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Assigning parameters to a poti

Discussion in 'Cinestar Misc' started by Dave King, May 9, 2013.

  1. Dave King

    Dave King Well-Known Member

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    If I wanted to assign a parameter such as Gyro P to a Poti how would I do it? I know that I will use a Poti that's not being used, would I just type in the poti next to the Gyro P where there would be normally a number? For example if I have Poti 7 unused and I wanted to assign Poti 7 to it would Gyro P say Poti 7 on the Gyro page? I wanted to make sure before I tried it this weekend.
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Yes. Any value in MK Tool that has a single down arrow to the right of it can be assigned to a POTI -- just click on the arrow and you'll see a drop down list. Then you assign the POTI you've chosen to an RC channel in the Channels window, and finally assign a control on your transmitter to that channel.

    Be advised that, because you're using a control on the transmitter, you can assign a "crazy" value to, say, Gyro P, and that may cause you some "interesting" flight characteristic problems. So proceed with caution as you may end up biscuit-tinning** your Cinestar.

    Andy.

    **A technical term for a ground impact where all of the remaining aircraft bits will fit into a biscuit tin. Not considered a Good Thing by most pilots. ;)
     
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  3. Dave King

    Dave King Well-Known Member

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    Thanks Adny

    If I assign a rotary dial on the MX20 to say GYRO P, how do I know which value is at which position? This way I know that I don't want to go past a certain position on the switch if I know the value is completely wrong.
     
  4. Gary Haynes

    Gary Haynes Administrator
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    Only safe way that I know of is to do it on the ground with MKTools running over wireless so you can see the results.
     
  5. Dave King

    Dave King Well-Known Member

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    Thanks for the reply. Sorry all the questions but I want to make sure I understand this completely before trying. How do you know what the value of a gyro D (live actual number) would be for example in MKtools if its assigned a POTI in the function? Where would you actually see a number like 10 or 8. I would at least like to see what the actual number is as I adjust the knob.
     
  6. Gary Haynes

    Gary Haynes Administrator
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    I would think you would see it in the appropriate MK settings screen. But not having ever tried to this live I would test it on the bench.

    I seem to remember that Thiago has a video where he did this. Check YouTube and Vimeo for Drones4You and look for one of his videos from last year.
     
  7. Dave King

    Dave King Well-Known Member

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    I said screw assigning it to a pot and played with it in small 2-3 increments. I found my GPS D to be best at 14. It was just a little too slow to get back to neutral at 10.
     
  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    That was probably the safest way to do it -- the problem with a POTI is that you can really get crazy high or low settings if you're not careful.

    Andy.
     
  9. Steve Maller

    Steve Maller UAV Grief Counselor

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    I just tried this myself, and like Dave, I don't see a way of confirming what the actual value I'm setting is. Do I look at the value for that Channel (0-255 or so) in the Settings tab in MK Tool?? I also see an issue where the granularity of the dials on the mx20 is >1 per click of the dial, so if I wanted to experiment with Gyro D (which seems to be a Very Interesting Parameter), I can't reliably inch it up by just one (say from 17 to 18) reliably.

    Thoughts?
     
  10. Dave King

    Dave King Well-Known Member

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    Steve are you still experiencing vibration? I never figured out how to do that and I didn't want to experiment as its too risky for me. I'm using a Gyro D of 14.
     
  11. Gary Haynes

    Gary Haynes Administrator
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    Steve from memory if you go to the relevant item in MKTools and look at the drop down for values it should have the Poti "X" on the list. Determine what channel you want to run it on, look at the channels tab to see which Poti is assigned to that channel and then change the value for Gyro D. Suggestion from watching Thiago's videos, it is a bit imprecise, change it on the ground not in flight :eek:. If you have the wireless Xbee setup you could watch the changes while it is on the ground. Of course if you have wireless you don't really need the Poti.
     
  12. Steve Maller

    Steve Maller UAV Grief Counselor

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    I am not sure where to see what the value is after I've changed it. Is that in the Channels tab?
     
  13. Steve Maller

    Steve Maller UAV Grief Counselor

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    Is there a straightforward way to change the resolution or granularity of the POTI so it increments in exactly 1 tick for every movement? And again, I'm not sure where to see the actual value I've assigned with the POTI (in MK Tools). Can somebody answer that?
     
  14. Dave King

    Dave King Well-Known Member

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    Steve I don't think you can do what you are trying to do with the MX20. If you are trying to get vibraton out of the copter go with the lowest Gyro D that you can without it wobbling. I've heard of guys running a gyro D of 7. You might also want to try all blue orings since you have a mix of red and blue.
     
  15. Steve Maller

    Steve Maller UAV Grief Counselor

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    What about the mx20 would preclude this?
    That's the TX that Thiago's uses in his videos.
    BTW, I'm running Gyro D of 18 after trying everything from 10-30.
     
  16. Dave King

    Dave King Well-Known Member

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    Steve I can't see anything in the maual that would allow you to change the resolution or granularity of the POTI so it increments in exactly 1 tick for every movement. I think the best you can do is to set the knob all the way counter clockwise on the ground and then see what that gives you for Gyro D. Move the knob one click at a time and map out what each click gives you. IF you know you are in the safe range, you can experiment in flight based on the knowledge of what each click will give you.

    I know you were running the APC props which are better for vibration than the XOAR props but have you checked the balance on them? If you take the props off and on a lot you might need to check the hub balance as I have seen them off.

    I also seen the following info below posted by Gary
    There is an iPhone app called Vibration that several people use. Basically you strap the iphone to the boom and run the motor up without the props on. Then through trial and error you put on a piece of electrical tape maybe 3.8 inch wide, run the motor again, check the indication and then move the tape to a new position. Keep repeating until you find the sweet spot.​


    Not sure what you are using for a prop balancer or types of props. I tried both the magnetic kind as well as the DuBro Tru-Spin. The DuBro does a much better job, at least for me. Props are probably the most critical followed by the motors. Yet I know of some members that do nothing. They get it as close to smooth as they can with o rings and then clean it up in post. No right answer.​
    Gary
     
  17. Steve Maller

    Steve Maller UAV Grief Counselor

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    Dave, my props are fine, and the copter's really smooth. That's not what this is about.

    It's amazing...nobody seems to understand what i'm asking. I imagine that's my bad. Let me see if i can explain better...

    Let's say i want to experiment with one of the Gyro settings to watch for changes in flight characteristics without having to jack up to MKTool each time. so in the Gyro-x field in MKTool, I fill it with "POTI-x" instead of typing 100 or whatever into that field in MK Tool.

    Now, how do i see what value that POTI-x has set Gyro-x to? Eventually, when i'm satisfied i've found the optimal value, i can change the value for Gyro-x from "POTI-x" to 99 (or whatever my blessed number is).

    Does all this make any sense? And this applies to any value in MK Tool (such as GPS, etc.).
     
  18. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Makes perfect sense, Steve. Rewriting in geekspeak: How do you map POTI values back to whatever MK-Tool field you've assigned to be controlled by a POTI so that, once you've tweaked via a POTI/RC channel, you can now just type in the right value (rather than a POTI number).

    I wish I knew the answer to that. It might be a question for Holger or Ingo in Germany unless someone already knows the answer.

    Andy.
     
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  19. Steve Maller

    Steve Maller UAV Grief Counselor

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    Hmm, actually, it looks like Holger wrote it all down here: http://www.mikrokopter.de/ucwiki/en/MKTools-Setup
    Search for "Setting GPS Parameters". Now if I can just figure out what he means my "Display-Menu". :confused:

    It's amazing how I read new things every time I go to those Wiki pages.
     
  20. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I think "Display Menu" just means the, for example, GPS window (if you've been using the POTI to control the value).

    Could it be that simple? You assign the GPS value (say), to a POTI....tweak the POTI, and then read the value back off the MK TOOL screen? It's worth a try, I suppose.

    Or did you already whip off your copter-beanie and try this Steve? ;)

    Andy.
     

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