Comments on: Life-Size Katamari Lives

By: Ball Transfers

Ball Transfers — Tue, 23 Feb 2010 14:14:19 +0000

This is extremely well engineered. I wish you the best of luck with your project and hope you push it further!

By: Steve

Steve — Thu, 21 Jan 2010 17:10:36 +0000

I am very interested in Tim and Eves comments. Before I even saw this video, I was building a giant trackball for my daughter who has Cerebral Palsy and none of the ‘adaptive’ equipment out there seemed to work, because they all call for some type of fine motor control. So I decided to build one. Prototype #4 just became operational yesterday. I am using a 6 lb. bowling ball as the ball (sanded with 400 grit sandpaper to give it a matte finish and read better with the laser), a standard laser USB mouse mounted underneath the ball, and a software package (demo) called PointSmart to reverse the vertical movement and slow down the tracking speed. The real problem that I am having is the mounting mechanism for the bowling ball. My first prototype was using a bearing tripod similar to what is shown on the video, but with a nylon roller ball and a nylon cup thinking that (similar to a comment above) that nylon should contain the noise and provide nice smooth movement. Turns out that there wasn’t enough friction between the ball and the nylon to actually turn the bearings so the ball just slid, but not very smoothly. Prototype #2 used three stainless steel roller rods (similar to an actual arcade trackball) but I ended up with the same problem in reverse, there was too much friction between the bowling ball and the stainless rods. Prototype #3 used nylon slides, no bearings at all-utter failure. Prototype #4 is using almost exactly what is shown on the video, a 1″ spherical stainless steel bearing tripod (these units are actually called ‘Ball Transfers’ if you try to look them up on the internet). They do provide the ease of movement that I am looking for, but are very noisy. The noise actually doesn’t come from the contact of the trackball and the bearing, but from the internal mechanics of the bearings themselves. Each of those 1″ stainless spheres that the bowling ball sits on in turn sits on a dozens of smaller bearings, allowing the 1″ ball to turn freely. It is the 1″ bearing turning against all of these little bearings that provides all the unwanted noise. They also do run a bit rough, since they are quite cheap.
The other thing that I did was wire in 1/8″ stereo jack into the left mouse click button and built a giant pushbutton as the mouse click. So instead of trying to fiddle with a small mouse button, my daughter can just mash the big button when she needs to click.

Next steps: I am finally going to shell out the cash for a set of precision ‘clean room’ type bearings used in precision medical equipment or similar. They tend to run about $30 each, so you can see why I have tried everything else first, but that should finally provide the smoothest movement, and cut down the noise.

Sorry for the long post, just interested, thanks.

By: Techni

Techni — Tue, 19 Jan 2010 08:10:45 +0000

Could you provide the wiring/coding needed to make a PS3 version?

I ask this because you would be able to eliminate the PS2 controller altogether and just have the microcontroller report itself as an HID compliant controller to the PS3.

By: Kellbot

Kellbot — Fri, 02 Oct 2009 05:32:47 +0000

@cristi Yes, you can power it from any +5V power source.

By: Cris2000

Cris2000 — Sat, 05 Sep 2009 16:22:34 +0000

Hi !

I would like to ask you if there is a schematic for connecting a mouse to an analog potentiometer without the Arduino schematic.

By: cristi

cristi — Thu, 03 Sep 2009 23:57:05 +0000

can you power the AD5204 without the arduino ? nice blog

By: DeadlyDad

DeadlyDad — Sun, 16 Aug 2009 21:45:58 +0000

Hmmmmm….. How to use a giant, soft, rubber ball…..

Well, one option that springs to mind is to use a large ‘cup’ to hold it, lined with something like strips of UHMW polyethylene to reduce friction. Another (geekier) option would be to pierce the cup with hundreds of small holes and levitate the ball with air, a la air hockey. You could have a smaller, solid rubber ball sitting in a hole in the middle that would work like your metal one. There would be plenty of rubber-on-rubber friction to make sure that the yoga ball movements were accurately represented.

By: Eva.

Eva. — Thu, 23 Jul 2009 17:56:08 +0000

Kellbot, go to Fark’s photoshop project and photoshop your tinysaurs! Check it out to see what I mean: http://www.fark.com/cgi/comments.pl?IDLink=4519758

By: Mia

Mia — Sat, 11 Jul 2009 00:07:41 +0000

Brilliant stuff Kell! Bravo!

By: Kellbot

Kellbot — Fri, 03 Jul 2009 14:25:21 +0000

Hi Cindy,

I started with an arduino – http://www.arduino.cc – there are a bunch of tutorials on the Arduino site which make it a good jumping off point.