Thursday, December 3, 2015

Building the DSLR CableCam non-demountable

This Blog post is one of an entire series
Motivation and Design
Download Link for CAD drawings (updated regular)
Bill of Materials
Motor and ESC considerations
CableCam rope
Building the DSLR CableCam
CableCam controller board
In order to simplify manufacturing, we came up with a couple of changes. Most important, the cablecam does no longer consist of three pieces - two arms plus centerpiece - but just one. And some modifications on the gimbal plate have been made.
All of these changes impact manufacturing only. If you find it more appealing being able to demount it into three pieces for easier transportation, feel free to use the previous version instead. The drawing contains both at the same standard.

Bill of Materials found here.


Step 1 - Backside

First all 25mm distance nuts are screwed into the back side plate including the two M5 ones for the running wheels. It does not matter at which side as the pieces are symmetrical. But you might want to check both plates if they have a better surface on one side or the other.


Step 2 - Drive shaft

The drive unit consist of one ball bearing with a collar and two aluminium pieces to hold the bearing's collar between them. Press the bearing into the first piece as shown below, the left part.

This is then forced into the back side plane from the other side of the cablecam, opposite the distance nuts.




To hold the bearing in place, put the 4 M3x16 screws from the inside(!) into the holes.

Add the outer collar plate and tighten all with 4 washers and stop nuts.




Put the d6x3mm washer onto the drive shaft and push it all into the ball bearing.

Secure the drive shaft from the other side with the shaft lock.


Next step is to mount the motor and the pulley into the other side plate.


And before screwing both side plates together, add the timing belt.

Then push the plate through the drive drive dog into the second ball bearing on the rive shaft.

This is how it all comes together. On the left side the collar bearing is held in axial direction, on the right hand side the bearing is fixed on the drive shaft but can move in axial direction if needed.

Put the M3x16mm stud screws into the 5 distance nuts at the end of each arm.

And mount the M3x30 distance nuts there.


On the bottom side, next to the running wheels, add one M3x10 one each side. The other right next to it will remain without a screw.

The gimbal mounting plate comes next. This block consists of 5 M3x45 screws and 5 d3x25 tubes plus the 2 8mm thick aluminium pieces. When assembling, watchout the direction and what is upside. The large plate goes under the motor. And the wholes in both pieces are not in the middle but slightly off center. This should ensure the cablecam frame does not get into the way.


Here you can see the plates are above the cablecam frame side plates.

The battery holder is built using the two X pieces, 2 M3x10 and 2 M3x16 screws, 2 M3x45 screws on 2 distance nuts.





The running wheel has the ball bearings mounted and using 2 washers on the inner side the wheel has the same distance from the frame as the drive wheel will have, hence the rope will be in one line.



The two cages are to be assembled next with 5 M3x10 screws and 1 M3x40 for each. The M3x40 only use is to make sure the cable cam can never fall off the rope, even if it flips. So when putting it on the rope you will first remove those two screws, set it on the rope and then add those screws again as safety measure.




Now it is time to add the remaining 21 M3x10 screws to give the frame its stability. In case the battery holder was not used on one or even both sides, add 2 of these screws in addition for each.

The drive wheel is added again with its 4 M3x25mm screws and 4 washers.



Depending on what ESC you are using, you can mount the ESC onto the frame directly. The SkyRC TS160 ESC requires 4 M2.5x10 screws and the required holes have been added to the frame already.








Thursday, February 19, 2015

Cablecam rope considerations

This Blog post is one of an entire series
Motivation and Design
Download Link for CAD drawings (updated regular)
Bill of Materials
Motor and ESC considerations
CableCam rope
Building the DSLR CableCam
CableCam controller board

Rope to use

Initially we discussed various options, steel cables, different types of ropes and at the end after some trial and error the conclusion was, a Dyneema rope with sheath is what we need. It is strong and yet lightweight. Its surface allows for smooth driving without much vibrations. Most important: Its prolongation under load is under 5%.
But it is very expensive.

The best rope currently is this one

The 6mm rope has 2500daN maximum load, it should be used with no more than 60% of that, which is 1500daN or about 1.5tons.

Forces

The formula to calculate the rope force is shown here

Let's try a simple calculation.

The distance to cover is l=100m. The weight of our cablecam is p=3kg. The tolerated maximum slack when in the middle is f=1m.

sqrt( (3/2)² + (3*100/ (4*1)² ) = sqrt ( 1.5² + 75² ) = 75kg

CableCam Controller Board

Content of this blog post moved to github together with the source code.

https://github.com/wernerdaehn/CC3D-CableCam-Controller





Building the GoPro CableCam - Part 4 - Final Assembly

This Blog post is one of an entire series
Motivation and Design
Download Link for CAD drawings (updated regular)
Motor and ESC considerations
CableCam rope
DSLR CableCam - Bill of Material
DSLR CableCam - Assembly of the two arms
DSLR CableCam - Assembly of the main body
DSLR CableCam - Final assembly
GoPro CableCam - Bill of Material
GoPro CableCam - Assembly of the upper body
GoPro CableCam - Assembly of the lower body
GoPro CableCam - Final assembly
CableCam controller board

Final assembly

To connect the two parts two lock pins d6 50mm (or slightly longer) with extra safety is used.
When connecting the two, the battery holder is on one side, the motor on the other side to balance the CableCam.



The lower body has four holes for mounting a regular sized brushless gimbal control board already and the gimbal itself has to be adapted to the center plate at the bottom.






Building the GoPro CableCam - Part 3 - Lower Body

This Blog post is one of an entire series
Motivation and Design
Download Link for CAD drawings (updated regular)
Motor and ESC considerations
CableCam rope
DSLR CableCam - Bill of Material
DSLR CableCam - Assembly of the two arms
DSLR CableCam - Assembly of the main body
DSLR CableCam - Final assembly
GoPro CableCam - Bill of Material
GoPro CableCam - Assembly of the upper body
GoPro CableCam - Assembly of the lower body
GoPro CableCam - Final assembly
CableCam controller board

The lower body

We start with the CC3D controller board, as this is mounted with the screws on the inside of the body, board is outside. Two times four M3x6 screws and 4 plastic distance nuts M3x6 are used for that.




The SkyRC TS120 ESC will be inside the body, the two pockets are used for the motor cable and the on/off switch.
(You should solder the cables first)


Then eight 30mm distance nuts are mounted with M3x10 screws.


And the other plate attached using another eight M3x10 screws.


With this we are done, all that is left is the motor with its drive dog and wheel.