Our Design
For the interactive display, our team worked with the MakeLab's Technician Joel Opoku, to create the following design. This is a pinball machine. We originally created a dual pinball machine, but then modified the design to be single player as well to better accommodate the avaliable resources. Traditionally, pinball machine's are single player. This design was meant to encourage more students to interact with the space by encouraging them to use it together. This concept can be seen in the images below
Notably, this entire design was created to be laser cut with 1/8th thick plywood. The largest pieces on the outside of the design needed more support so we doubled the amount of wood for each of these components. The design is also mirrored so that each player has fair game. The peg board acts as a default obstacle in an of itself, but also allows student to design their own obstacles which use the pegs as support. All of the hexagons used on this board where cut from pencils. These pencils were a 0.25 inches in diameter. Lastly, all the components were made to fit together. This helped the board to remain symmetrical and ensure a greater level of precision in the construction process. For a more in depth look at this design, click on the SolidWorks file below!
SinglePlayerPinballCAD.zipDualPinballMachineCAD.zipDesign Features
Frame & Obstacle Board
This design was created to be 21 inches by 48 inches by 7 inches. It was initially designed to be a table top display. The frame consists of 5 walls. There are 2 identical long walls that span the lengths of the display and two identical short walls that span the width of the display. All of these are connected at the bottom by the base of the frame. This piece helps to provide structural support and provides a location for the electronics to be held.
The frame is responsible for holding the obstacle board at the correct position and angle. The obstacle board is the angled board with holds all of the smaller components that make the display work. This board as a 6.5 degree angle. From research online, we found this is the most optimal angle for pinball machines. The obstacle board also had to be at a height withint the size constraints, but that also provided plenty of room to install the electronics where students could see them through the access port.
Connecting Components
All of the components were built to fit together. Each of the pieces of the frame slide into one another. This ensured that components would be aligned at the correct position and would provide additional structural support. Each of the smaller components on the frame fit onto the obstacle board. This also ensured that they were in the correct locations. In CAD an offset of 0.5 to 1mm was used on the hole for each of these joints to ensure the wood would fit together without too much pressure. Additionally wood glue should be used to reinforce these joints.
Launcher
The launcher mechanism is designed to push the ball to the top of the obstacle board. It is located to the far right side of the board. Directly following the launch mechanism, is the launch path. This is about a 1.5 inch wide space between the frame and a supporting wall that allows the ball to reach the top of the obstacle board without its path being impeded by obstacles.
In this design, a rubber band is used to power the launch mechanism. The rubber band is looped around 2 hooks and the launcher slider. The two hooks are directly aligned with one another. One is cut out from the frame and the other is on a supporting wall. The hooks are placed above the height of the 1-inch ball so that they do not interfere with its motion. The launcher slider is a pencil with a circular handle on one side and a face on the other which has indents for the rubber band. The side with the circular handle is placed outside the frame and the face of the slider is within the frame.
Students pull back on the circular handle while the face of the slider is connected to the rubber band. This stretches the rubber band creating tension. The ball is located directly in front of the face of the slider. When the student releases the handle, the release in tension of the rubber band propels the ball through the launch path up the angled obstacle board. Then the ball goes through the obstacles, through the flippers, down the drain wall and eventually back to the launch mechanism.
The launch slider is designed so that the face of the slider is never higher than the drain wall. This ensures that each time the ball returns it is always left right at the position it needs to be at to be launched. We ensured that the slider is not pulled past this point by adjusting the length of the pencil dowel, so the the handle phyiscally prevents the rubber band from pulling the slider any further forward.
At rest, there is 2 inches of space between the hooks and the face of the slider. This holds the rubber band in place with minimal amounts of tension. This design allows the rubber band to be extended up to 3.5 additional inches. For more force from this mechanism, more rubber bands can be added or the rubber band can be hooked in different formations to create more tension.
The last component of the launcher is the dowel stabilizer. This small structure ensures that as the slider moves it remains in the launch path. There is also a hole in the short wall that allows the slider to be partially inside the frame and partially outside of the frame.
Peg Board
The peg board was designed as a default set of obstacles. Additionally more obstacles can be added on top or around these pegs to create more interesting paths for the ball. Click on the Make an Obstacle! page for more information on this process.
Each of these pegs is cut from a pencil. They are each about an inch long. The bottom 8mm of each peg is in the obstacle board leaving about 0.75 inches of a peg for the ball to hit. Each are glued into their respective locations on the board.
The pencils can also be substituted for dowels or other items located in your space.
Each of the pegs from 4 inches to 4.5 inches away from the surrounding pegs. This allows plenty of room for the ball to travel between pegs and plenty of room for additional obstacles to be added.
Flippers
The flippers allow the player to keep the ball in the obstacles after it was launched. In many versions of this game, players can earn points in this region. The flippers are used by the player to move the ball to score points.
There are two flippers at the base of the board. They are centered in the area where the obstacles are. They are each about 6 inches long and 2 inches in width at the widest point. There is about 2 inches of room between the tips of each flipper that allow the ball to roll past them to increase the difficulty of the game. This is a typical design in most pinball machines. These flippers could be 3D printed. However, in this case we laser cut the shape 3 times for each flipper and glued the layers together.
The flippers are each powered by a servo motor. Each motor reacts to a button pressed on their respective sides of the board. When the button is pressed the flipper moves from a 0 degree angle to an 80 degree angle with respect to the short wall of the pinball machine and the bottom side of each flipper. in about 1 second. This system is controlled by an Arduino Nano.
Drain Walls
There are 3 drain walls in this design.
The longest is the one which is located behind the flippers. This drain wall is angled such that if the ball passes the flippers, it automatically rolls to the perfect position for the launcher. This drain wall is at a 6.5 degree angle with respect to the shortest side of the obstacle board. The steeper the angle the more confident we could be that the ball would roll toward the launcher. However, if the angle is very steep this drain wall would take a lot of vertical space on the obstacle course which would leave less room for obstacles. This angle ensures the ball will roll to the launcher, but not take up a great deal of vertical space.
The other two drain walls funnel the ball toward the flippers. The flippers do not span the entire length of the obstacle region. This means that there is space behind each of them that the ball could go to without interference of the flippers. To fix this issue, two drain walls were installed to roll the ball toward the flippers instead of going behind them. This is a common design in pinball machines.
Curved Wall
At the top of the launch path there is a wall which is curved. This wall changes the trajectory of the ball such that it moves toward the obstacles on the board.
For this design we used a live hinge to curve the wall and sanded down one corner so it would naturally push the ball in the right direction.
Access ports
There are several locations in the design of the frame where there are large cut outs. These are meant to act as access points to see and adjust the electronic components which are located inside of the display. There is a large on in the base of the frame. There is a smaller one behind the drain wall, which doubles as a visible way for students to see the electronic components. We chose for the viewing port to be there because it was a large area that did not serve any other purpose and would be easily visible to students playing the game. Lastly, there is on the long wall on the left, which also provides a way to move the LEDs and microphone on the outside of the display.
QR Code
Lastly, there is also a QR code which brings students to this site! This QR code can be place over the visible access to the electronics or at the other end of the board where the bread board is not stored.
Electrical Compontents
Motor & Mount
This design contains two servo motors on each side. The obstacle board has a hole for each motor that allow it to be screwed in from the below the obstacle board. Each hole also has room for the wires to move in case the servo needs to be installed on top of the board.
Button & Mount
To activate each motor, a button is placed on each side of the of the frame. Each button is 0.5 inches in diameter. In this design we have cut 0.5 inch holes on either side of the board where the buttons will be held.
Electrical Board
The electronics consist of a breadboard, Arduino Nano, servo motors, and buttons. The bread board is place within the frame close to the short wall, so that it can be easily viewable to students playing this game. In this area there is about 3 inches between the base of the frame and the angled board to provide space for the components and for people to move their hands within to set it up. Click on the Electronics & Programming page to learn more about this process.