360 Servo pendulum mount. Part 2: the pendulum

The pendulum has 3 parts.

  • pivot bar
  • semi rigid joint
  • Rig attachment

Construction is of stock section ( what I can get hold of at the local DIY/ have lurking in the dark corners of the shed) aluminium.

The pivot bar requires a method of fixing to the kite line and a method of limiting the turning of the rig. I intend to use this rig out of my courier bag so the dimensions are determined by what will fit without grief.

Pivot bar-1The semi rigid joint protects the fixings from snapping under shock by absorbing excess movement. At some point launch and recovery will end up with the rig grabbed and tugged about no matter how careful I am. The joint is from 5mm ID tube, 5mm dia bar and theromo-plastic tubing for brake hoses. The tube is pushed over the end of  a 5mm bar, drilled through and riveted. I hammered over the rivet ends to give a good grip on the tube. The theromo-plastic tube can fail in very cold weather if stored folded over and yanked straight. Warming the tube under the armpit does the trick.

_DSC0007

The rig attachment is a simple pinned sleeve. Paranoia got the better of me and I strengthened the servo coupling. I opted for a box section for improved rigidity, I found I could bend the U section open far too easily once it had the lever of the pendulum attached. 3/4 x 3/4 x 1/16th section (for some reason ally stock is always in imperial units) was available. I cut a cube and drilled both centres together to keep a concentric axle. The cube needs to be just big enough for the m5 nut to turn.

OLYMPUS DIGITAL CAMERAI have dug out an old Samsung mobile ‘phone battery which at 2200mAh on 3.7v is a much better power source than the P3 9V+UBEC set up. The 9v battery only held up for about an hour and a half, the mobe batteries go for much longer.

  • Rig, with servos, switch and battery =120g
  • Pendulum= 40g
  • Camera=370g

IMG_0002The EP1 ( at 370g) is right on the limit of what the rig can carry on the servo alone. It is better suited to something like an Lx5 (which is 100g less). I built the rig around the EP1 as it has a wonderfully fast AF which, when coupled to the clickPanPro control should get a fast pano sweep. The pendulum should stabilise faster than a Picavet so the timing can be cranked up without having to allow for wobble.  Ideally I want to get the sweep down to about 30s so that I have a fighting chance of getting an auto-stitcher working.

We shall see..

B

About billboyheritagesurvey

Heritage worker
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One Response to 360 Servo pendulum mount. Part 2: the pendulum

  1. Pingback: Around the Archaeology Blog-o-sphere Digest #6 | Doug's Archaeology

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