Servo Control Questions

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rickymahk2013

Canada

Asked Sep 2015 — Edited Sep 2015

Resolved by Steve G!

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I have 2 problems about the servo angle control! Would any people can help to solve and answer it?

I have brought some servos. It spec. can rotate to 270 angle. But in the EZB programming, it just rotate to 180 or lower.
in some mini servos from (servo(D0, 40) and servo (D0, 160)) have a reaction. But when I set that lower than 40 or over 160, it will be no any action.

Thanks for any people help again!

;)

Ricky Ma

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Steve G

United Kingdom

#1 Sep 2015

Hi Ricky

Can you post links to the 270* and mini servos you are using with specs/data sheets. In regards to the 270 degree servo, the servo controls and script commands are for the mostly used 180 degree servos so you cannot get a servo to move past 180 as that is the set maximum. The only other servo control available in ARC is for the modified 360 degree (continuous rotation) servos.

What mini servos are you using,? Are they the micro servos from EZ Robot? I can't really answer the question about the mini servos unless we can see what they are and the specs for them. Maybe the min and max settings are set to 40 and 160 somewhere in your ARC project.

rickymahk2013

PRO

Canada

#2 Sep 2015

Thanks Steve,

First question, I'm understood! :)

Here is mini servo spec. for your review. Your meaning that I can set the min and max in range 40 and 160 only?

Steve G

United Kingdom

#3 Sep 2015

Thanks for the spec sheet, but it's still unclear to what the degrees of movement travel these mini servos have. Is it a 180 degree servo or more/less?

When I said about having min and max servo values set, without looking at your project, you might have a script specifying that you only want to move a servo in between 40 and 160, on you might have the min/max setting is a servo control set to these values. Can you post an actual link to the website where you got the mini servos? That migh help us clear things up a bit.

rickymahk2013

PRO

Canada

#4 Sep 2015

Hi Steve,

Here is the links, but this is in Chinese. Hopefully, you can understand! :)

http://world.taobao.com/item/43572934311.htm?spm=a312a.7700714.0.0.LR1eUM#detail

Steve G

United Kingdom

#5 Sep 2015

Thanks for the link. That helped.

From what I can understand about these servos, the 40*/one side pulse traveling 400us pretty much means that it is only an 80 or 90 degree servo, not a 180 degree servo, which would explane why you cannot get the full movement you were expecting. But apparently, inside of the servo, there is a little notches that can be filed down to get more travel movement out of these Corona servos. Also, extending the pulse can give a bit further travel.

So basicly, the mini servo you have will never travel lower than 40 or higher than 160 as you are experiencing.

Here's a couple of links you may find useful...

40 degree one side pulse traveling 400us

Corona DS238MG discussion