3d scanning - today's hack

As I mentioned at the end of my last blog post, I want to scan some of the parts into 3D digital models.  

I'm making almost everything from scratch on the build, including the small tip inserts for the slats and flapperons.  Normally these come with a kit and are made of either fibreglass or more recently are blown plastic molds.  I could just purchase these, but Ron has originals from a 701 which shares the same sie and shape of the 750 ones.  Purchasing is easy but expensive and doesn't do anything for increasing my learning.  Making my own may not be much cheaper in the long run, but certainly equal or less and making my own also means I can learn some practical skills that come from 3D modelling and printing.

First step in this process is to 3D scan the original tips.  Again, I could just purchase a 3D scanner and get at it, but what fun would that be?

When Microsoft brought out the XBox gaming system, they shortly after released a sensor system that can detect player movements and translate that into interactive game play on the screen.  I believe this was in response to the Nintendo Wii game system which had already broke ground and was first to market with this type of player interface.  Microsoft took the best of what the Wii motion sensor did with infra-red (IR) and expanded it to include camera capable of sensing colour, faces and more refined depth of field.  Enter the "Kinect".

In this past decade of electronic and programming experimentation, it wasn't long until someone (much smarter than me I'm certain) said "Hey, I wonder if there is a way to hack this XBox sensor and piggyback on what Microsoft developed for other things?"  One of the first uses was for robotics control - robots that could see (sense) and recognize objects.  This quickly led to 3D scanning for types of objects, both for item manipulation and avoidance (is the obstacle in my way too big to move or is it of a shape I can grab/push etc.)

These type of developments often branch out to other things, including 3D printing.  Think about the possibilities!  Being able to 3D scan a rare car part and print a replacement for example.  Scanning and printing replacement bio-mechanical pieces (heart valves).  Printing materials are also evolving - industry is now printing everything from concrete to rubber to aerospace alloys.

Like 3D scanning, 3D printing has come also come to the home/hobbyist workshop - makes sense, these home hobbyist are often on the leading edge of these things, at least initially.  At thankfully for less knowledgeable people like me, they often share their knowledge online - thanks YouTube and Instructables.com!

So, where to get started.  I picked up an XBox 360 Kinect sensor.  It is the most current one being used by 3D scanning hobbyists and has wide ranging support.

 
The hack of the sensor requires 3 items.  A 12 Volt power adapter (bottom left and middle), the male end of a USB cable (top) and the Kinect sensor itself (cable end on the right).

Normally the XBox console gets power and sensor data directly from the Kinect.  As a result (and probably because Microsoft wants to control everything) the Kinect has a proprietary plug similar but not exactly like a USB end.  The third party 3D scanning software runs on a Windows computer, so that requires a USB connection.  So, my hack requires replacing the proprietary XBox connector with a USB and also injecting 12 Volt into the cable to replace the XBox console power.

​I found this wiring diagram in one of the online tutorial videos.  In this case, the author wanted to dual-purpose his Kinect sensor for 3D scanning and maintain it for gaming use.  To do so, he added a switch in his diagram - I won't be doing this, I don't intend on reusing this for XBox, so I can eliminate the switch and the XBox end shown on the left:

First step was to clip off the unneeded end of the USB cable (the phone end in the case of my sacrificial USB cable) then strip off the outer jacket of the clipped end:

Strip back the outer shielding if there is some and the inner foil shield if there is some (cheap cables don't have these, that's why they are cheap!):

Trim away the two shields, leaving the traditional white (data -), green (data +), red (5V +) and black (ground) USB wires:

 
Repeat the process with the Kinect cable (cut off the proprietary plug and strip/trim the shielding:

First thing I noticed once the shielding was pulled back was an extra brown wire I wasn't expecting....hmmm.... I was expecting a gray wire.  Wonder if the diagram is referring to the outer shield, it's kinda gray?

A little further reading in some of the comments on the YouTube videos and some of the instructables pages I quickly discovered that Mircosoft switched to a brown wire from gray at some point.  Problem solved.

I tinned the wires first after stripping of the insulation - this makes soldering them together much easier when the time comes.  I also added thin wall heat-shrink tubing to each connection which once I confirm everything is working, will be shrunk to tighten everything up.  Next, solder white to white, green to green, red to red.

Next, add in the 12 Volt supply lines.  Positive 12 Volt from the wall adapter to the brown wire (gray in the diagram).  Lastly, black wire from the USB side, black wire from the Kinect side and Negative 12 Volt from the wall adapter (hard to see in the picture sorry).

Next, connecting to a computer and powering it all up - hopefully no smoke escapes!  Unfortunately, my laptop doesn't have a graphics card that is supported by the 3D software, so I'll have to wait to get my home server back up and running to test this, but should be good!

Not much I like better than wiring projects, can't wait to do more of this on the airplane.

I'll file this in tools for now and get back to it soon.  Want to get the 3D scanner working so I can scan the flapperon and slat parts I mentioned above then print them.  Carbon fibre anyone?  :)

​Stay tuned.