Saturday, April 15, 2017

Pan Tilt Feedback Control for a Bescor MP101 Video Motorized Pan Head


Tilt Feedback Control




So this first test works! Get a range of about 100 analog readings for the 30 degrees of tilt.

Hot glued the potentiometer directly to the head

On to Pan Control - what kind of analog potentiometers have multiple rotations - I want to stick with analog as I don't want to count pulses or worry about location on startup - hey these cheap 10-turn rotating ones might do it! Hope the gear size for 1:10 can be worked out.





I did a few quick test prints to workout the smallest gear teeth that would printout correctly.

Love first print designs that are 95% working!

This 1:10 ratio is going to work great for pan control!

More Analog Please
Lets try to get more range out of our analog potentiometer



This gear was a pain to design. I tried to work out how much gear was needed.

The top bracket ended up being too flexible and the gears don't stay connected - fail!





Inside gear and smaller B103 wheel potentiometer





Seeing full range of analog values with this 1:10 setup - but this small 10,000 Ω B103 is a fail!

Hot melt glue got inside the wheel while gluing on the gear - there's a small hole in the wheel and hot glue flows nicely into it as you press the gear on.

  potentiometer + hot glue = wheel doesn't turn

Tried a second time using tape to cover the small hole - it's still a fail!

Also See the not so nice tilt on the gear - these small pot's are easily damaged... This one turned into a 5,000 Ω.

Inside Gear it Is




A few issues with tilting:
 - arms a bit too long
 - arms a little bendy
 - alignment of top and bottom bracket












Control Center - found these cute joysticks for control - nice wiring...



And it's Done!

- The servo on top is for zoom control.
- The potentiometer holder still gets directly glued to head unit arm.
- If the glue doesn't hold - I've included holes to screw the holder directly into the arm. - Advantage of using the holder with the flipped potentiometer is that the gears are closer to the unit (keeping the gears aligned) and helps keep all the mess centered.
- Fixed: length and bendiest of tilt arms; added guide for alignment of top and bottom tilt bracket.
PAN
- Needed to add a cutout for the power feed into the camera.
- A wider camera would likely need a bit of a redesign with the top tilt bracket, add a spacer between to raise up the cam and change out the mounting screw or another option would be to print a drop-in replacement for the top plate. The existing plate is held in place with four screws.

TILT
- Once I thickened up the 10-Turn potentiometer base, had issues with screwing it into the base.
- The potentiometer uses a M8-0.75 thread.
- Not having that tap, completely destroyed one potentiometer trying to force it into the PLA holder.
- Now I heat up the PLA holder and busted up potentiometer threads and tap.
- The base still has enough flex to account for any misalignment's with the gears.

   
- Used existing screws from the unit. - These screws are long enough to hold the new printed part and existing bottom plate in place.
- The pan gear slips/presses onto the fixed pan/mount base.

Up NEXT
- Field testing
- Code Control
- Upgrades

References:

3d Parts and Design for above:
  Tilt Pan Position Feedback for Bescor MP101 Video Motorized Pan Head
  http://www.thingiverse.com/thing:2241863

my zoom control:
  http://pantonvich.blogspot.com/2016/07/canon-vixia-hf-r50r600-cam-recorder.html

parts:
  Bescor MP101 Video Motorized Pan Head
  http://smile.amazon.com/Bescor-MP101-Video-Motorized-Head/dp/B008T17W9O

  WXD3-13 10K Ohm 2W 4 mm Shaft Diameter 10-Turn Wire Wound Potentiometer
  https://smile.amazon.com/gp/product/B01CDXMC34

  Adafruit Panel Mount 10K potentiometer (Breadboard Friendly) (10K Linear) [ID:562]
  https://www.adafruit.com/product/562

  Dual-axis XY Joystick Module For Arduino Joystick Module
  https://smile.amazon.com/gp/product/B01D83B2G6

these parts didn't work out:
  B103 10K Ohm 5-Pin Dual Linear Dial Wheel Potentiometer
  https://www.amazon.com/gp/product/B013FPKCMM

additional:
  Cut your own gears with profile shift - OpenSCAD library
  http://www.thingiverse.com/thing:636119

  Bescor MP-101 Hack Part 1
  http://protechy.com/bescor-mp-101-hack-part-1/

  Bescor MP-101 and Arduino v3.0
  http://protechy.com/bescor-mp-101-and-arduino-v3-0/

  Hardware @ Lab
  http://hardware.ideaslab.mk/

  PJON - Arduino compatible Communications Bus System
  https://github.com/gioblu/PJON