steve_molmer

Dave,
I am using two different auto pilots rite now.
A BTA – 07A with the gps return home setup. I have modified the gps so that it will fallow up to about 20 wave points. It works very well. The other unit is a do it your self Auto pilot using the r.cap board that is mentioned on many of the forums. It is riddled with issues at this point but it is a work in progress.
If you are just trying to stabilize the plane for video or to get snap shots the BTA –6 or the 7 do the trick quite well. With ether unit on all you need to do is use the rudder to turn the plane over the target so to speak to get your shot.

For a good onboard recorder you can use an SD base recorder. They are very small and work just like a VCR. You will need to invest in a good CCD video camera that has at least 520 lines of resolution for good quality video. Note. Try to stay away from a Cmos based unit as they take a grate deal of light to work properly and they do not work well at all when you add vibration in to it. Also look for one with an adjustable shutter speed. I am using one made by WYTEC. I will post the part number later for it.

For the money Bill’s setup works fairly well and he has it on a big gasser, and it seams to handle the vibration. I am not sure of the resolution on it. I think that he mentioned it in one of the previous post.

When I fly I use an OSD board that is attached to the transmitter. It allows me to add text by a key board or by microphone. The telemetry is taken from the GPS 18 I have on the plane. The setup is about $350.00 Dollars to build and is worth every single one of them.
With this setup I can fly the plane out of site and still be able to find my way back.
On my ground station the live display shows my longitude and latitude. When I am heading away from my takeoff point the text is yellow when I am running low on fuel or if I am starting to get out beyond a preset distance I will hear an alarm and the text will turn red. As I am returning, home first the longitude will turn white when I am lined up with the original heading point, when the latitude is getting close to lining up it will first blink then turn white as I get over the starting wave point. (working in conjunction with the auto pilot and a few bits of my own) If I loose control or if I have rc transmitter issues the auto pilot will fly the plane back over the field. (If the BTA-07A is turned on)

One thing to remember here is to do things in small steps. The easiest way to end up with an empty wallet and a large area of wreckage all over the field, is to try to add all the bits to your plane at one time. Trust me I have gone down that path. Not fun.

Best regards

Steve

wjglynn

Steve-Dave,

Since you two are antenna guys I have a new question. I am all geared up to build a ground plane with Steve's coaching for my commercial 8db patch antenna. Recently I ran across plans for a homemade patch antenna on www.rc-cams.com. It piqued my interest as the antenna screws directly on the reciever averting lead-in cable loss. Steve, your ground plane tuning has been done with commercial antenna's. Do you think that your ground plane spefications would be valid for any 2.4gig patch including this homemade one? The dimensions look the same as the white commercial ones. I have the parts to build this homemade antenna and am curious whether your gorund plane would be another improvement to it.

Dave, I have posted videos shot with an Aiptek DV and more recently via a BWAV KX-131. My next flights will be with a Nikon 5400. It is a 5 megapixel still camera with capability of 640x480 video. I think that it shoots at 30fps but do not remember for sure. I will shoot some video with it but will be concentrating on air-to-air still photography. My new heavier landing gear is installed and the counterweight bracket is almost finished. I chose to attach the needed 7oz. of counterweights to the engine casing bolts right behind the flywheel. I will be trying to hide the weights behind the flywheel as much as possible to minimize drag. I have enough of that already. I redesigned the engine mount to better distribute the stress on the firewall and have made some improvements to the camera mount. I will post some pictures when I am finished. Hope to fly it on Sunday, weather permitting.

Steve is way ahead of me in this game. He has done great work and has really good advice. I agree with his systematic stepwise approach methodology. There are just too many variables to manage any other way.



Bill

wjglynn

Well guys, here are some pics of some of my most recent mods. With the Nikon 5400 on the back and 7oz. of weights on the engine just behind the flywheel the Rapala digital fish scales says that it all weighs just over 19 pounds. I have added new 3/16" landing gear to better handle this load. (The original ones were collapsing when the plane was at 18 pounds.) The picture also shows the new steel square tubing used as motor stand-offs and an aluminum plate to further spread the weight loading across the firewall. While the plane was apart I also tightened up the camera mount linkages by replacing clevises with ball joints on both the tilt and pan. I also added springs to the both sides of the tilt platform to help dampen travel. My tilt linkage had previously had a tendency to over center due to the short length of the lever. I added an arm to lengthen its throw and increase the servo's mechanical advantage. If I have time before Sunday I will assemble the "Goof Proof" patch antenna to test it also.

Shoot and Share!

Bill

wjglynn

Well, here are my less than impressive first attempt at air to air stills. Unfortunately the stock Nikon video feed cable did not like the environment it was in. I hardly ever was able to see what the camera was seeing in flight. More shielding work to do with this camera to suppress interference. The captured ground video was too poor to even render. Here is a self protrait of me with the video goggles, mount controller, and ground station along with the few shots I was able to make with a plane in the picture.

Bill

steve_molmer

Bill,
The shots are not that bad.
They look pretty good when take in to account you took them from a moving plane of a seen of a moving plane, and to top it all off you were on the ground controlling the plane at the time. Last time I looked it’s not that easy to do.

Sorry to hear about the problem with the video feed. I can not tell how your transmitter is mounted inside the plane but if it is being vibrated by the engine it could be the source of the problem. I have always used 2” thick foam to rap the transmitter to get rid of the nose or distortion that can be seen on the video that this vibration can cause. (residence or harmonics generated by the engine at certain rpm’s.) One more thing to look at that is also not an RF issue; I see that your antenna is directly mounted to the transmitter as it is coming directly thru the fuse. I would use a piece of ½” pipe insulation to go around the part of the antenna that goes thru the fuse of the plane. This would prevent the vibration from traveling into the transmitter from the antenna.
Hope this helps.
Best regards

Steve

wjglynn

Steve,

Thank you very much for the feedback. You are giving me some good pointers. The transmitter's antenna base is inserted through the plywood plate with a rubber grommet. What changed from last week is the camera itself with a different cable to the transmitter, the Nikon has two additional servos mounted on it in close proximity to the transmitter, and I may have a damaged antenna. The factory A/V cable does have a ferrite core filter a couple inches from the camera but I did coil all the excess in a loose loop around the transmitter. I moved it for the second flight stuffing it in the fuse ahead of the mount with only slightly better results. Operation of the mount seemed to greatly affect the video quality. The transmitter is now in close proximity to three servos whereas last week only one. Since the video picture came and went with camera mount operation I guessing that the cracked antenna knuckle is not a contributor. (I repaired it with glue.)

I think what I will try next is to move the transmitter from the bottom of the plane to the top of the wing in the middle of the fuse. I will build a pod from a Rascal wheel pant mounted on a bracket and secured with the wing bolts at the trailing edge of the wing. Then I will make a shielded A/V cable and tape it to the top of the fuse with that clear aileron tape then run it back to the mount. In this manner the video signal will come off the camera outside the fuse and run away from the mount up the fuse about a foot to the transmitter now mounted externally. Inside the wheel pant I can suspend the transmitter as you suggest with foam for vibration suppression. Have you had any experience with the antenna on the top of the fuse?

The camera has a tendency to want to autofocus on any part of the plane extending into the edge of view slightly blurring my target. That can be addressed inside the camera settings. Due to video quality I was only able to zoom once. If I can get my video consistency back to what I had with the BWAV KX-131 I am very optimistic about potential results. I am still trying to find time to build the ground plane for the receiver unit. Perhaps this week?

Thanks again,

Bill

steve_molmer

Dzbum’
This is more than a legit question for this post.
People make this type of small issue into a big problem.

On all the Lift Master’s that I have setup as platforms for UAV and video I always tried to fallow 3 main rules when I build a setup like this.
1. As always use the principle of “KISS” (Keep It Simple Stupid)
2. Do it rite do it once, Do it cheap do it over.
3. Try not to let rule two override rule one.

Looking at what you are trying wire up, I do not see the need to add all the additional problems with a dc to dc setup as the 1W video transmitter will take more current than it can produce to function without burning up from the load.
For the equipment you have listed, you will need a 11.1 LiPo battery rated at 2 Amps and 10c. (this should give you about 2.5 hours of power.)
1. This battery will directly run your 1W transmitter and camera.
2. The RCAP2 can also run off the same battery if you use a diode in series with the connection from the battery to it. ( keep the unit as far away from you video transmitter as possible)
3. Now, Using a switching regulator like the DE-SW050 by Dimansion engineering to run the Geko. From the output lead of the reg add a diode (IN4001) in series with a resister (determined by the 2 volt drop and the current that the Geko pulls) this will connect directly to the power input of the Geko.
4. tie all the power grounds back to a single point and connect up to the battery.
5. do not try to pigg-back-power connection off of the RCAP2 or you can stand on the ground and wave goodbye to the plane when it locks you out of your RC controls. (I have seen the problem many times, it’s an issues with cross talk or data running back into the EPROM power pin generated by from the jumped power connection.)
6. The FMA Copilot FS8 should be run from the RC battery and not the same battery as the other equipment.

I hope this clears things up.

Steve

S_Dave

Steve,

Thanks for the reply and the very helpful information on your autopilot setup. Your comments about taking small steps--those points are well taken. My current plan for my own AP efforts involve applying that suggestion: 1. get the plane up and become comfortable with it (in my case, a Goldberg Piper Cub with roomy fuse interior). 2. Add a small video camera (I have a 480 line CCD color video camera) and 2.4 GHz transmitter (got one from SpyTown). Get this working okay. Next, 3. install a small GPS to ride along. Nothing fancy, just download its track log on landing to overlay on a Google map or something. ...then, 4. install a 900 MHz RF modem to downlink the GPS pos'n into a mapping program, like DeLorme streets & trips, etc. Then, read more posts from you and Bill and see what you guys are doing.

You guys are both flying some impressive systems in your planes. There's just something really great about getting video and pictures from your R/C planes.
Cheers,

Dave

S_Dave

Hey, Bill,

Those are fantastic pictures! That took some doing to snap the yellow plane while in flight. Don't believe I've seen that before on the web.

Your flying spot at the field is pretty impressive with the good-looking instrumentation on the tripod, and what looks like a weather vane, too. You guys have a very nice grassy field to fly on. Our site is on top of an old landfill, and the grass is just here and there. We're not sure if the occasional trickle of methane keeps the grass from doing well, or just ignoring and not watering it is the reason.

From the short sleeves (in your first, self-portrait shot), it looks like warmer weather has arrived in KS, too.

I've been out of town for several days, and was glad to read some of the recent posts from you and Steve. You are both doing a great job documenting your projects, and I'm sure many people are benefiting from your field research (not meant to be a flying site pun).

Cheers,

Dave

S_Dave

Bill,

Just read again your earlier post about the autofocus issue. I'm doing a project for work where we carried a 10 MP Canon DSLR aboard a helicopter. To get the biggest field of view, we carried the camera payload as far aft as possible, but the helicopter skid is just in the image. Our Canon was trying to average the scene, skid vs. ground 600 ft below, and did a pretty good job. However, the focus is a tiny bit fuzzy due to the skid being in the foreground. My digital camera friend gave me a new setting to use that forces the camera to infinity focus. Sounds like you already are planning this option, but I wanted to mention it. Here's a sample picture over Clarkston, Georgia. The second is a mosaic of eleven images in a sequence. The skid(s) in the RH side are illuminated by the afternoon sun--these are going West-to-East. In the LH side, the flight is East-to-West. A little distortion using the mosaic program (www.autostitch.com) but interesting.

Cheers,

Dave

wjglynn

Dave,

Thanks for the kind words. Our great flying site is due to the efforts of Bob Longyear, our local hobby shop owner (Dee and Mee Hobbies) who owns/maintains the field and invites the public to his field to fly and recieve free lessons on Sundays. He has a great facility and we are fortunate be the benefactors of his philanthropy. For a few weeks we will be camping at the south end of the regular pits while Bob's huge investment in new grass takes root. The greatest thing about this hobby to me is that the people in it readily share what they know and give to each other. Bob (He is my photo GBS pilot too.) seflessly shares with the public and Steve here is doing the same thing on this forum as is many others. It is a great hobby!

What you are seeing in the picture is my last year's father's day present from my wife. It is a Kestral 3500 weather meter. I built the "Wind Stik" to keep it pointed into the wind. It tells us wind speed (avg/current/peak), temperatures, pressures, humidity, heat indexes, and other useless facts. All of which are great conversation fodder for the pits. Why, with a tiny servo attached, we could mount it on the plane, point the camera at it and do our own airborne weather report. (That might be just a little over the top, even for us.)

Bill

wjglynn

Dave,

That serve was long I'm telling you! I saw it perfect from here! No way was it in-bounds! That was matchpoint! I win!


Yes, those darn cameras have gotten too darn smart for their own good. I expect I can set the focus area to just the center of field so it ignores the edges. Thanks for the input. For now I plan to stay away from infinity. There is a possibility my target might be closer than that. Next time I will be shooting at hi-rez and burst mode.

[8D]

Bill

dzbum

My Feedback: (5)

Steve,
Thanks for the info. I agree about the KISS part. I am a network engineer and the most common form of network outage is caused by being overly redundant.
I had come to much the same conclusion as you are suggesting use a 11.1v LiPo to power the Camera + TX straight from the battery. The RCAP will also run from the battery and should be fine down to 6v or so ( a little redundancy there ) I’ll build a 3v regulator as you suggest for the Geko as I have heard bad things about using the internal power in a high vibration environment. I will take your advise about using a common ground for all devices. I am planning on putting the TX and camera in a pod out on the wing and the Geko and RCAP out on the other wing to balance it out. This will give me the separation. I will put the Battery in the fuselage.
Thanks for your help advise.

Brett Horton

My Feedback: (17)

Hey Guys,
Where can you get the BTA 07 auto Pilot? Is this the route to go for way-point flying ? I have tried to contact the manufacturer with no luck, any ideas?
This unit is going in a Lift Meister.

Brett Horton

My Feedback: (17)

No replies? Steve?

wjglynn

Brett - Steve is on the road a lot so he is not able to reply as fast sometimes as those of us flying a desk for a living. Give him some time.

[8D]

Bill

dzbum

My Feedback: (5)

Brett,
I cannot help you with the BTA 07, but if you are looking specifically for something to do way-point flying you should check out this thread. [link=http://www.rcgroups.com/forums/showthread.php?t=515929]Making a WPS[/link] There is also talk of adding 3D WPS to this already done Altitude hold project so that you can adjust height along the route. [link=http://www.rcgroups.com/forums/showthread.php?t=633795]Altitude hold project[/link]
Hope this helps.

Simon

steve_molmer

Dave,
Let me know if I can be of any more help, sounds like you are just about to get this ready and start the ball rolling.

Brett,
As Bill said I look at the post every time I get a chance but I am away from the web quite a bit as my job sends me out on site every so often.

The BTA auto pilot comes out Israel. Now the full version is not sold to the general public. You can get a hobby version that has the GPS home function at the MPI site I think its part number is BTA AS-07G. The link to the web site is http://www.maxxprod.com/ Now it is not cheap by any means but when set up it is as stable as a rock in the air. I have flown it in every non military platform that I have built for over 5 year now since the BTA-6 unit was discontinued and it has been a real dream to deal with.

I Have been building a lift master for a friend of mine that is handy-cap and flies rc from a wheel chair. I have the plain BTA AS-07 in it and so-far it seems to be pretty good for stabilizing the plane. As soon as I get the ground station set up for him I will post picts and video.

Simon,
Those are very good projects that you are referring to. Just remember that with any of the information that you find out there like this is extremely experimental. If anyone is going that way make sure you do your test on a cheap plane and out of the way of population.

My first real UAV cost me a large sum of money when it went into a yard and took out most of a flower bed and the top of a gazebo when my original auto pilot lost its mind and went 2 miles off course. That was over 18 years ago, that is why I adopted the above entry mentioned rules.
They have yet to fail me.

All,
Best regards and have a good week.

Steve

dzbum

My Feedback: (5)

Steve,
thanks for your help. I ordered a 11.1v 2000mah LiPo. Given the Geko will also run on 2.4v (2 x Nimh's) can I get away with a DE-SW033. This would give me 3.3v - 0.69v (diode drop) for a total of 2.61v, or should I go with the 5v reg with a resistor?

Thanks
Simon

Brett Horton

My Feedback: (17)

Not being pushy...
Thanks for the info.

S_Dave

Steve,

It was great getting to meet you at the CCRC field on Friday. You certainly have a lot of hard-earned knowledge and experience as evidenced in the well-built and equipped Liftmaster plane you displayed there. Thanks for taking time to chat and for sharing all the good tips on this site over the past weeks. I look forward to seeing you again at the field, and trying out some of your tips on my own airplanes.


Bill,

The TV is showing footage of bad tornadoes (is there another kind?) in Kansas. We hope those are far away from you and yours.
I'll be looking for your next post to verify that you're okay and still flying.

Good flying weather here in Georgia, cool and mostly sunny with a nice breeze. I'm working on several planes at once, trying to get some ready to take up and begin getting back the "touch." They say that good R/C flying is all luck; the more often you practice, the luckier you get. Hmmm......

Cheers,

Dave

wjglynn

Thanks for the concern Dave! The Greensburg tornado was about 200 miles southwest of Topeka. Topeka was hit by a similar mile wide tornado in 1966. There was lots of tornadic weather here last week. Many funnels sighted across the state and a few touchdowns. We got about 6 inches of rain last evening on top of the already saturated soil and swollen rivers. This morning they are evacuating people from the middle of town which I have never seen before. Flooding a big concern here presently but the weather pattern is clearing. Our biggest concern is the new grass being washed from Bob's rc airfield.

Two new antennas have arrived and I have begun modifications to the transmitter installation. I am moving the transmitter to be mounted outside the fuselage and in very close proximity to the A/V port on the camera and padded/supsended in a manner Steve has suggested. I am trying to minimize the length of the A/V cable and try to run it away from the servos. Since I have flat real estate on the bottom of the fuselage I am going out on a limb and mount a standard patch antenna there to see how it performs. I will be asking two left handed circularly polarized antennas to talk to each other. I will leave it to you antenna gurus to speculate as to how bad of an idea it is? I also have a new Astron vertically polarized 3db round disk antenna to try. Installing it will require a refab of the wooden plates on the fuse so drilling holes on the present ones for the patch test is no big deal if the patch on the transmitter fails to perform. If I don't get it mounted this week and fly on Sunday it will have to wait. We are leaving for Joe Nall a week from today.

Cheers!

Bill

steve_molmer

Simon,
As per,
The diode was for electrical isolation. Connecting the unit up to its own power source makes this a mucked point. Now if I understand what you are saying at this point that the unit can run off of a battery down to 2.4 volts and up to 5 volts then the 3.3 volt cell should be fine. I would take a look at what the current draw is at the 3.3 volt range. As a general rule when you lower the input voltage to a device the current load will increase directly. This will affect how long the Geko will work off of the 3.3 volt power source.
Just a thought…

Steve

S_Dave

Bill,

Glad to read that you're not in the Land of Oz after all those tornados!

From your quote above, are you saying you have a LHCP antenna on your plane and a LHCP antenna on your ground station? That should work fine--although it being Monday, I had to have a "reality check" from two other antenna engineers to convince myself that it would. There was a lot of finger rotating going on here for a while, I'll tell you, as people described E-field vectors spinning through space, etc. In some communications systems, like radar, a radio signal changes polarization when it reflects off an object, so as you supposed, the sense has to be considered.

Are you bringing any planes to fly at Joe Nall? Lots of guys from our club are planning to attend and they make it an annual pilgrimage.
Best regards and keep dry out there,

Dave

steve_molmer

Dave,
the feeling is mutual.
Look forwarded to seeing back out at the field.
I am planning on postings a how to setup a video transmitter walk throw so to speak shortly.

Bill,
Glad to hear you avoided the big twisters out over your way.
Mother Nature can truly get medieval when she wants to.
The experiment with the two patch antennas is a good demonstration that will show you just how good your transmitter and receiver are matched. I do not want to put a damper on this or keep you from doing it, but when you mount a patch on a moving object and you have a stationary object on the ground that your other patch antenna is mounted to, you will only have a good signal when your plane passes over the other patch. When it passes beyond the phase angel of the patch the signal level will fall off dramatically and then be lost.

I know this will sound a bit nuts but a cheep way to make this work is to attach the receiver patch to the front of a helmet that you as the pilot will have on so that the two antennas will always be pointed at each other when you are flying. Now at low altitude you will get a good bit of breakups when the plane gets away from you or in a turn but it should work. I have seen quite a few helicopter uav’s use this in the past.
Regards

Steve