Learn to design a skeeball game using paper pressure sensors and Scratch.

Supplies

Makey Makey Classic, Cardboard, Extra Alligator Clips, Paper Towel rolls, Tin Foil, Painter's Tape, Klever Kutter, Xacto Knife, Roto-zip (optional), Glue gun, ruler, decorative objects, paint

Step 1: Designing the Board.

Whether you're creating a minature version or a full size version, the instructions will be the same. Only the size of the materials and how you attach them will need adjusting. (I'll be writing instructinos for a minature version)

Choose a rectangluar box and choose your style of skeeball track. The traditional skee ball has holes of various sizes depending that how you want to keep score. This skee ball track will have the same size holes, but different scores for distance.
Trace the circles onto your cardboard box. Make sure they are larger than the size of your ball so it can fall through. I'm using paper towel roles and a large marble. If you are making a full size version, you can use Solo cups, coffee tins or a compass.
Once the holes are on the box, don't cut around the hole completely! To help strengthen your "holes/cups", cut small triangles from out of the hole. This helps create flaps that you can glue/tape to the rolls (see attached pictures).
side note: if you are going full scale, and using cardboard for your cups/holes, you should still do this method, or create a double flanges. Remember that the stronger it is, the better.

Step 2: Inside the Box!

Now it's time to think inside the box!

For each hole, we need to mark where the ball is going to fall down and strike the bottom of the box (where our sensor will be).
Rather than eyeballing it, grab a spare paper towel roll and push it through a hole. Open the box and use a paintbrush to apply a decent amount of paint to the bottom of the paper towel tube that is facing the inside.
Close the box then push the tube down until it makes contact with the bottom of the box. This will leave a circle mark of exactly where the ball should land. Do this for all the holes.

Step 3: Creating the Switches!

To create the pressure sensors to activate the Makey Makey with the ball drops, we'll be using Colleen and Aaron Grave's Pressure sensors (Forr explicit directions, you can find them in the Big Book of Makerspace, pg. 173) using paper, tinfoil and tape.

To design a sensor, take two pieces of paper and wrap/glue/tape tinfoil in the centre. When you have two peices of paper with tinfoil on them, they will conduct electricity, when they are touched together (see video).
On the botom piece of paper, I ran one strip of tin foil all the way across while the top paper ran a strip of tinfoil perpendicular to the bottom.
Tape/glue the bottom piece directly over the one of the painted holes inside the box. I usually attach the ground wires to these.
With the second piece of paper, create a bend/arc in the paper so the two pieces are not touching and tape it down. You will be attaching the alligator clips that lead to the button pushes on the Makey Makey on the top. For Skee Ball specifically, make your paper arc large enough that the ball can pass under it (this will allow the ball to fall to the botton of the box and exit).

Makey Makey Skee Ball Game - Step #3
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Step 4: Hooking Up the Makey Makey

There's a reason why we don't see what's inside an old aracde machine. It may look messy and there are lots of wires, but with a little color coding and tape, it will be super easy to hook up your Skee ball!

To easily identify your alligator clips, I try to keep all my ground wires the same color (see picture using green wires). Attach the ground wires to the bottom paper on the section of tinfoil. I recommend taping them to the side of the box to keep them out of the way. Next, attach each clip to the ground pins on the makey makey.
Begin attaching the colored alligator clips to the top pieces of your sensor to the foil, tape them to the opposite side of the box and attach them to the the arrow and space inputs of your Makey Makey.
On two top scoring cups of the Skee Ball game, both of them are the same number so you can simply attach two clips to each other and run another one to a single pin in the Makey Makey
Plug in your Makey Makey and your ready to code in Scratch.

Step 5: Coding Your Game in Scratch

When coding your Skee ball game, there are plenty of options to get more advanced with sounds, pop-ups and animations. These steps will cover the basics.

The great thing about coding a game in Scratch is that you can add as little or as much as you want. I found a picture of a Skee ball game, made a ball (sprite) using the costume editor, added sound and kept score.
First, if you're keeping score, you want to make a variable called score, which will change depending on which hole it drops into. Set it to zero when clicking the green flag to start your game.
Next, we program each hole/pressure sensor that is attached to the Makey Makey. When each key is activated, you want to change the score by whatever amount you assign. Make sure you have the correct key activated in Scratch to correct sensor in the box so your scores match.

Those are the basics of programming for Skee ball, but here are suggestions to add to your game.