Robotics: Pigbot - Err...or another look at my first UGV
Posted on 2012-07-11 @ 12:20:10 by r00t - Read the parent: Homemade UGV/ROV Pan-Tilt Mechanism in Action!

My first adventure into the world of unmanned ground vehicles (UGV) began here, with this ugly beast, which I affectionately named "Pigbot":

Pigbot Today (07.11.2012)
Questions or Comments?

I never took it any further, but it does showcase the creation of my first (and so far only) homebrew pan/tilt camera camera mount. A reader recently contacted me asking for some more information about the design of it, so I took some more pictures...

You can find all the pictures in a ZIP file attachment (below), but here is a close-up of the pan-tilt servo and camera:

As you can see, it is very simple:

  1. The servo that pans the camera is mounted to the lid of a plastic jar. I simply cut a hole in the lid and drilled some holes for the screws to mount the servo sercurely to it.
  2. I then created a U-shaped bracket (from a bit of sheet aluminum) to hold the servo that tilts the camera.
  3. I attached this bracket via screws to the servo control horn of the panning servo.
  4. The tilt servo was then fitted to the bracket, and secured with a small zip-tie.
  5. I then fashioned a bracket to mount the camera to the tilt servo's control horn.

This bracket was also made out of the same sheet aluminum that the U-shaped bracket holding the tilt servo was made from. It consists of two parts:

These pieces, after being fashioned, were bonded together using 2-part epoxy (specifically an epoxy called J-B Weld - I love this stuff!) to form a single bracket. Once cured, the camera was secured to the bracket with a couple of screws (the original bracket for the camera had a similar mounting method; I didn't have to modify the camera), and the bracket was attached with screws to the tilt servo.

I used aluminum to form the brackets because it is fairly easy to work with, and it was lightweight (my goal original was to keep the weight down on the robot to improve battery usage). You could, however, make the mount out of steel. The camera bracket could then be spot welded, brazed, or soldered instead of epoxied; it would also be possible to rivet it together if you wanted to take the time for that.

Back when I originally constructed this pan-tilt bracket and servo system, there weren't many options available to purchase ready-made brackets, and what did exist wasn't very cheap at the time. Typically when I build things I always try to take the most inexpensive route, and that usually results in homemade components, unless an off-the-shelf (OTS) solution is readily available and is much cheaper than what I feel my time is worth. It also depends on whether I feel that what I am doing can be a learning experience; if it is, then I may pursue it even if a cheaper OTS option is available.

I hope this gives you a better understanding of how the pan-tilt mechanism of this robot was constructed. I have recently given some thought toward expanding this robot by making it wifi capable using an old Linksys WRT54G router and a copy of OpenWrt, coupled to an Arduino for control of the motors. We'll see what happens in the future. Until then, enjoy the pictures, and be sure to download and check out the images in the attached archive below!

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Questions or Comments?

If you have any questions or comments about this article, please contact me...

pigbot-07112012.zipMore pictures of the Pigbot pan-tilt mechanism 536.00 Kb
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