From the business end

October 21, 2008

Here is a reverse angle shot showing the backglass, the scoring hoops, and the LED scoreboards (single digit, alternates with an animated arrow pointing at the hoop).  The area from a few inches in front of the flippers was all sheet cake (red/yellow/blue area).  The big yellow button was the ball launch button, and the squares on either side were speaker covers.  


POST Muckem

October 21, 2008

John here.  The push to finish the cake once I arrived in Austin was intense and involved a lot of running around for parts and not a whole lot of sleep.  My part was making the flippers work and helping out with the assembly.

Arriving in Austin, I was united with the servo gearsets and gears that I ordered from Servocity. After a combination of changing the Hitec 645 gearsets to 625s (a speed for torque trade) and an external 2:1 gearset (again, more speed)…well it was heartbreaking: the newly very fast and still strong servo + gear combo thwacked the 3/4″ delrin ball a mere 2 feet up barely-inclined melamine.   I had a 1″ delrin ball and a 13/16″ bearing, but they just made a piddly short rainbow shape. It was sad, so sad. Lesson learned: there is no substitute for solenoids.

Having learned that lesson, I went into overdrive to find some proper flipper mechanisms. There were some parts around from playfields I had bought (to make coffee tables, Shorty’s style, but it would be waaaay easier to find a complete mechanism. I called around town and (as time was running out) was helped by the awesome and friendly Brandon at Oldies But Goodies Pinball. It turns out that he is the operator behind the well-maintained machines at Creekside Lounge. Best pinball in Austin, hands down (sorry, G&S).

Back at the workspace, I ditched everything electronic and went with buttons, relays and flippers, running the 43V solenoid coils on 18V. After some cogitating about proper orientation and sleeving (basically doing a flipper rebuild) it worked like a charm, even without an end-of-stroke switch: no heating, no worries. Wham! and the ball is lost in the garage clutter. Sweet victory. The other aspects of the cake came together, and about 3am we were set to go.

How we rolled.

How we rolled.

Austin 360 has a great slideshow of the Maker Faire. Wish I’d seen more of it.


October 14, 2008

The buttonmashing end of things is going to be processed by a Basic Stamp Homework Board, talking to a Seetron SSC II.  Why the ancient, pre-2000 approach?  It is what is on hand.  Also programming the BS2 on a modern Mac is a kick after years when I had a dedicated crappy laptop running DOS to do Stamp / MELABS compiler / programmer stuff.  Also, major efforts were done in two nights, one of which was digging stuff out of bins in the basement:  Buttons, wiring, servos.

I had some fairly nice servos on hand:  HS-5645 and -645, which I was hoping would work.  While they were fine brutes for turret-nudging, they are a bit slow for the flippers.  I am off to the vendors for some faster servos.  Whatever I end up with, I am going to overvolt them (at least 7.5V) to get more speed and torque out of them.  Word on the street is that the internals are robust to around 9V, so thence I go.


We are making good progress on the cake.  Here is of in progress picture:

Pinball Cake

Pinball Cake


Pictures of past cake projects

  • Full pinball machine size L 55″x W 28″x D 5″ flat, with hard fondant frosting.  Angle of incline is traditionally about 7 degrees, but we will use whatever works for good gameplay.
  • The bottom portion of the cake will be frosting on plywood, with only upper sections as proof that it is “cake”.  Any section with electronics will be “fake cake”/iced plywood.
  • Cake will sit on plywood base with handles to help in moving (cake will likely weigh 50 pounds plus.)
  • It would be cool if we gave out cake to people who get a high score, but that necessitates plates, forks, mess.  Food vendor regulations, perhaps?
  • Outer Walls/Borders are made with compacted rice krispie treat also covered in fondant.  Integral struts and dowels connected to the plywood base for support.
  • Lower walls of playfield protected by stretches of rubber or metal if there is a lot of impact erosion in play testing.
  • Plexiglas shield covering player end avoids icing sampling, ball tampering, and air balls leaving playfield.
  • Art graphics for the plastics will be printed on icing with edible ink to add realism.
  • Obstacles on playfield will be made of rice krispie treats covered in fondant.
  • Multiple fondant-covered items for props (outside of playfield) to help explain the build process.


  • Although we could use actual flipper mechanisms, they are pretty large and power-hungry, and require two-stage coil power management.
  • Servos are cheap.  May need faster or stronger ones than the generic ones.  Early playtesting with large on-hand servo collection will clarify what we need.  Driving the servos can be done two ways:
  1. Microcontroller: PIC or Stamp reading buttons, jiggling ports to do servo timing, reading sensors.
  2. Microcontroller: PIC or Stamp reading buttons, talking to SSC servo controller board.  Better for multiple servo situation (toys, bumpers).
  • Flipper plastics:  a plastic flipper body could be glued to a servo horn with extension to lift it above frosting layer.  Most flippers have long shafts and go through a nylon bushing to prevent wobble.  This shaft could be attached to the servo.  We have a spare playfield and will try both approaches.
  • Flipper rubber:  essential for bounce and looks.  We have a few in “pencil eraser red” but might use green or purple depending on theme.


  • Standard arcade buttons installed at playfield width in a box isolated from the cake, maybe even on a stand alone table/saw horse. (a pinball machine is 300 pounds and can be nudged slightly; the cake will weigh less than 100 would be batted around if buttons were attached to cake unit).

Ball: Will be chosen based on interactions with fondant, play quality

  • Gumball – nice colors, fits with edible theme
  • Ceramic Twilight Zone “powerball” – 20% lighter than standard; lower friction
  • Smaller-than-standard pinballs (often used on smaller games)

Ball Launch:

  • Possible to kick it up a ramp or tube to the top of the playfield, let it come back down through the playfield.
  • Or:  just kick it out lightly from the between the flippers to one of the flippers.
  • Need a switch to both detect ball in drain (game over) and ball ready for launch.
  • “Launch” button or hold both buttons when ball is drained to launch.
  • Vertical upkicker (VUK): very useful assembly; can be used to detect ball (game over) and launch ball a fair distance for either launch option.

Playfield “Toys” for ball control, scoring:

  • wire ball guides, particularly lateral to flippers, will be needed
  • spinners – these are easy to mount, gratifying to hit
  • pop bumpers
  • skinny balloons and rubber rings between posts would give bounce, will be useful for playfield tuning.

Pop Bumpers:

  • Difficult to implement, but cool, giving things a traditional pinball feel.  They are iconic and allow more scoring options, lots of randomness, and visual appeal.
  • Traditionally there is a disc at top or bottom that the ball moves, which trips a microswitch and causes the cap to “fire” downward.  May need a solid base around it to prevent icing indentation, as action is intense.


  • plywood box with fluorescent illumination to back light color graphics.  This will be done with color prints mounted behind plexiglas.
  • Old school LED scoring vs. backlit LCD with “big digits” mode.  Either way, updated by microcontroller.


  • Minimally, we will have computer speakers playing a theme song.
  • Sound effects with playfield toys and other events might be added.

Stand alone display will included “making of” photos that document the process, providing edutainment around both the engineering and the cake making.