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Gina

Canon DSLR debayered with added cooling, filter wheel and OAG in one unit

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This thread will continue from where the other thread "1100D debayered with added cooling, filter wheel and OAG in one unit" left off.  I have failed in my attempts to remove the cover glass and debayer 1100D sensors so I'm trying other model viz 450D and 1000D.  Since ATM I don't know which of these models will succeed, I'm leaving the specific model number out of the title of this thread.

Edited by Gina

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Here is the latest cross-sectional diagram for this project.  This shows a Lodestar guide camera.  Not to scale.

post-13131-0-75154000-1401918119_thumb.p

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i had an old russian monocular (an MN20x60) that has (according to some blurb i found) the prism section sealed with a ruby coated optical window to keep dust out of the prism section. do you think this could be suitable for an optical window for the dry zone? it isn't mentioned on this page, but it's definitely coated.

http://www.monocular.info/mn12x20x.htm

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It might be if it's big enough to cover the image frame size.  You want an IR filter somewhere in the light path but you can keep the IR filter in the camera, just removing the blue coloured filter.  That seems to be sufficient.

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Dimensions of carousel

  1. No. of filter positions - 4
  2. OD - 100mm
  3. Centre hole - 10mm
  4. Thickness - 3mm
  5. Filter size - 36mm (unmounted)
  6. Filter thickness - 2mm (to suit Baader filters)

Dimensions of carousel timing pulley (aluminium)

  1. Teeth - 24
  2. Flange OD - 20mm
  3. Boss OD - 10mm
  4. Overall height - 18mm
  5. Flange height - 11mm
  6. Boss height - 7mm
  7. Bore - 3mm

Dimensions of motor timing pulley (plastic)

  1. Teeth - 24
  2. Flange OD - 19.8mm
  3. Hub OD - 12.7mm (1/2")
  4. Overall height - 17.46mm
  5. Flange height - 11mm
  6. Hub height - 6mm
  7. Bore - 4.76mm (3/16")  (tight fit on stepper motor output shaft)

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Here is an update to the cross-section diagram.  The FW carousel is mounted on the hub of the aluminium timing pulley.  This runs freely on a 3mm axle which is a tight fit in the printed boss.  The latter is glued to the underside of the separator plate (the part that separates the dry box and FW).  The separator plate now has a 11mm hole to clear the hub of the pulley.  This puts the carousel at the right height without having to turn down the pulley. 

Gluing the boss on has also meant that the separator plate and FW casing can be printed as one item.  The top plate for the FW will also be printed from PLA with hollows to clear pulleys and belt.  It will also be shaped to act as the top side of the rectangular hole that will take the OAG.

The OAG will have a rectangular section that goes into the FW casing with extended sides shaped at 45 degrees to which the surface silvered mirror will be glued.  At the other end (the outside) the OAG will have a cylindrical section whose ID will be a snug fit for the Lodestar guide camera.

post-13131-0-37642000-1402143996_thumb.p

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Now I have a working 3D printer (UP Plus 2) I have been able to get back to this project :)  This is a lot smaller than the Velleman and much better for detail and accuracy (even when it did work) so has resulted in some design changes to the camera case parts.

Here are some photos of test prints printed with the reel of filament that came with the printer, which was white.  Final prints will be in black.

post-13131-0-11062900-1405242629_thumb.jpost-13131-0-56694800-1405242631_thumb.jpost-13131-0-73504800-1405242634_thumb.j

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One idea that could be a possibility with the greater resolution and accuracy of the UP is to use printed spur gears to drive the carousel rather than timing belt and pulleys.

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The simplest option would be to have teeth on the outside of the carousel and the motor could be 25mm diameter, which is a quarter the size of the carousel, giving a stepdown ratio of 4:1.  This means that at full speed of the stepper motor I'm using it would take 10s to go from one filter to the next and 20s in the worst case to go from one filter to any other.  Considering I would be using at least a minute per exposure, I think this would be acceptable.

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Here's a screenshot of the SketchUp model of a carousel with 100 teeth.  This isn't the final version but for a 3D printer test.  I have holes for position detection to add and also I'll probably use a ball bearing for mounting it, so a larger hole in the centre.

post-13131-0-97232600-1405253115_thumb.j

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looking good  :grin:

i really like the look of this 3d printer

http://seemecnc.com/products/orion-delta-3d-printer

$1374, just really gets my back up that us UK people end up getting shafted pricewise... the uk distributor charges almost as much in pounds as the dollar list price so here it ends up at over $2100 at current exchange rates.

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Carousel dimensions :-

  • Pitch diameter - 100mm
  • No. of teeth - 100
  • Thickness - 3mm
  • Bore - to be decided
  • Filter hole OD - 36.2
  • Filter hole - ID - 34.2
  • Filter hole centre pitch circle radius - 28mm (reduced by 2 from previous versions)

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looking good  :grin:

i really like the look of this 3d printer

http://seemecnc.com/products/orion-delta-3d-printer

$1374, just really gets my back up that us UK people end up getting shafted pricewise... the uk distributor charges almost as much in pounds as the dollar list price so here it ends up at over $2100 at current exchange rates.

Thank you :)

Yes, I saw that one in my Google search.  Though it looked rather odd :D

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Missed a detail from the carousel data - filter thickness is 2mm.

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Going over to the UP 3D printer with it's different print model requirements has resulted in a complete rethink of the design of the casing for the camera and filter wheel.  Parts with a smaller base are needed due to the smaller print bed and the ability to print fine detail has opened up previously unobtainable possibilities.  As shown above this fine detail makes using spur gears a good option.

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Here are some modified designs to better match the UP Plus 2 3D printer.  These are screenshots from the SketchUp models from various angles.

I have reduced the size and removed the lugs from the dry chamber casing.  This will now be attached to the separator plate (and FW casing) at the top with an overlapping joint.  Note:- I haven't added the attachment holes as yet, or holes for cables.

post-13131-0-86116600-1405527152_thumb.jpost-13131-0-30961400-1405527154_thumb.j

The filter wheel casing has also been reduced in size and skirt added to attach to the dry chamber.  Also changed in shape to allow for the spur gear drive rather than timing belt.  Instead of a hole and boss to take the axle for thre carousel, I've added a printed post as axle with the carousel running directly on it.  The three small holes in a row take the phototransistors for the optical position sensing.

post-13131-0-26742700-1405527156_thumb.jpost-13131-0-87222300-1405527157_thumb.j

As already mentioned the carousel has been changed to spur gear drive on the edge and running directly on a printed post on the FW casing.  I've also added the optical sensing holes.  Here we have the carousel and stepper motor pinion.

post-13131-0-40023900-1405527516_thumb.jpost-13131-0-25397100-1405528120_thumb.j

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Filter wheel with carousel, stepper motor and pinion.  The carousel runs directly on a printed axle integral with the FW casing.  The filter wheel casing will be printed in black for the final product.

post-13131-0-37288700-1405898216_thumb.jpost-13131-0-64704800-1405898906_thumb.jpost-13131-0-20149100-1405898912_thumb.j

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Nor me Luis :p   I'm working on it :D

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I printed the dry box today - did it in sections.  I'll post photos tomorrow.

Edited by Gina

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Photos of prints of various parts...

These are the parts of the dry box, printed and assembled then attached to the filter wheel.

post-13131-0-39631900-1406066315_thumb.jpost-13131-0-93379200-1406066316_thumb.jpost-13131-0-12556000-1406066318_thumb.jpost-13131-0-21002800-1406066369_thumb.jpost-13131-0-86319500-1406066375_thumb.jpost-13131-0-12833700-1406066380_thumb.jpost-13131-0-36937000-1406066416_thumb.jpost-13131-0-53032900-1406066422_thumb.jpost-13131-0-52994000-1406066427_thumb.j

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A new print of the FW casing with extra parts and in black.  I've also printed the bracket that takes the IR LEDs that provide the optical position sensing for the carousel.

post-13131-0-34448100-1406066791_thumb.jpost-13131-0-37906800-1406066800_thumb.jpost-13131-0-36794000-1406066804_thumb.jpost-13131-0-39678200-1406066808_thumb.jpost-13131-0-56121800-1406066813_thumb.j

post-13131-0-89654700-1406066818_thumb.j

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Still to be designed and printed are the top of the FW casing and the casing that will go on the dry box and FW casings to contain the electronics.  I shall also be looking into the adjustment of the camera within the dry box, to align the sensor perpendicular to the optical axis.  I do have some ideas for that.  Then there's the access door for the silica gel.  Still a lot to do :D

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I have changed the design of the dry box to allow for an inspection cover to allow changing the desiccant or repairs should these be required.  Now I have the full print area available again on the UP Plus 2 printer, I can print the box as one part rather than three.

Here's screenshot of new design, the new box and it fitted onto the filter wheel casing.

post-13131-0-03045500-1406236948_thumb.jpost-13131-0-90806200-1406236951_thumb.jpost-13131-0-37673200-1406236961_thumb.j

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