplane.html

Or their other one

Interesting site

From POPSCI the new wings for drone types.

http://www.popsci.com/technology/article/2010-03/new-era-military-aviation-gets-new-set-wings