Great deal on a 3 axis gimbal with Alexmos controller

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

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-an...

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/3AxisbrushlessGim...

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_en...

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

Best regards to you all,

Gary

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Comment by Gary McCray on 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

Comment by Chris on 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

Comment by Dan Murray on 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?

Comment by Gary McCray on 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

Comment by Dan Murray on August 2, 2015 at 9:43am

Ah, scratch that...it was what I suspected. I switched two of the yaw motor cables and we're in business.

Next question: any way to speed up the yaw follow? It works fine but waits a bit too long to catch up for my liking.

Comment by Dan Murray on August 2, 2015 at 9:44am

Oops, didn't even see your post Gary - looks like you were right - I completely missed the option to invert in the software, probably would have been easier than switching the cables.

Comment by Euan Ramsay on August 5, 2015 at 1:20am

Btw guys, this is my first run with this gimbal. Completely factory settings. The results leave a lot to be desired.

Comment by Gary McCray on August 5, 2015 at 11:20am

Hi Euan,

I pretty quickly came to the conclusion that factory settings are not really workable.

The power and + settings really need to be modified. - (increased).

Probably higher power or + on the yaw will fix the yaw losing sync problem, I had that at lower settings on yaw and pitch.

And I know the PIDs need to be "tuned" to reduce the jitter.

Some of the effects looked like they might be more related to the camera too though.

I have my gimbal working pretty well statically as far as maintaining sync and low jitter for my laser rangefinder, but it can still benefit from more tuning.

Best,

Gary

Comment by Muhammad Al-Rawi on August 12, 2015 at 7:18pm

Hello all, 

I came across this under the files tab for the DYS gimbal on Hobbyking and plugged the values in. Here are the results with a GoPro (I don't actually own one, this is a loaner): 

It looks like a good start to me. The yaw is pretty swingy for hand held, but this may not be an issue in the air. 

The only axis I have inverted in the GUI is yaw. 

It does buzz a little bit. I can feel it too. It is very subtle when watching the realtime data tab. 

One behaviour I'm not too crazy about is this shaking/swinging on the yaw axis when pitched forward or backward more than ~45 degrees. I know it has functional limits, but is this normal? 

Comment by Shawn McCracken on August 15, 2015 at 10:53am

I have one of these I bought when I saw Gary post about it for sale. I mounted it and started tuning but I just don't have time to mess with it. $45 w/free shipping in US. PM me if interested.

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