X-Cam Modifications for air use
10/5/01Wireless video projects
05/21/02 Things are working, but need a little tweaking. I've put a couple of images in here that you can check out. One is not mine, but an example of how high I would like to fly. At this point I need to:
Weigh the plane. It flys fine, but it will be interesting to know exactly how heavy it is.
Tweak the antennas. I am getting some dropouts. Could it be the aluminium gear?
Try other antennas. Stock dipole and the groundplane.
Eliminate vibration. I've added a isolating engine mount - it does not appear to make a difference.
Paint the wing orange! I'll have to look away from the plane during RPV flight. It needs to be more visible.
Then I can move on to more fun things, like writing my own code for the overlay, adding a volt and rpm meter.
This past month I have a new camcorder and a notebook computer for the project.
03/07/02 Very good news. The telemetry and high power (1W) setup works great! (in the house at least)
A few problems though along the way. First off, the PT-5041N DC-DC converter was being funny with the 1W transmitter.
The current draw was 3.5 amps (on a 4.8V R/C pack, 1100 mA). The wires were getting hot to the battery, and it would last only a few minutes. At least
I found a way to cycle my packs. I've made a 12V pack out of R/C car batteries, 10 of them. They are 2400 mA. I need to test the duration of
the freshly charged pack. The meter says 800 mA draw from all the stuff, as expected. The whole thing is very tiny, maybe 5X3X2 inches. Inside there is a
Oncore GPS (my second one - more on that in a minute)
Intuitive Overlay OSD-GPS
Byonics Tiny Trak II TNC
Plus a whole bunch of interfacing and power circuits. Here's why:
The Oncore GPS outputs 3v logic - supposed to be enough for the PIC (OSD) to read. But the GPS strings
go to the OSD board and the TinyTrak. So I've split them using a 7404 inverter/buffer. As well the TinyTrak is looking
for an inverted 5V logic input. I had a nice 3V LDO 8pin DIP regulator in there for the GPS. But I connected something
without thinking (DOH!) and it burst into flames with a loud hissing and smoke! PLUS the GPS was cooked! AGGH. So now there is a
LM317T (SMT) in there. Here's a great LM317 circuit that shows
resistor values for your desired output. I'm going to replace the LM317 reg with the LDO as soon as I get around to ordering more.
The output of the TinyTrak needs to be amplified as well to be used with the transmitter line input. I used this
LM358N Amplifier modified by removing "R1"
and attaching the output of the TinyTrak where the microphone is supposed to be. I used a 100K resistor for "R5".
The TinyTrak transmits the GPS data over the audio channel. The audio plugs right in to my computer - a notebook
will be used in the field - and the computer decodes it, displaying the position over a map, with the
APRS software. I have not decided which APRS software works the best yet though.
So...
Everything looks like it's ready for RPV flight! The only catch is...
the damn battery weighs a ton. I'm going to get a equal weight bag of bolts and fly it in the trainer
to test the flight characteristics before I put all that stuff in there! The whole setup weighs +- 4 pounds,
which I believe to be well within the trainer's carrying capacity. It's always best to test these things out first though.
I'll post pics of the setup soon, plus, if it all works a schematic and parts list so you don't have to go
to all the trouble of putting this stuff together by trial and error.
Val has moved ahead as well. Not only has he flown higher than 7500 feet, but much higher! Also, his plane flys itself to a GPS waypoint! So if he looses the video feed he can turn off his transmitter and the plane will fly back to the field by itself. He's going to try and break the AMA R/C altitude record, Something I would love to try as well, but I would hate to compete with someone who has been such an inspiration for my own project.
02/10/02 Ok, the trainer was repaired Friday night and taken for a test spin this evening. I've gotten pretty good at fixing damage :) so it did not take that long. Still waiting on the GPS interface chips. Digikey usually sends this stuff really fast UPS, but I chose USPS this time and it is taking a while.
02/08/02 Disaster. The new trainer went out for it's maiden flight and crashed. They were practicing "Quickie 500" racing out there and they had a flag pole at the end of the runway. The engine, a new Magnum .91, was not completely broken in, and would not yet idle. So the idle was a little high. The landing approaches were a little hot. After a couple or way to fast touch and goes it's decided I can either land the plane deadstick, or set it down, use the entire runway, and put it in the grass to slow down a bit. I opted for #2 and came in. Right into the pole! It clipped about 10 inches off the wing. The plane instantly went into a dive and hit the runway inverted, tearing the valve cover off the engine and spilling all kinds of valvetrain parts around. Someone yells "landing!" and I turn to tell them my plane is crashed in the middle of the runway, but they are now yelling "deadstick!" and they are going to try to avoid the crash. Sure. Smack! Right into the pile goes the plane. No real damage from that one. So, as of now I'm repairing the wing and the engine.
I got a 1 Watt tx for the video, and I'm waiting on a max 202 and serial buffer for the GPS interface. I'll have pics of all this stuff up soon. The transmitter looks to be a low-power tx, connected to a amplifier board inside the case. They have scratched the numbers off the amp chip, but at the RC-CAM forums we've discussed these amps and know what chip they are using anyway. I can't figure out why they would hide it.
Val has beaten his own record, and flown to 7500 feet. You can read the story on his site.
Here are the crash pics from last weekend: Pic #1 Pic #2.
I'd like to re-arrange the page here, but sofar I've been too lazy. The shorter days (even here in L.A.) are taking their toll on me and I can barely find the motivation to repair the damaged plane. I'd also love to get a faster connection here, so the videos will upload faster to you. The upgrade is $160 though, a little pricey for me to be dishing out files.
01/14/02 Currently I'm working on hacking the GPS overlay. I don't need the GPS co-ordinates on there, and I would like to add RPM. I'm going to attempt a homebrew telemetry setup. The systems available are great, but expensive.
I've ordered a .60 size trainer for the camera setup.
Also, Val Petrov has had great success with his 1W module, and has broken through the clouds, reaching 5000 feet! Click on his "flight log" to view the images and video. It is amazing.
10/27/01 I'm building all kinds of neat stuff. I came across this today. It's the really sad story concerning the removal of the MTV-7A transmitter, and more. I could always head to a hamfest with pop when I was a kid and end up coming home with one of their sub $10 kits. My sister and I would mess with these things for hours.
10/22/01 I got a new hi-res CCD camera today, plus a GPS overlay board, and a Hi8 video camera to record the videos. So in the future it shouldn't look washed out.
JPG image.The plane. This thing rocks! A Four-Star 40 w/ a .60 engine! Blistering speed.
JPG image.A little more camera detail.
If you are interested in this join us at the RC-CAM forum.
We are discussing the modifications and other transmitter devices there.
Send mail if you have any questions or comments!
Four-Star videos
Taking off!
Two loops, sun burning the CMOS camera up
Inverted, climb.
Loop.
Panning the camera in stall turns.
1/2 roll.
Cockpit view stall turn.
Bumpy but safe landing.
Neat stall turn leads to an inverted smack!!! You can see 2 planes zip by right before it hits.
Hog-Bipe videos
New CCD camera!
Looks like a Zagi to me!You'll need the DivX ;) codec for these.
These videos are larger than the RealPlayer clips, but the image is sharper.
I messed with the antenna, and it has less range than before. The new CMOS camera
looks great though. Cloudy day.Takeoff! 5.2M
Another takeoff. 6.5M
Loop. 1.1M
Another loop. 2.3M
Low pass. 1.9M You can see the bad range here.
Another plane passing in front. 700k
Basic roll. 7.5M Other plane visible!
Oops. Taking the wave-off. 1.7M
Landing the bipe. 1.7M
01/12/02 New videos. The camera was moved to one of the outboard struts in an attempt
to keep the oil off of it. This worked, but the wind resistance would always yaw the plane to the
left (visible in the videos, look for it) Tested both the Linx and
MMIC upgrades. The quality from the MMIC
was poor. I'll try tomorrow with a different antenna. The video from the Linx amp mod was great, I went as high
as I ever have with it. I'm only getting static when the plane is banking and the antenna is pointing away.
The landing vid is entertaining to say the least. First of all the yaw from the camera and panning servo
put me over the grass, which as you can see, Hog-Bipes hate. Adding insult to injury a warbird
passes over right after the tumble. No damage, flew again after inspection.DIVX ;) videos.
Interesting take-off view, low quality avi. 1.7Mb
Interesting take-off view, high quality avi. 6Mb
Flying around, low quality avi. 3Mb
Flying around, high quality avi. 8.6Mb
Landing accident, low quality avi. 1.7Mb
Landing accident, high quality avi. 6Mb
JPG image. After the crash. Total loss.
JPG image. Barbie survies again. I am beginning to think she has something to do with these four-star crashes. Oh well.
Ok, things learned. The transmitter works great. The camera sucks. I'm going to buy a CCD button camera, and another plane :). If I make a mount for the antenna I may get less dropouts. It was pretty much blowin in the wind back there. The panning servo is nice. I did not pan too much in the videos. Here's the servo mod for 180 degree servo movement.
Great project, thank you Dave!
