Printer cartridge gears take to the air

The 19tooth gear sits nicely on a Towerpro MG90S spline with an m3 bolt. This is a 90 degree servo so it only served as dummy to get the mounting plate cut to size and test the alignment while I waited on the post… IMG_0139Poor fit to spline. After what seemed like an age (but was only a week) the 360 servo turned up….and its spline is very different from the MG version:IMG_0142I turned the gear upside down to get a clean fit, the locking screw is a self tapper so there is only one go at this. It slips. Needs a star washer. IMG_0143Slow circles. The Feetech 360 micro servo is sloooow.  I set clickPanPro to drive it a full circle for each move but it only turns about 45 degrees. This is geared down at 19/44 so the pan shift is about 20 degrees per step or 18 steps to the circle. With the delay at 6s per step it should take about 5 min 30s to complete a circle of 54 shots.

S95 raw frame limit. 266 raw frames fill the 4gB card, the write speed requires a wide time slice between shots (6s). 4gB is as much as CHDK can address on this camera without partitioning, (something I’m putting off for now – windows doesn’t see SD card partitions with out some hassle ). The card will fill in 26 minutes. This is not going to be a high speed set up! After 25mins I can swap in the EosM if conditions prevail.

Balance and switch position. The pan axle is offset to accommodate the EosM and make space for the USB connector on the S95. To get the horizon horizontal for both cameras the rig centre is 2.5cm from the camera centre:S95 balance pointsFinding the balance points is a fiddly business, James Gentles suggests balancing the camera axes on a pencil to find the centres and I did just that. The tilt axis is off centre as the EosM requires more critical balance than the S95 as it places a much heavier load on the servo. To get the balance I ended up moving as much as possible as far as possible to the left of centre, even the switch had to sit on the far left. Nervous of the fragility of the foundling gears I patiently waited for light wind, it was a long time coming and I grabbed a gap between fronts to catch an early morning rising breeze. IMG_0147The side view gives an idea of the tilt axis offset. The pendulum is cut down into 2 parts to fit in the A4 project box, in reducing the size of fixings I think the mounting post for this rig is now over-sized. It’s simply habit now to use an M6 based design. I’m considering adopting a version of Christian Becot’s ‘Filalu‘ suspension (on Christian’s suspension page, select ‘simple’ and there’s a link at the bottom of the page), the 8mm dia ally tubing has it’s place but I’m finding it a bit unwieldy for small rigs like this one: it’s tending to add stress to the M3 pan axle. With the Jones Rok aloft I waited for the wobbles of the light wind to subside and hitched the rig on the line…CRW_6882 IMG_6898 IMG_6899IMG_6839…and 270 frames of Cambridge were captured in 25 minutes.Unfortunately I’d got a dew drop on the lens during launch prep so I have cropped out the offending blur blob. These were shot with Walter Wings KAP-UAV CHDK script set at:

  • TV MIN=1/1000
  • Target TV= 1/2000
  • Tv Max =1/2000
  • Av Low= f2.8
  • Av Target= f4.0
  • Av Max= f8.0
  • ISO Min =200
  • ISO Max= 1 800
  • ISO Max2 =1250

IMG_0148 IMG_0150 Heavy metal. To get the space for the EosM I went for 30mm wide 2mm thick strip ally. It’s heavy stuff. Once bent it will stay bent. This is the 3rd version of this pattern I have built and I’m getting more confident in the design, it’s crude compared to Brooxes but, by being no bigger than it needs to be it’s tough. I’m hoping this will be a rig I can really hurl around! B

About billboyheritagesurvey

Heritage worker
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