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kd7ost

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About kd7ost

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    RC-Cam'er

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    Southern Idaho
  1. For what it's worth, Lipo batteries perform pretty well in the cold. So do Nimh. Not Nicds though. As they get colder they can't spply the higher levels of current needed for max on your motor. I wouldn't think there should be a problem with the lower current draw of the AV system. Dan
  2. You might concider one axis on the camera, and one axis on the craft? It will be easier and the craft will already have yaw capabilities I presume. (Pan) Dan
  3. I like that idea. We've also been talking about the "Way Point Sequencer" on the other site. What I would like to see is the ability to have an altitude lock as you describe. Couple that with a GPS enable type device. In this case you aren't loading in waypoints, but the electronics is looking at Lat and Lon from a GPS. You can fly via RC and Video link to a specific location to photograph or observe. Once you manually fly to a location where you want to loiter, enabling the device will lock in the altitude as well as cause the plane to start to loiter around that location. It would stay that way till you take it back by disabling the unit. The pilot at that point can focus on filming or shooting pictures. It would be a workable solution for first responder type folks at accident scenes with chemical spill's, etc. We aren't talking to far away in this case. Not outside the range of the stock RC system. I should bring it up to MX over there. Dan
  4. A full scale pilot also has and uses trim tabs to help in flight to balance keeping altitude, speed and pitch setting where they want. I find in my UAV style plane, with a fair amount of adjustment and tweaking the setup, that full throttle causes my plane to climb. I don't have to touch the elevator once I have rotated. It will continue to climb but no tendency to stall until it were to run out of fuel or lift. Then watching the video Link and GPS overlay altitude information I know that by adjusting my throttle I can get the altitude to stay reasonable steady where I want. At this setting, I can employ my UNAV Pico Alt E and it will keep it in place right there by adjusting elevator. The gain is set pretty low though. If I advance the throttle at this point, it will porpoise slightly if there is enough gain to keep it at altitude. If I let off a little gain in the Pico Alt, it won't hold it in place while powered on. Thrust at just a few degrees positive will overcome the light setting in the altitude hold. I can smooth out the porpoising by reducing the engine thrust. But then I'm back to using elevator to get altitude. That’s OK at low altitudes but when you get high enough that you can't tell how much pitch you're using to keep your climb rate, it's pretty easy to over do it and stall. Low altitudes give the pilot the ability to manage it all. But it's very nice to have the plane set up so that it takes care of itself with just throttle once the pilot is more distant. I also have the balance set up so that from a spec in the sky, I can simply reduce throttle to an idle and the plane will loiter its way down. No elevator needed. Again, it simplifies the pilot’s job. Sorry if this seems a little off track. I have gradually turned from using a well set up RC plane to finding it's better for me to have a hint of full scale operation. Leaving the elevator alone is a big help. (I do use it of course for take off and landing) I would also state that this is going to vary in ability to dial in when you consider Power to weight/ lift etc ratios as well as how much wind there is. I feel the smaller and lighter the plane is, the smaller of an operational envelope you can safely operate in when flying autonomously. My plane is a big gas powered plane at 22 pounds and 50 mph flight speeds. The Pico Alt comes in a T and E version. The T stands for throttle and the code is optimized for using a throttle for altitude hold. The E version is for elevator and the same applies. In the end, I think they are both workable solutions. If you set your plane up so the power changes do not cause pitch changes, you can easily use elevator to do the job if you have enough motor/engine power, and minimize the elevator deflection. Don't let the altitude hold give your specific plane full elevator deflection. If however you set the plane up to climb with full power, the throttle would be a better control to keep altitude IMO. I would also like to state that even though I have experience with these systems over the past few years, I'm not an expert. Dan
  5. kd7ost

    Mid Life Crisis

    I'm embarrassed to say I have a few of those chips programmed up but never used. One of each two flavors in fact. It seems like the Helicopter guys would use them the most. Where there are two operators. One for flying the machine and one for flying the camera. At the time I was designing my early UAV and thought I needed pan and tilt in a camera pod. I had a buddy of mine at HP download the files and program them for me. In the end I use a standard Futaba 9001 servo for tilt, and my rudders for panning. It’s a lot less complicated and allows me to be the camera and aircraft operator both. I also recently discovered, thanks to my buddy Mike Robinett, these servos by Jim Frye at Lynxmotion. http://www.lynxmotion.com/Product.aspx?pro...9&CategoryID=38 They are cheap and come modified for continuous rotation. The cool thing about them is they come with a pretty large dead band built into them. Once you center the trim tab properly, they don’t hunt or move. There’s a small amount of stick motion required before they get under way. They do suffer from not getting held in place though due to the removal of the feedback circuitry so are only good in low force application. They will move if you put a little pressure on them. That is certainly what sets your project apart though. With the pulses holding it in last position it’s a more professional approach I think. Someone can fly the helicopter with some serious G’s and the camera won’t get spun around. (Now that I’m caught back up on how it works) I would venture that the reason it’s not as popular is because AP helicopter guys are more interested in ready to use off the shelf applications. The DITY projects are for the few hardcore builders. Anyway, sorry I’m getting off thread topic here. Dan
  6. kd7ost

    Mid Life Crisis

    OK, then it's like you said, it just hasn't made it that far yet. It seems as if inertia was making it overshoot, then it would stop and then move the oposite direction to come back to where the pulses are telling it to be. It might simply be that with a well balanced unit you could get away with using a servo like one of these 1/4 scale versions. http://www2.towerhobbies.com/cgi-bin/WTI00...L=++&search3=Go Best of luck. Dan
  7. kd7ost

    Mid Life Crisis

    Does the pencam chip continue to put out pulses based on last position information though? Or does it stop putting out pulses when you aren't moving the stick? Dan
  8. kd7ost

    Mid Life Crisis

    Bummer. Drats is right. Sounds like you pegged it though. So in this case, it sounds like the transit time for the servo is too slow. Having pulses stay there will certainly prevent overshoot from coasting the gear train. Can you increase the gearing any in the Robotzone device? Maybe you can try a high speed servo to raise the transit time. Do you need the full 90 degrees of motion in the servo unit? Maybe changing out the potentiometer to a different value, or simply adding some fixed resistors on the ends of the pot will provide less motion but increase the response time within that range? Maybe you can move to a large 1/4 scale servo and go direct drive off that. You might have to make your own servo/gearbox combination. There are a handful of good proportional H bridge speed controllers off the shelf. http://www.dimensionengineering.com/ http://www.lynxmotion.com/ Just thinking out loud here. It sounds like you could use a servo made from a skill twist style cordless screwdriver with built in dual planetary gear boxes. Dan
  9. kd7ost

    Mid Life Crisis

    Oops, So much for my idea then. It sounds as though you already have a handle on the HD parts. It sounds like the 5 pounds mass of the camera, is keeping the servo in motion through inertia. The increased gearing is giving the mass an effective longer lever arm. I don't know the panncam device, but it sounds like when it's time to stop motion, center stick, that no pulses are being sent. What if you try to operate the camera/servo device right off the receiver? Put in on a channel with a stick that spring centers and see if it stops it when the stick is centered or if it overshoots. Dan
  10. kd7ost

    Mid Life Crisis

    You might consider changing servo's too. You may already have it nailed down but servos like the Airtronics 94738, Futaba S9405 et al are high resolution, lower speed and higher torque mechanical devices. They use coreless motors and metal gear trains. You might also look at the products from some of the robotics mechanical companies. Take a look at servo modification projects from http://www.servocity.com/ These slow down the mechanical action, and increase the torque. The servo city parts would allow you to use a servo like the Futaba S9001. There are other servos that will work too. I just know those ones off the top of my head. I would recommend servo’s with coreless motors. You can get three pole, 5 pole or coreless motor servos. The three pole motor servos have the most obvious “stepping” action in a video system. This prevents fluid motion in panning when moving very slowly. 5 pole motors increase the resolution but it still “steps” from one position to the next. It’s not very obvious when you’re watching a control surface move. But it’s evident when you’re using the servo to pan a camera over a distant scene. The coreless motors lack the pole steps. They do cost more but are higher quality as well. They have the finest motion resolution or fluid action. I admit to being programming deficient. I look at mechanical means. The software tweaking will work much better if your mechanics are matched to the work load. You came to the right place though in talking to Mr. RC-Cam. Dan
  11. kd7ost

    180 Degree servo mod

    Here's a hardware mod if anyone is interested. Dan http://mypage.yhti.net/~dmcdnld/s148retract.htm
  12. kd7ost

    FMA FS8 copilot hardware

    So the 4015 can be used as a level shifter? You just gave me an idea. Would the 4050, noninverting Hex buffer, do the same thing for up to 6 channels? Any idea if there is a single chip that would do up to 8? Dan
  13. kd7ost

    Saturn V Launch Umbilical Tower

    Mmmmmmm, food grade servos. There are a lot of options. There are some that are pretty well sealed. How much torque does the servo need to have? I'm sure the arms will be supported on there own with the servo just doing the motion part. Servos come in many price variations too. Do you have a spending limit on such an ambitious project? Dan
  14. kd7ost

    Radiohound

    Maybe the contact information you're using is outdated. Try this one. http://scalerobotics.com/store/catalog/ Radiohound is part of an active group holding pretty much daily discussions about the RCAP development. He has been very available to us. Check this thread for the latest. http://www.rcgroups.com/forums/showthread.php?t=484568 Join in over there. We'll look for you. : Dan
  15. We have to stop looking to the PDC-10 guys. I tried my best please, please, please, to UNAV but the deal isn't on the table. It's a pragmatic business decision and I respect them for it. The code represents a great deal of intellectual property and much of it resides in their new Pico pilot. The owner told me the PDC-10 represents a lot of work and effort for just too little in return from a business standpoint. As I said, I do respect the decision. It's not a hobby for them but a way of life. I suggest we continue to support Walter with the RCAP unit and its development. That is what I intend to do unless someone else can come up with other viable options. Dan
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