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Posted by Genesis Factor on October 1, 2007 at 8:00am

Helicopter- Why the EFlite Blade CX

It is small, light weight, modifiable, and parts are cheap and readily available at the local hobby shopor on eBay. The Blade CX is consideredan indoor outdoor, meaning I can test the helicopter indoors during inclementweather, and a Ready To Fly (RTF) helicopter, so limited set up isnecessary. It is also a twin rotordesign with counter spinning blades, meaning there is little learning curvewhen flying. This will make it mucheasier to program for as the helicopter should be a stable startingplatform. Also I already have one.

I picked the CX over the CX2 model as the CX uses standard FM signals over the CX2’s 2.4 GHz. This means that even though I lose theability to jump frequencies, the helicopter’s operation will not be affect by,or affect nearby 2.4 GHz systems, such as wireless LANs, Bluetooth, or othercommon devices.

The blade CX has a 300ft out door unobstructed range. This can be enhancedwith a more powerful radio, but 300ft is plenty for demonstration purposes.

Wireless Camera- Why the ZT-811T

This is a small camera with a 2.4ghz/900mhz frequency. I would ratherthe 900mhz, due to wifi interference and future implementations, however i doneed to use it as 900mhz needs “line of sight” to work while the 2.4 ghz seemsto just have reduced quality and range. Since this camera is needed for seeing out of the “cockpit”, just incaseyou need to navigate treacherous airspace with precision, or you lose sight ofthe copter and just want to know what its doing and where its going, this isvery necessary. The near VGA qualitymeans that the image comes out large and clear. Also, as it is a pinholecamera, focusing won’t be a problem unless you are viewing it in a low lightsituation. Specs are below

· Iris Automatic

· Exposure Automatic

· Focus Adjustable 30 mm to Infinity

· Validity Pixel: NTSC - 510x492

· Resolution 380 Lines

· Horizontal Viewing Angle 52 Degree

· Effective Range 300-1000ft

· Voltage 9 to 12 volt DC (receiver)/6-9 volt DC(camera)

· Power Consumption 200 mWatt (camera) 200mWatt (receiver)

· Current Consumption 200 mA (camera) 500 mA(receiver)

· System NTSC ONLY

· Operation Duration of Camera 8 hours on 9 voltDuracell or Energizer

· Dimensions 20mm x 20mm x 20mm

· Video Output Through RCA Video Cable

· Minimum illumination 3 Lux

Microcontroller board.for output

This is still under evaluation with my friend who is an EE. Looks like I’ll have to besoldering. At the moment, we’ve jumpedform analog outputs to digtal outputs with a digital pot for each joystickcontrol.

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Independent Study Proposal- what started it all

Posted by Genesis Factor on September 25, 2007 at 10:30pm

Independent Study Proposal

Primary Goal

Build an interface to control an RC helicopter via a computer, effectively creating a UAV

Time Line

Ø By October 1st- have research completed.

Ø By mid October- have all the materials gathered/enroute as needed

Ø By November 1st- have the model mechanically assembled

Ø By Mid November- have the basic computer controls operational

Ø By December 1st- have computer controls tweaked

Ø By Last day of Class, have research project written up and we present the final model

Meeting

Professor Samaras and I will meet bi weekly to discuss the project. During this time, concerns, issues, help, guidance, and expertise will be exchanged towards completing whichever goals we are at.

Grading will be based on these criteria

  • Research (10)
  • Written report (10)
  • Completion of the mechanical side (20)
  • Completion of the electrical side (20)
  • Completion of the computer programming side (20)
  • Smoothness of controls (scale of 1-5)
  • Ergonomics (ease of controls (scale of 1-5)
  • Ability to stick to agenda without falling too far behind (1-5)
  • Staying on task (1-5)

Secondary Goal

Have the helicopter return its global position and a visual feed of its whereabouts. Also, the vehicle will be able to fly about in space after inputting where on a map you want it to go and how high you want it to go.

Tertiary Goal*

Have the helicopter be able to monitor positions, track objects, and post alerts and react to different stimuli, and attempt to find home when it sense that any of the above feeds are too low.

*As the tertiary goal will have computer vision components, if the decision is made to continue the project into another semester to incorporate such goals, in other words, the secondary goal Must be fulfilled, then credit for the computer vision class will be given at the end of the following semester

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Australian UAV Competition This Week (Sep 24-27 '07)

Posted by paul hubner on September 25, 2007 at 8:43am
http://www.uavoutbackchallenge.com.au/

A few months back, this got some play on the RCGroups.com UAV websaite, but I have not heard much since the initial conversations. Is anyone planning a visit or in the area to report? As of today, only four teams qualified for the outback challenge and three highschool teams for the target drop event.

News Update:
ARCAA is the sponsoring organization. They have some news links about the challenge here:
http://www.arcaa.aero/news.php With the way the US Dollar has dropped, the prize money just keeps getting more valuable :-)



Paul
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3D Robotics

Testing two GPS loggers: thumbs up and thumbs down

Posted by Chris Anderson on September 24, 2007 at 12:16pm
If you're planning to turn your UAVs (or just R/C planes) into aerial mapping machines, you're going to want a GPS data logger. What they do is give position information that you can match with each of your shots, so you can properly align them into a mosaic and place it on Google Maps. Companies such as Pict'Earth can take a GPS log file and a zip file of a few hundred shots and turn them into a beautiful orthorectified Google Earth overlay like this.

I've used two GPS loggers: the i-Blue 747 Bluetooth device from Transytems, and the Trackstick II. The first I can recommend highly; the second I can't recommend at all. Here are the facts so you can make up your own mind.

1) The i-Blue 747 can be found for $70 at Amazon. It's got 16MB of memory, tracks 32 satellites and has Bluetooth so you can use it for real-time telemetry and even have it drive an autopilot. It comes with rechargeable lithium batteries and is really small (approx 2.9" x 1.75" x 0.75"). The software does all the basics, including letting you download a saved GPS session to Google Earth or a CSV text file and let you see satellite positions and current reading in real time.

[Note: the software communicates with the device via a virtual Com port, handled by a driver. It can be a little tricky to figure out which Com port, however, so I suggest you go to your Windows device manager and see which port was assigned to the device and set the software to use that. On one of my machines it was port 5; on the other it was port 10; it depends on how many other drivers you've already loaded.)

It also saves GPS positions once per second, which is important when you're trying to match it with pictures you're taking at least that fast. In our testing, it aquired a satellite lock in less than minute and was rock-solid in keeping it, even when we just tossed the device randomly into an aircraft's instrument bay, buried under other electronics and bathed with other radio emissions. Basically, we've used this devices on dozens of flights, UAV and otherwise, and its performance has been top-notch.

2) The Trackstick II costs nearly $150 at Amazon. It only has 1MB of memory and only tracks 12 satellites. No Bluetooth, so it's just a logger with no real-time function. It requires AAA batteries, and is long and rectangular, about twice the total size of the i-Blue (4.25" x 1.25" x 0.9"). It has a built-in USB jack, so you can plug it straight into your PC (the i-Blue requires a standard USB cable). The software does essentially the same thing as the i-Blue's.

In testing, three serious problems cropped up with the Trackstick (aside from it being expensive, big, and badly underfeatured):
  1. It only records a GPS record every 15 seconds in low-power mode and every 5 seconds in high-power mode. Even at the highest, battery-draining settings, that's way too slow for aerial mapping.
  2. It takes forever to get a satellite lock. The first time, it took more than half an hour and subsequently it took more than three minutes.
  3. Keeping that satellite lock is a struggle, too. By having a terrible GPS chip that only sees 12 satellites, the Trackstick II suffers from frequent drop-outs and glitchy datapoints. We found it essentially unusable.
Basically, I can't understand why the Trackstick is even sold. It does nothing that the i-Blue747 doesn't do at half the price, and doesn't do other important things like Bluetooth, 1-second GPS sampling, and having a useful amount of memory. I'm sorry I bought it--avoid.
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3D Robotics

Red tape grounds military UAVs, too

Posted by Chris Anderson on September 22, 2007 at 9:10am
Noah Schachtman at Wired's Danger Room blog reports from his recent trip to Iraq. Turns out that we're not the only ones having trouble with airspace regulators:

"The Defense Department's unmanned air force has grown exponentially; there are now more than 3200 mil-drones in the fleet, up from about 200 in 2002. But after spending some time in Iraq, I'm starting to get the feeling that a lot of those robo-planes are sitting on the shelves, barely used.

Here's why. The military's big unmanned aerial vehicles (UAVs) are controlled by colonels and generals. The local commanders on the ground basically have no say where the things fly. For example, a company commander, recently returned from Anbar province, sa id his area got a grand total of eight minutes of coverage from the Predator spy drone per day.

But wait, you say. The vast majority of America's UAVs are little, hand-launched drones, like the four-and-a-half pound Ravens and the five-pound Dragon Eyes. The local captain has control over those, right? Well, theoretically, yeah.

But there are so many bureaucratic hoops to jump through to get those tiny UAVs in the air that many captains have stopped bothering to try. Air clearance is the hoops that comes up most. Although the drones are small, they can get up pretty high -- 1000 feet, or more. Which means there's a concern about the UAVs getting tangled up with helicopters. Setting aside space for the drones can take 24 to 48 hours -- and insurgents don't usually stay in one place that long.

A few weeks ago in Anbar, I spoke to local Marine commander who had basically given up on using his Dragon Eye, for this reason. The same thing happened in Tarmiyah, north of Baghdad, where Captain Pat Roddy told me, "the Raven? Never fly it." Which is particularly frustrating. Because Roddy regularly gets airspace for himself, to fire mortars. But his higher-ups won't let him launch his drone during that time, because the computer program that tracks airspace says its a no-aircraft zone. Roddy has been told that he can make an emergency switch from mortar to Raven airspace -- and it'll only take an hour to make the switch in the computer. But he can only do so if his troops are in a firefight. And firefights in Iraq almost never take more than a few minutes. An hour later, the Raven is all-but-useless."

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Moderator

Just playing around

Posted by Gary Mortimer on September 20, 2007 at 11:44am
Work has actively kept me away from doing stuff I would really like to get into.

The main problem being a move to cover for somebody that is ill to Scotland. Initially for two weeks but thats turned into 2 months. The point, all my gear was down south.

I went and picked it all up last week so can start again.

The weather will be the problem now!!

Anyhow I will post a video from a Pentax Optio T10, taken from a hill, East Lomand just to the north of Edinburgh.

Not earth shattering as I had the camera in completly the wrong position. Anytime I taped it in a place I thought would give great pictures the drag became too much for the slope soarer.

I thought that the CoPilot CPD4 might level the wings nicely in the rough cliff lift but instead it kept the wings rocking too much. Still nothing ventured.

This evening I will put the Copilot and RCAP3 alt hold in a trainer airframe I have and weather permitting send it off into the morning sky.

G

Once those two work well I will add the RCAP and waypoint sequencer.


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3D Robotics

Turning an EasyStar into a proper camera platform

Posted by Chris Anderson on September 17, 2007 at 9:37pm
Multiplex EasyStars are one of the most popular aerial photography aircraft for a good reason: they're cheap, stable, tough and easy to modify. In an earlier post, I described how to upgrade one for better performance. In this post, I'll show you how to install a camera for great Google Earth mapping, producing high-resolution, stitch-ready imagery like this.

[UPDATE: some of you have wondered why I'd want to use this foam glider when we have several other excellent UAVs and aerial photography aircraft, some of them including such niceties as stabilized camera mounts. The answer is that often there's no runway or clear landing area where we're working. The aircraft with fancy payload platforms hanging beneath them are designed to land on a smooth surface, and crunching into a hillside will damage the camera along with its mounting equipment and often the plane itself. The EasyStar, by contrast, is hand launched and can land anywhere, and the camera is protected inside its soft foam body. And if it hits anything or anybody, it won't do any damage.]

The secret to getting shots that you can mosaic into a large-area map is to take a lot of them, as quickly and at as high resolution as possible. That usually means a digital camera shooting straight down in continuous mode (which takes a picture every half-second or so as long as the shutter button is held down), with a high shutter speed to avoid motion blur. For various reasons, the usual ways to trigger a camera remotely--IR shutter triggers, USB connections, or stop-motion settings--don't work with continuous mode. So the only way to do it is to hack into the camera and find the circuitry that triggers the shutter (which is too scary for me) or to have a servo manually push down on the shutter button. Here's how to do the latter:

The first thing is to carve a bit of foam out of the sides of the EasyStar's instrument bay to fit a standard pocket digicam (I'm using a 10 megapixel Pentax Optio A30). A big kitchen knife will do it. Then carve a hole in the bottom where the lens will go when it's extended. Finally, because you've weakened the body by carving away that foam, you'll want to epoxy in two reinforcing strips (I used spruce spars I found at the hardware store), which will also serve as the mounting rails for the camera.

When you're done it will look like this, with a little extra carving at front and back so you can place the camera properly (I carved a bit too much foam from the left side of the plane, so I put in a thin plywood sheet to reinforce that area):


The next thing is to epoxy in the servo (the blue thing in the picture above) that's going to depress the shutter button. This is simply a matter of carving out a servo-sized hole in the side of body, after measuring carefully where the camera's shutter button falls when it's on those rails. Make sure you've cut off all non-essential servo arms and re-seated the arm so it it's fully pushing down the camera button when you turn on the channel 5 switch on your transmitter before gluing it in. From the side, that looks like this:


That's pretty much it. When the camera's in, it looks like this:

And from the bottom, it looks like this:

You're ready to go! Just remember to rubber-band everything in tightly so it doesn't shift in flight, turn off the auto power-off on the camera, set it to a relatively high ISO setting (800 works for me) to avoid motion blur and put in a high-capacity memory card (at least 2 gig). Once the plane's in the air and flying smoothly at around 200 feet you're ready to toggle the channel 5 switch and take strips of shots to later composite into a full-area map. Or just put in an autopilot and turn the EasyStar into a proper UAV and can follow those strip tracks itself.
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Burning Man '08 FlyBy

Posted by Ivan Kirigin on September 14, 2007 at 11:00am
Lots of my friends and family go to BurningMan yearly. I've never been, but I do enjoy their flickr streams.

I found a link to a very high resolution satellite image of the Burning Man site [8698 x 8735]. But compared to what you could get from a flyover, the resolution is small.


Daily flyovers uploaded to a server which used a GoogleMaps API would be lovely.

Ideally, images would be sent over a cell-network connection on the UAV directly to a server, for live update. Justin.tv meets DIYdrones meets massive hippy/art gatherings.

[UPDATE] Even without cell network coverage, the system could be live with an 802.11 connection to a ground unit, networked with a Satellite Internet base station.
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3D Robotics

Warning: Spread Spectrum R/C and 2.4 GhZ video downlinks don't mix!

Posted by Chris Anderson on September 11, 2007 at 4:02pm

In a comment on a thread at right, David Albert makes an important point about frequency clashes between spread specturm radios and 2.4 Ghz video downlink systems, such as the RangeVideo and Black Widow AV setups that we use. If you haven't been following the chatter on aerial photography newsgroups, you might have missed this (as I did). This info may save your plane!

  • "Having a 2.4Ghz Tx right next to a 2.4Ghz Rx is a bad idea. Regardless if it is Spektrum, Futaba, or Xtreme Power Systems. Once you get a certain distance, the video TX will swamp (overload) your Rx. Imagine looking into a bright spotlight and trying to see a candle in the distance. Even if the candle is changing colors (changing frequencies, ie spread spectrum) it is just a matter of time and distance before you can no longer see the candle. Check out ezonemag.com there are many many threads on this under the UAV forum and FPV forum on this. That is the reason why people with 2.4Ghz RC systems are moving to 900Mhz video or keeping 2.4Ghz video and using plain old 50Mhz or 72Mhz RC Transmitters."
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3D Robotics

Is this the miracle chipset that's going to make DIY drones easy?

Posted by Chris Anderson on September 10, 2007 at 10:38pm
Analog Devices is about to start selling a very cool-looking device: a small box that combines three-axis gyros with three-axis accelerometers, along with an embedded processor to massage all that data and deal with calibration and drift issues. Called the ADIS16355, it will retail for about $300, which isn't cheap, but when you consider what it would cost you in time and money to duplicate that functionality, it seems more than worth it.

Not sure what accelerometers and gyros are good for? They're what's needed to build an Intertial Measurement Unit (IMU), which is the core of a proper autopilot. Tom Pycke has a great series of blog posts that explain all this in lay terms (at least at the beginning--then it gets into math):

If you're contemplating building your own autopilot or taking on one of the open-source ones, these posts are the right place to begin.

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3D Robotics

Modding the Nitro Models 4-channel Predator

Posted by Chris Anderson on September 10, 2007 at 11:26am
As I mentioned, I totaled the first Predator UAV, due to the combination of an underpowered motor and the marginal controllability of that design's V-tail-only steering. I spent last weekend replacing it with a different Nitro Models Predator, which has ailerons. Unfortunately, that model is currently out of stock at Nitro Models (I had a kit I'd bought some months ago), but on the off chance that it comes back in stock and someone out there wants to build it right, here are some tips:

  • For the ailerons, you'll need micro servos like the Futaba S3114s. When you're threading the servo extension cables through the wing, wrap the connectors with tape and taper the wrapping into the wire, to avoid connector edges that will catch on wing bulkheads.
  • You definitely want steerable landing gear. There are a lot of good tips on how to do that in this thread. One of the things that stumped people was how to use servo mixing for the V-tail and still use the rudder to steer the nose gear. The answer is to use a VeeTail hardware mixer, with a Y-connector from the receiver going to the nose gear servo and the VeeTail input. The VeeTail board is also compatible with the UNAV PicoPilot autopilot, which we'll be using later.
  • I used a Hacker A30-28S motor with an 8x6 pusher prop. I had to use 1/2" spacers to get it far enough back to clear the fiberglass rear cover. And even then I needed another 1/4" nut on the prop shaft to get the prop far enough back to clear the cover. (BTW, if you use the Hacker you'll have to trim away an eighth of an inch around the open in the back of the fiberglass cover to clear the prop mount.
  • I made the wings removable. This involved putting little hooks in the side of each wing and drilling a corresponding hole in the fuselage on each side. A short rubber band, threaded through the fuselage with a paper-clip hook, keeps the two wing halves from falling off.
  • I put two spruce rails on the bottom of the plane, just ahead of the landing gear (ie, right on the center of gravity) , and put screws sticking out them at the front and back sides of each. This will serve as our payload attachment point, and the screws sticking out are for rubber bands. It fits our stabilized camera mount beautifully.
  • It remains to be seen how well the UNAV PicoPilot flies this plane. UNAV warns against planes with ailerons and little dihedral, which is the case here. Until I test it in autonomous mode, consider this just a very cool looking R/C aerial photography plane.
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MY UAV project

Posted by Ahmad Usman on September 8, 2007 at 8:39pm

Hi everyone, I am running a student satellite project in Pakistan. http://www.informationvision.net . Now I want to start a student UAV project. My aim is to develop an agriculture UAV which can monitor SALIN water in Rahim Yar Khan which is major issue for the farmers in the region. Can anyone help me with documentation for the projeect.

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3D Robotics

Using Pict'Earth for image processing

Posted by Chris Anderson on September 7, 2007 at 2:59pm
Now that we've got several UAVs running well, it's time to show what they're good for. Aerial photography is fun, but it's not really useful unless you can cover large areas and integrate the imagery into Google Earth. I've been stitching together images optically and superimposing them on Google Earth, but it takes forever, still requires a lot of hand tweaking and isn't really well integrated into Earth. What I needed was an automated solution, which is why I was so pleased to see the service Pict'Earth recently announced.

The image at right is one that they processed for me. I uploaded a bunch of photos taken by a camera in continuous shooting mode (it was a Canon SD650 shooting twice a second) and a GPS record of the same flight (we just put a GPS data logger onboard and downloaded the data later). The Pict'Earth software synchronizes the time stamps on the photos with the GPS records and then outputs a KML file that automatically mosaics all the photos into Google Earth. It's really quite cool.

The example shown here is a screen shot of one run over the Alameda Naval Air Station. Here's the KML file--download it and it should load automaticaly into Earth so you can see how it all works.

The Pict'Earth team is still developing the software to do this on a large scale and is working out pricing plans. They're updating their website and should have that all available there soon. In the meantime you can contact them directly here. You can also follow their progress on their Ning community site, which is well worth visiting.
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3D Robotics

How to mod a Multiplex EasyStar

Posted by Chris Anderson on August 31, 2007 at 6:30pm

I was reminded by the Pict'Earth guys last weekend that one of the best all-purpose planes for carrying cameras, GPS recorders and any other sort of equipment you want to test is the Multiplex EasyStar, a virtually unbreakable powered glider. Because it's made of elastopore foam you can carve out the equipment compartment to carry pretty much anything you want, and the same foam protects everything in case of a "hard landing".

EasyStars are available for $54 without the radio equipment. This post is just a quickie to show you what else you'll need top make them good UAV platforms.

Although the kit comes with a brushed motor, I suggest you upgrade to a brushless so you can carry heavier loads with ease. This motor is a perfect fit and has power to spare. I matched it with this ESC. As always, you'll want Li-Ion batteries if you can afford them. An 11.1v, 2200 mAh pack will allow you to fly for more than half an hour under power. A 6x4 prop fits perfectly

For a radio, almost anything with six channels or more will do. The EasyStar has compartments pre-cut for servos; the HITec HS81s fit them best.

Finally, here's an important point. With the more powerful brushless motor, you'll find that rudder is really too small to be effective. You need to make it bigger to increase its "authority", which both helps in more extreme moves and at slow speed. The easiest way is to glue or double-sided-tape two business cards to the rudder. Here's a picture of one such mod (I didn't bother to trim mine as neatly as this guy did):

Once you've done all that you can shove all manners of cameras and such in the equipment area. If you don't want to carve holes in the bottom, you can always just bolt a camera to a bit of wood and strap it to the top, like this.

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Imagery is everything!

Posted by Leon Herbert on August 30, 2007 at 2:06pm
I have joined this group in the hopes that I will be able to learn more about UAVs. I would like to be able to utilize them in search and rescue. Often we have no good imagery or even maps of areas that we have searches for lost people. It would be great if we could get imagery from a UAV and make it available to rescue personel to assist in search efforts.
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What model remote control extend range to 5 miles

Posted by alison on August 29, 2007 at 7:50am

me and my college friends built small Glider UAV with real time video camera transmission. but my remote control works only visual range. We intend to extend the uav range to 5 miles with the help of Autopilat and ground control software. can anyone help me to chose the extended range remote control. (what model RC and where can i buy this things by online or anywhere in europe.)

SOOn i will post my entire UAV project in website.

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3D Robotics

UAV fly-in report

Posted by Chris Anderson on August 28, 2007 at 7:40am
We had our amateur UAV fly-in (the world's first?) on Saturday at the Alameda Naval Air Station. Along with my own 4 UAV's, Adam Williams brought his fully-autonomous-in-training heli, the Pict'Earth team was there with their Nokia N80-carrying Easystars, RCAPA's Patrick Egen brought a nifty camera-carrying slowstik, and we had a handful of other observers, along with the PBS film crew.

Since this was done mostly for the cameras (which can't tell the difference between autonomous and RC flight), we didn't really push the UAV envelope very far. I put the Lego UAV in autonomous mode for a minute, and I saw Adam with his hands off the controller for a while as the heli maintained position beautifully. I had the PicoPilot UAV there, but we didn't have time to fly it. And on a sad note, I totalled the Predator, which was an accident waiting to happen due to the terrible flying characteristics of the V-tail-only version. (I've now migrated the electronics to the second Predator, which has ailerons and should be much more controllable).

Most of the day was spent on optics and mapping of various sorts. The PictEarth guys showed their fantastic software that generates KML files in real time, with just a cellphone and a Bluetooth GPS sensor. Here's an example of what they demonstrated (you need Google Earth to display this).


I was testing my auto-stabilized camera mount and GPS tracker, and I must say they did better than expected. Here's some examples:

A GPS track of one test flight:

Here's the photo output of one pass mosaiced by PTGui. The camera was a Canon Digital Elph 630 (6 megapixel) at ISO 800 and continuous shooting (about twice a second). The composite below represents about fifty individual photographs.


And here's the same mosaic composited against the relevant spot on Google Earth (sorry about the white part; I need to figure out how to hide that):

Not bad, huh?


Finally, here's an example of the quality we get from each shot (click for a full-rez version). We're not quite at license plate-reading quality, but that's not bad for a six megapixel. When we swap in a ten megapixel I think we'll be there--at this point the airframe, stabilization system and camera mounts work great and it's simply a matter of using the best camera for the job.

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