HobbyKing.com New Products Flash Sale
Reply
Thread Tools
This thread is privately moderated by Jack Crossfire, who may elect to delete unwanted replies.
Old Nov 21, 2012, 03:39 AM
Registered User
Jack Crossfire's Avatar
Calif*
Joined Sep 2006
2,108 Posts
Discussion
The battle of the camera mount

So after all its calibration, the IMU on the camera mount was not accurate enough to improve camera pointing. Magnetic heading was always slightly off & required very precise calibration. It may have been magnetism from the servos. That led back to hacking into the servo pots.



The only way inside the winch servos was to desolder the motors. That revealed the pot was indeed exposed on the outside, but undetected due to a probing error. Those $50 winch servos have some beefy MOSFETs & a big motor. $50 buys a lot more than $10.

While staring at this $50 servo's crumbling lead free soldering with no conformal coating, it should be noted that it's no good for a mission critical aerospace application. The soldering is going to have tin whiskers.

The servos only use 1V of the full range of the pots. They leave a 1V buffer on each end. This seems to be because of the strange behavior of the pots. They don't have upper & lower stop points.

With no PWM, they can be manually spun beyond the maximum revolutions, using some kind of slip ring, then wherever they reverse direction becomes the new boundary. The servos have the 1V buffer to avoid changing their center points.

Of course, this means the center point changes depending on how the camera mount is rotated when it's off. The easiest solution is to put mechanical stoppers in the mount to stop it from rotating beyond the boundaries.
Jack Crossfire is online now Find More Posts by Jack Crossfire
RCG Plus Member
Last edited by Jack Crossfire; Nov 21, 2012 at 03:55 AM.
Reply With Quote
Sign up now
to remove ads between posts
Reply

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold 2-axis camera mount (MK HiSight) - including servos ed.ge Aircraft - Electric - Multirotor (FS/W) 2 Feb 27, 2012 03:38 PM
Wanted Xaircraft X650 quad frame and camera mount cryhavoc38 Aircraft - Electric - Multirotor (FS/W) 0 Feb 24, 2012 10:43 AM
Discussion Injection molded camera mount Joe Bennett Aerial Photography 3 Feb 23, 2012 09:43 AM
Sold Battle Tank Wireless Camera Platform mgroves FPV Equipment (FS/W) 0 Jan 23, 2011 06:09 PM
Discussion Destruction of Angusian IV Battle Fleet caught on camera Sprydle Life, The Universe, and Politics 9 Jan 09, 2009 03:18 PM