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Great deal on a 3 axis gimbal with Alexmos controller

Posted by Gary McCray on June 26, 2015 at 4:00pm

Just had to tell all of you about this $59.95 three axis gimbal deal on EBay:

3689656824?profile=original

This seemed like a great deal and looks to be identical to DYS Gimbal on Hobbyking which is $200.00.

I got one and quality appears excellent though I haven't tried to use it yet (I will probably get another.) 

I'm planning on converting to a Storm 32 for a laser rangefinder scanner.

Apparently DSLRPros has moved on and is wholesaling them out.

http://www.ebay.com/itm/DSLRPros-3-Axis-Gimbal-for-the-GoPro-3-3-and-4-/161735430984?pt=LH_DefaultDomain_0&hash=item25a82ed348

I get nothing from anybody for this, but if you want a real 3 axis gimbal, this is the best deal you'll ever see.

Heres a link to the manual for the DYS: http://www.getfpv.com/media/wysiwyg/documentation/3AxisbrushlessGimbalManual.pdf

Heres a link to the Basecam (Alexmos) Home page: http://www.basecamelectronics.com/

And a link to download the appropriate 8bit Alexmos Gui: http://www.basecamelectronics.com/files/SimpleBGC_GUI_2_40b7.zip

And a link to download the Alexmos manual PDF file: http://www.basecamelectronics.com/files/v10/SimpleBGC_manual_2_4_eng.pdf

(This does include the Alexmos 3rd axis expansion board.

Best regards to you all,

Gary

Tags: 3, brushless, camera, gimbal, axis
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Comments

  • Gary McCray August 2, 2015 at 9:35am

    Hi Dan,

    Do you have yaw set to Invert?

    On mine, the yaw definitely needed to be set to Invert with pitch and roll set to Not Invert.

    And Chris,

    Using those settings, on mine yaw seems to be working correctly although it may need to be cranked up a bit in power or additional (+) power.

    Definitely it isn't glitchy. It doesn't twitch at all when sitting still or when moving.

    I did have a problem with pitch twitching, but that was solved with current settings.

    I am using a 2S battery and if you are using more cells, the power and + figures may need to be adjusted.

    Best,

    Gary

  • Dan Murray August 2, 2015 at 9:27am

    Hey guys,

    Here's a video of the issue I'm having with yaw. Seems to me like the control is reversed, as the error builds exponentially...seems like it thinks it is correct in the opposite direction. Any ideas?

  • Chris July 31, 2015 at 11:43pm

    i set it up with your settings, but it went back to how it was when i first got it, the Yaw is glitchy, it keeps jerking like if someone is turning the power on and off every second or two.

    heres a video of it https://www.youtube.com/watch?v=jatdwSd6no4

  • Gary McCray July 26, 2015 at 6:52pm

    Hi Chris and Euan,

    Chris, the P value at 1 seems a bit light for Yaw, since P is the primary portion of a PID it would reduce response amplitude / speed.

    And I do think the power figures are a bit high, perhaps more so for a 3 cell versus my 2 cell.

    Possibly decreasing the power but in some cases increasing the + factor could be a better solution.

    Primary "Power" (I understand) equals static holding (continuous) power versus "+" which equals temporary increase while moving power.

    Also has anybody tried the 6 way calibrate?

    (Damn hard to implement in the real world.)

    One of the reported symptoms of not doing that was the slow drift in yaw which I have also seen, but am not currently having a problem with.

    Interesting that when it is upside down there is Pitch changed to inverted which you would expect and Yaw changed to not inverted which you would also expect and roll not changed from not inverted which takes a minute to figure out but which also seems right.

    I do wonder a bit that possibly the gimbal itself, although balance-able upside down might still not function optimally because of the increased off angle weighting.

    (I want to turn mine upside down too, but will be interested to see how yours works out).

    Interesting also it took so long to turn 45 degrees with your limit set to 5 degrees per second it should take 9 seconds at maximum rate.

    Mine is actually working pretty well right now, but I know the PIDs are going to need to be tweaked for maximum performance and power probably isn't totally optimal for me yet either, (I need a fast manual move rate for scanning).

    Best Regards,

    Gary

  • Chris July 26, 2015 at 1:31pm
    I have it setup upside down right now for testing here is a quick video I took, this was before messing with yaw follow or the joystick
    http://youtu.be/oorI04MOG30
  • Euan Ramsay July 26, 2015 at 1:19pm

    Chris, did you not have to set AXIS RIGHT to -Y, so pitch was listed correctly?

  • Euan Ramsay July 26, 2015 at 1:09pm

    I get a very, very slow drift in yaw on mine. I had to bump power to 160, and Yaw D rate to 20. Apart from that...I just need a window to go test time.

  • Chris July 26, 2015 at 1:08pm
    This is my last settings I believe worked, I need to verify but it's the last screen shot I had in my pile
    http://i.imgur.com/OMZ9dPS.jpg
  • Chris July 26, 2015 at 1:03pm
    Hey Gary thanks for all the info, I was trying with this setup for a while before I got anything to work, it would hold in place but twitch every second or two. It doesn't work on USB for me but I figured that, USB only pulls 5V and maybe 1-2 amps max. Even on USB 3.0 it's not enough, I plugged mine into a 3S 1300 and tied it to one of thos scorpion camera mounts just for testing until I can get it working, I had no luck at all until I blanked all settings to 0 and increased them one by one using a tutorial I found but lost now. But I got it working pretty well as a handheld but it was locked in one direction that is set when you boot it and if you move it too fast or jerk it at all it freaks out and spins like 180 almost.

    Not content on th locked angle I went to setup it for a follow mode where when I yaw turned the handle it would follow the yaw, that worked pretty well but it was a bit slow, if i turned about 45 degrees it would take maybe 30 seconds to catch up and then it wouldn't stop once it got that spot it just kept spinning.

    I then bought a sainsmart joystick and Hooked it up to help simulate using my Tx to yaw and pitch the camera but once I set I all up it would pitch but not yaw, and if I flipped the wires it would yaw and not pitch, that's as far as I got because I noticed the motors getting really hot and I shut it down in fear of burning out the motors, I haven't got a chance to get back to it but I believe my settings for power were 200 with +- 10 so I should probably pull it back and try your settings. I'll boot up my desktop and check what my settings were so I can post them

    - Chris
  • Gary McCray July 25, 2015 at 6:53pm

    Hi Dan Further Work with results as followed.

    Input recommended starting settings from DYS Gimbal PDF page 9 of 9

    I set PIDs, Power, Invert pitch and yaw as shown and changed from 14 poles to 22 poles and unchecked skip gyro calibration at startup and wrote it.

    Still problems and not right and yaw definitely not right so please see below, actually got things working pretty well.

    First you need to do setup with both battery and USB connected (I am using a 7.4 volt battery so not sure about bigger ones).

    OK

    Num Poles = 14

    Roll P 13, I .2, D 17, power 110, +0, not invert

    Pitch P 12, I .11, D 9, power 100, +25, not invert

    Yaw P 18, I .23, D 17 power 130 +25 INVERT

    Try this, it seems to be working pretty well for me now doing setup with battery and USB connected.

    Auto Motor Configuration doesn't work worth ####.

    But I set power and invert values based on actual behavior until achieved apparent decent operation.

    At least it's a place to start.

    Pretty clear these are 14 pole motors though by looking at spread from auto (13, 15 and 16)  and not 22 pole motors as mentioned in the DYS PDF manual.

    Actually looking to be working pretty well now - including default yaw behavior.

    Best Regards,

    Gary

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