|Jul 28, 2011, 01:13 AM|
The Dehogaflier: Skywalker with FLIR thermal camera.
We finally flew our first thermal camera flight yesterday afternoon. About 10 seconds after launch my co pilot looked at the screen and said something like, "We now have our very own predator drone"
It isn't that good, but it is pretty awesome. I've posted about our plans here in a few places but I figured now that I'm mostly finished I'd start a thread showing the build and some sample video from flights etc.
First some background info:
I'm an EE who does Electronic Warfare for a living. This gives me access to some neat toys. I'm also crazy
My family owns rice farms and we have problems with feral hogs causing thousands of dollars of damage. It is so bad that my brother pays me to go out and patrol at night to keep the damage to a minimum.
You can see some AP shots of the damage here.
Hunting big angry pigs in rice that is as tall as your belly button is HARD. Seeing them at anything other than 10 feet away is nearly impossible, you have to walk, listen, stalk, and kill. Then chase the survivors for hours. Sometimes you could waste all night looking in the wrong places or maybe the pigs decided to not come out at all.
This year I decided to work smarter instead of harder. With our own little UAV up there I could spend a lot less time chasing pigs that might not even be around.
Thus the Dehogaflier is born.
Here are the current specs:
Skywalker 168cm V2
Moxie 980Kv Motor
Turnigy Plush 80 Amp ESC
RVOSD Gen4 Board upgraded to Gen5 IMU
Dragonlink for control Rx/Tx
900Mhz 500mW Video
I use a 3S for Video etc, 4S for motor (go away ssander!)
More to come...
|Jul 28, 2011, 01:14 AM|
The only major bit of rework I had to do was a tilt mount for the camera. Considering the price tag for this thing we didn't want to mount it right on the nose without any kind of protection. We had to be able to look down as well. In fact we plan on looking down almost all the time. So I decided to mount it inside the nose with a slot cut to see out of.
The camera and mount and control rods made it a little too big for the Skywalker nose so I made my own out of balsa. Then I chopped most of the Skywalker's nose off and glued the wooden frame in place.
After this I filled the gap with expanding foam and trimmed it back to shape. The expanding foam is a little more spongy and crumbly than EPP so I will probably glass over it later. I wish I had mounted it an inch or two further out. I may try again and do pan and tilt on my other skywalker frame.
More on the camera.
We went with a Tau 320 because the PathFindIR supposedly didn't have decent adaptive auto gains and other settings like the Tau's have. Also the Taus are way lighter and smaller. We also couldn't afford the Tau 640 and I wasn't sure how well the extra resolution would make it past the video Tx anyway. (anyone know the answer to this?)
The 320 was around $4500, the 640 was around $9000 if I remember correctly.
We did a little pixel size math based on the size of a pig and the desired flying height etc and decided that a 19mm lens was our best bet. A wider view would have me flying too low, a tighter lens would make it hard to land.
So far it looks like I could possibly spot an adult pig at up to 1000ft up if I'm looking directly down on him. At one point during the maiden flight the ship was around 1400ft away LOS and you could still see me sitting by the ground station.
Will type more later... Need to sleep.
|Jul 28, 2011, 01:15 AM|
Here's the video just in case I fall asleep before I get finished typing all the info above....
Test video from ground
Test video from ground vs deer in a bean field
Maiden Thermal Flight
|Jul 28, 2011, 10:01 AM|
The problem is that this is waaaaay out in the country with no city lighting etc. I could probably get it done on a moonlit night but I'm not familiar enough with the low light cameras to know if it would work with starlight only.
|Jul 28, 2011, 12:17 PM|
Joined Dec 2004
Dude that rules! Are you gonna have a spotter in the plane to guide in the hunter on the ground by radio?
|Aug 14, 2011, 03:07 PM|
This is how things have gone so far...
After the first thermal flight posted here we went over to the farm to try and spot for feral hogs. We launched and everything was great except for the camera being tilted up slightly which made me fly tilted down all the time and well... you get the idea. Nothing broke, rice fields make a great cushion.
After that I made some major changes to the airplane. Better Dragonlink antenna setup. Better RVOSD anti vibration mount. And we made a camera mount for the daylight camera so we could quick change between it and the thermal cam.
I did lots of test flights with the daytime camera getting things trimmed and tuned and comfortable. The problem with the thermal camera is that it has a very narrow field of view compared to what we all fly AND it just makes the horizon a nasty blur. So I had to get used to flying with the RVOSD data on screen and trusting it.
We made another trip to the farm Friday and everything wen't ok. Did a daytime flight to survey damage.
Then we did a dusk flight with the thermal. Very stressful. There anything out there but fields and trees and they are all pretty much the same temp! Add the tight field of view and it is very easy to get disoriented. Would be totally impossible without an OSD.
After that we landed, charged the batteries and had a smoke to calm my nerves. We launched again at around 10 pm. My copilot/spotter/communications officer used a spot light to help me take off. We have LED's on the wings and reflective tape so it wasn't too hard.
I found the flying much easier this time, I think the cool of night was helping. There was a decent wind blowing and at one time I was actually flying backwards according to the gps
We spotted a pig on the camera and shortly afterward my camera tilt servo died (stuck looking down!) so using RTH and the spotlight I landed it asap.
We loaded up and converged on the pig's position a few mins with intent to do violence but it turned out to be a little deer taking a nap.
It was an exciting and exhausting night. Flying with that camera is HARD. Later on everyone else went home but I stayed to try and find the pigs the old fashioned way. I ended up falling asleep on the road only to be woken up an hour later by some big giant beast of a pig wallowing in the ditch a few yards from me. He ran away before I could get a shot off.
|Aug 17, 2011, 03:53 PM|
|Aug 17, 2011, 05:45 PM|
Joined Nov 2008
Nice. Like those gunship games!
Despite your lack of aerodynamics, seems decent duration. Is it a 4s pack and you're getting 30 minutes? what all up weight are you up to??
|Aug 17, 2011, 06:26 PM|
Yeah 4S 5000mAh.
Not sure of the weight, will have to measure but I'm sure it's on the heavy side as far as Skywalker builds go.
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