Wednesday December 12 2018

Visible Light RTCS for Ball Movement using a WiiRemote

Video demo:

Quick Links:

BallControl Arduino Code
BallControl Processing GUI Code


To make this, all you need is the following:

  • Arduino UNO (preferably R3)
  • Motor Control Shield
  • 2 Stepper motors
    • I used the ones I found in some old optical drives I had laying around, here’s a pic of a smaller one I have not yet ‘harvested’
  • WiiRemote
    • Make sure to use a RVL-003 (the old one, not the new fancy MotionPlus stuff)
    • You can check out my old post here if you haven’t connected your WiiRemote to a PC yet: POST
    • Don’t forget to remove the visible light filter (you may need to buy a triangle screwdriver)
  • Large bright overhead lighting source
    • I used a fluorescent work-bench light with the magnifying glass removed
  • Laptop + Processing software
  • Balsa wood + black rigid-paper + black hockey-tape + packing-tape + very light and reflective plastic ball + Wires/Connectors + staples
  • Silicon Putty

Board Assembly:

  • Arrange the wood into a square frame                                    (held together by hockey tape).
  • Line the bottom with the hard black paper and use the packing tape to both affix the paper and put the entire thing under tension.
    • My finished board felt like a piece of a kit, it was kinda cool.  Balsa wood is amazingly light!
  • Use the hockey-tape to line the balsa wood (you want your rig to be all black for maximum contrast). Don’t use glossy paint! Here’s a pic  
  • Use your SiliconPutty to make legs  for the steppers’ gears                (one for each one)
    • If you are using recycled steppers as I have, you will like this:
      • Mix the two parts of the Silicon Putty                              (warning, this stuff cures fast, so have a plan)
      • Take the stepper with the gear built on and simply work the putty around the entire gear shaft as shown in this pic
    • Optional is to also make boots for the legs as I have in this pic
    • Finally use staples to fasten the legs as in this pic
  • As for the third support leg, you can use whatever you want as long as it’s supportive and static.

Here’s a pic of my finished board’s underside:

Finalize the setup:

Now that you have the rig, with steppers ready to be attached         (well screwed into the silicon putty), you can:

  • Mount the WiiRemote as to have an overhead view of the well lit rig.  This is where I just used an old work-bench light + rubber bands (see the video for a good shot).  Make sure that all the corners are see-able by the WiiRemote (I didn’t bother making a camera/perspective matrix, so you want to be as true/square as possible). Here’s a pic
  • Connect the PC power supply (or whatever you’re using) to the motor shield along with the stepper motors’ wires (I had 4-wire dual steppers).  You will have to make sure you have the relative directions correct, so the control system’s idea of front / right are correct. Pic: 
  • Upload the Sketch BallControl Arduino Code, to the UNO, and then use the processing sketch BallControl Processing GUI Code to run.

.. Have fun, I hope to see some really cool extensions to this simple idea…