Introduction: Cardboard Pinball Machine Using a Pizza Box, Strawbees, and a Micro:bit

By https://usergeneratededucation.w

I wanted to develop a simple pinball machine that my upper elementary students and campers could make. I am fond of using cardboard, often combining it with Strawbees and physical computing that micro:bit affords. I used https://www.kookaburra.com.au/documents/2017/Strawbees%20Pinball%20Machine.pdf, created by Eric Thorstensson of Strawbees, as the foundation.

Supplies

  • 14" Pizza Box
  • Strawbees - 14 straws and a variety of connectors
  • Rubber Bands
  • micro:bit (with the cardboard cover that comes with the v2)
  • Alligator clip wires (2 to 4)
  • Dowels - 8mm for obstacles
  • Something to poke holes. e.g., screwdriver
  • Foil
  • Marble
  • Hot Glue
  • Optional: Makedo Screws

Step 1: Making the Pinball Machine Base

  • The pizza box is set up so that the bottom is formed (if using a new unfolded pizza box) or left intact. The lid is cut off the bottom, and the sides cut off the lid. The lid is decorated with the title of the pinball machine and other desired decorative adornments. The lid is glued onto the base at a right angle so that it looks like the backbox of a pinball machine. The cut off lid sides are glued into place as a bumper so that when the ball is shot, it can curve around the back part of the pinball machine,
  • The legs are made by creating pyramids out of the Strawbees - see https://www.instructables.com/Pyramid-Strawbee/. The two back legs are made using six half straws - 5", and the front legs by using six quarter straws - 2.5". The leg pyramids are attached to the pizza box base by inserted a Strawbee connector through the pizza box base and connecting that to the top of the pyramid legs.

Step 2: Adding the Plunger, Obstacles, and Flippers

  • Plungers: This is a bit difficult to describe in words so the images should help. Basically, a rubber band is wrapped around the middle of a double sided Strawbee connector. One end is put into a straw with the other end of the connector being the puller. In the left bottom corner, a hole is poked for the straw to go through, and two slits are cut for the rubber band off the connector. To create a straight shot, a trough is created. A bumper is attached near the left side of the plunger using a few Strawbee connectors glued onto a piece of cardboard and then glued into holes poked through the pizza box base. A double sided Strawbee connector is used to keep the straw straight. One end is secured in the side of the box and the other in the side of this bumper. To finish the plunger, a small cardboard square is glued onto a Strawbee connector, the connector inserted into the other end of the plunge and bent at a right angle to make a type of paddle. Example Strawbee plungers can be seen at https://youtu.be/64kujQjm7qA and https://youtu.be/LreIPzo_9Ck
  • Flippers: For the flippers, a double sided Strawbee connector is used; one side is glued onto a piece of cardboard, the other side is inserted into a straw. Two of them are made. Opposing holes are poked into the sides of the base near the bottom so that the straws can be inserted into them. (Note: I am not really happy with their functioning. Please let me know of any better ideas.)
  • Obstacles: Obstacles are made by poking holes and gluing Strawbee connectors into the holes perpendicular to the base. Makedo screws can also be used with rubber bands stretched between them.

Step 3: Adding the Micro:bit Scoreboard

  • The micro:bit is attached to the backbox by first putting it and the battery pack in the cardboard template that comes with the micro:bit v2 (or use the template found at https://microbit.org/get-started/user-guide/battery-pack-holder/), and then gluing it on using hot glue or rubber cement.
  • 8mm dowels are cut into 1.5" segments. Both the cut dowels and the marble are wrapped in aluminum foil. (FYI - aluminum foil tape can be used to increase its adhesive qualities.)
  • The scoring elements are mapped out. Side-by-side holes are poked in the base of the pizza box a little less than the diameter of the marble (this will complete the circuit which, in turn, will activate the scoreboard). The foil covered dowels are glued into place insuring that enough of the dowel is above the base to catch the marble and enough below to attach the alligator clips.
  • To complete the scoring component, alligator clips are connected from the dowels poking through the underside to the micro:bit.
  • Multiple scoring elements can be created using a piece of foil or copper to connect them (see image).
  • Example code for the micro:bit scoreboard can be found at https://makecode.microbit.org/_2oKa6K0Mrg2K