Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: dellagd on April 29, 2009, 02:44:13 PM

Title: micro servos & motor controllers
Post by: dellagd on April 29, 2009, 02:44:13 PM

I'm looking for some good micro servos
how are these (they are for a small robotic arm)
http://www.raidentech.com/5gtorcse.html (http://www.raidentech.com/5gtorcse.html)

Title: Re: micro servos
Post by: galannthegreat on April 29, 2009, 04:22:39 PM

I see nothing wrong with the servos. And funny thing... I've been looking for some servos like these for a dirt cheap price like that :)

PS Post some pics/vids of your robo-arm progress ;D

Title: Re: micro servos
Post by: Razor Concepts on April 29, 2009, 05:32:07 PM

Don't buy from raidentech.

Get HXT900 from hobbycity.com

Title: Re: micro servos
Post by: dellagd on April 29, 2009, 06:03:52 PM

WOAH!
$4!

Title: Re: micro servos
Post by: Razor Concepts on April 29, 2009, 06:41:55 PM

They also have standard sized for $5 i believe, and super high torque metal geared servos for $8.

Only drawback is a long shipping time.

Title: Re: micro servos
Post by: galannthegreat on April 29, 2009, 07:08:47 PM

Wow, I though $8 was cheap :o, I must've been brain-washed by all of the hobby shop pricing.

And they take Paypal !!! ;D

Title: Re: micro servos
Post by: dellagd on April 29, 2009, 07:25:28 PM

how do they sell for that cheap? this is great!
and since I will be getting a used R/C tx/rx I will make a R/C remote controlled arm!
how long is long shipping? (if I bought the shipped from us ones)
and here, take another helpful point.

Title: Re: micro servos
Post by: Razor Concepts on April 29, 2009, 07:56:12 PM

shipped from us should be about a week. From overseas is is 2 to 3 weeks.

Title: Re: micro servos
Post by: Indiana_Geoff on April 29, 2009, 09:17:16 PM

I have used GWS micro servos in RC planes quite a bit.  Very inexpensive and they have not failed me.

Title: Re: micro servos
Post by: dellagd on April 30, 2009, 06:28:12 AM

thought I might ask this too, would this work for a robot with 12v motors (the one you find at radioshack)
http://cgi.ebay.com/New-R-c-Plane-RC-25A-Brushed-Motor-Speed-Controller-ESC_W0QQitemZ260386237147QQcmdZViewItemQQptZRadio_Control_Parts_Accessories?hash=item260386237147&_trksid=p3286.m20.l1116 (http://cgi.ebay.com/New-R-c-Plane-RC-25A-Brushed-Motor-Speed-Controller-ESC_W0QQitemZ260386237147QQcmdZViewItemQQptZRadio_Control_Parts_Accessories?hash=item260386237147&_trksid=p3286.m20.l1116)
it is really cheap and I really want a motor controller.

Title: Re: micro servos & motor controllers
Post by: Razor Concepts on April 30, 2009, 06:51:27 AM

No, airplane ESCs are designed for something with no stall current (since all they are doing is spinning a propeller). A robot has high stall current when you first start moving so the ESC will fry there.

Title: Re: micro servos & motor controllers
Post by: dellagd on April 30, 2009, 01:50:56 PM

well then u have any suddgestions?

Title: Re: micro servos & motor controllers
Post by: dellagd on April 30, 2009, 02:05:11 PM

how about this one
http://cgi.ebay.com/Motor-Speed-controller-240A-Brushed-ESC-for-Model-car_W0QQitemZ290313426108QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item290313426108&_trksid=p3286.c0.m14&_trkparms=72%3A1205 (http://cgi.ebay.com/Motor-Speed-controller-240A-Brushed-ESC-for-Model-car_W0QQitemZ290313426108QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item290313426108&_trksid=p3286.c0.m14&_trkparms=72%3A1205)|66%3A4|65%3A12|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A200

Title: Re: micro servos & motor controllers
Post by: galannthegreat on April 30, 2009, 02:05:36 PM

Something along these lines would work nicely:
http://www.solarbotics.com/cad/products/k_cmd/ (http://www.solarbotics.com/cad/products/k_cmd/)

Also check Pololu, they have a good selection of controllers.

You can vary the speed of them via PWM

Title: Re: micro servos & motor controllers
Post by: dellagd on April 30, 2009, 07:19:02 PM

k cool

Title: Re: micro servos & motor controllers
Post by: Webbot on April 30, 2009, 07:56:52 PM

Sorry to keep 'banging on' but -  Solarbotics L298 and Pololu devices are supported by my library

Title: Re: micro servos & motor controllers
Post by: dellagd on May 01, 2009, 02:56:00 PM

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=3743&Product_Name=HXT_6.9kg_/_39.2g_/_.16sec_Twin_bearing_servo (http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=3743&Product_Name=HXT_6.9kg_/_39.2g_/_.16sec_Twin_bearing_servo)
what is the torque on this motor, and what is dead bandwith?

Title: Re: micro servos & motor controllers
Post by: galannthegreat on May 01, 2009, 03:15:53 PM

Dead bandwidth is pretty much an "irrational number" or something beyond the range, this means you won't be able to control the servo with that pulse width. For the torque, if you're talking about the HXT 900, is 1.6kg/cm.

Title: Re: micro servos & motor controllers
Post by: dellagd on May 01, 2009, 05:11:07 PM

no the servo I linked to (I know, I forgot to link to it, I pasted it above. I copyed the link to the clipboard but forgot to paste it  :P )

Title: Re: micro servos & motor controllers
Post by: galannthegreat on May 01, 2009, 06:35:24 PM

They give you stall torque there, 'bout 0.8kg/cm. Dead bandwidth should be pretty universal among analog servos, so it should be about the same.

Title: Re: micro servos & motor controllers
Post by: dellagd on May 01, 2009, 08:02:38 PM

k thanks

Title: Re: micro servos & motor controllers
Post by: Admin on May 07, 2009, 05:27:20 PM

I use the Futaba microservos. Look it up on the Futaba site.