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Old Apr 12, 2012, 01:09 PM
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Gimbal Questions

Hi all; I posted these questions in the aerial photography forum and didn't get an answer so I figured I'd ask here too... I'm making my own camera gimbal cause I'm crazy and want it tightly incorporated into my new frame. To that end, I need to clear some things up.

I'm mostly interested in getting stable video so I'm most interested in using the gimbal for automatic stabilization. It seems to me this means I only need something like 45 degrees of movement in the two axis I'm interested in. Is this correct?

And if that is the case, why can't I use 180 degree capable servos and timing belt pulleys to reduce it down to 4:1 to keep my 45 degrees but use smaller (but faster) servos?

Is there a minimum response speed that's expected for something like this to work well?

Thanks in advance for any information or advice!

-Mike
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Old Apr 12, 2012, 03:03 PM
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you can..... my "askman" gimbal uses 2:1 belt reduction for this purpose.

I will let you know that you still need fast and strong servos that are true 12bit resolution to get smooth video.....

the best mount with crappy servos = crappy video I know from personal experience
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Old Apr 12, 2012, 04:52 PM
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So are the best servos digital coreless? Or something else? Not so interested in brand names as in style. What speed/power servo are you using. Thanks!

-Mike
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Old Apr 12, 2012, 05:16 PM
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I'm assuming digital coreless and based on the requirements of speed and power, it seems the ones used for helicopter tail rotors would be good choices. For instance, this one is very good:
http://www.hobbyking.com/hobbyking/s...sec_2_4kg.html

Am I on the right track with something like that?
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Old Apr 12, 2012, 07:46 PM
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I'm using this one on my DIY gimbal with good results. 12 bit resolution and lots of torque. http://www.completeheli.com/Align-RC...-Servo-K10425A
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Old Apr 12, 2012, 08:29 PM
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wow, that's a big and heavy servo.but seems pretty nice. What about the smaller Align servos like this one: http://www.servodatabase.com/servo/align/ds420
My gimbal design doesn't require a ton of torque as everything is balanced and with 2:1 reduction it's plenty strong already.

-Mike
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Old Apr 12, 2012, 09:50 PM
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i am using stardard sized servos and they putting out a lot of torque and really fast and I still get stuttering and wondering... with 2:1 reduction....

I think you will be surprised how much power and speed you will need
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Old Apr 12, 2012, 10:38 PM
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Stuttering and wandering doesn't necessarily mean the servo doesn't have enough torque. I'd also say that there is a massive difference in different servos of the same size. Brushless vs. coreless vs. digital vs. analog. The servo he linked can lift 10lbs at 1" which is very strong. To see the range, you can use http://www.servodatabase.com and put in a weight of at least 1oz and a max length of 1.5" which will get you into generally "standard-sized" servos. The power range will run from the mid 30 oz/in to the high 180 oz/in for the same basic size servos.

Anyways, not trying to argue, just trying to get a grip on what's working for people. What exact servos are you using?
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Old Apr 13, 2012, 12:29 AM
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Savox SC-1258TG @ 6.0v
http://www.amazon.com/gp/product/B00...00_i00_details

hyperion dh20x-scd and gcd version @ 7.4v
http://www.hyperion-world.com/produc...t/HP-DH20x-SCD

if the stuttering or twitchiness isnt from lack of power what would cause it? they are 12bit servos....
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Old Apr 13, 2012, 05:22 PM
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I tried the smaller ones. To move 550g with enough momentum, this was the minimum torque I needed. If you're just running a Hero, the smaller ones may work fine. Mine is a balanced setup but I have tightened down all of the pivot points so they offer a lot of resistance. This makes the servo work against the resistance to help eliminate the loose-goosey - just something I've done which gave me better video than bearings, hence the need for bigger servos.
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Old Apr 26, 2012, 03:55 AM
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Would like some clarity on what date the gimbal board will be available & what spec servos Hoverfly are recommending, i know it depends on the weight of your camera etc, but a general spec. Seems a few companies are in the race to produce a dedicated gimbal board, Picloc3X, HF & Photohigher, the world waits!!
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Old Apr 26, 2012, 09:44 AM
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Quote:
Originally Posted by squigg View Post
Would like some clarity on what date the gimbal board will be available & what spec servos Hoverfly are recommending, i know it depends on the weight of your camera etc, but a general spec. Seems a few companies are in the race to produce a dedicated gimbal board, Picloc3X, HF & Photohigher, the world waits!!
You should post this in it's own thread.
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Old Apr 27, 2012, 03:53 AM
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Would be good if HF could show us some videos of the gimbal board in action, we might be more persuaded to pre-order then, who would pay 360 without even seeing it in action??
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Old Apr 27, 2012, 08:46 AM
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And still the wrong thread
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Old Apr 27, 2012, 10:37 AM
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Quote:
Originally Posted by squigg View Post
Would be good if HF could show us some videos of the gimbal board in action, we might be more persuaded to pre-order then, who would pay 360 without even seeing it in action??

agreed!

Quote:
Originally Posted by webgeek View Post
And still the wrong thread
and agreed
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