Stack of Plywood¶
Design¶
I designed the board with Autodesk Fusion. The design was based on the template given in this youtube video, where the board is divided into thirds vertically. The upper third is for the bumpers and channels and everything that needs to be hit, the middle third is mostly emty space for traversal, and the bottom third is for the paddles. In the end, in order for the paddles to fit, the middle third was squished a bit (about half of it is gone now, making it one fifth the length of the board) in the final design.
The upper third was designed around channels, that could be hit. I drew 7 channels, by drawing a line from the center of the paddles to equidistanct points in the upper third line. Everything else in the surface was designed around ellipses, so that the movement of the ball would be as smooth as possible.
I added a bunch of points to the design, so that I could use them as guides for the hole tool in Fusion. Those holes were there so that all walls could be attached to the base plate with screws. The idea was to cut the base plate once, and the walls twice, so that the walls would be high enough for the ball to not fly over them. As I used 4mm plywood to cut them and a half inch ball (about 12mm), it would mean that the ball would still be higher than the wall, but the center point of the ball (at height 6mm) would lie lower than the top edge of the walls (8mm).
To get the laser cuttable files from the extruded design, I added to Offset planes to the design, one that intersected the base plate, and one that intersected the walls. The I just created sketch on each plane and used Project - Intersect to create a new sketch that had the lines for each. The I just exported the sketches as .dxf files, and cut them.
Graphic¶
I also designed a graphic for the board, even though I did not have enough time to put it in place.
Chassis¶
The surface also requires a box to hide the electronics, and which attaches the surface in the required angle. I used 5 degree angle, as it was what almost all hobbyist seemed to recommend.
I used boxes.py to create the box. I used the console box, as it had an angled surface built into it. The problem with it, is that while the angle could be specified, the size of the angled surface could not be inputted. Instead it was automatically determined by the angle, height if the box, and the height of the front plate. And to make things worse, the height also jumped a couple of millimeters every time the formula tried to divide the finger joints properly.
In the end, I ended up using these settings.
I forgot to add the holes for the buttons in the chassis, so I needed to laser cut them after I had constructed it. Thankfully, the chassis fit the laser cutter sideways, so I could cut the holes without deconstructing the whole thing.
PCB Holder¶
Even though I have never seen a pinball machine with wiring that is not a total rat’s nest, I thought I should (with “encouragement” from instructors) make the wiring appear a bit more polished.
There is not much I can do about the long distances between all the components, so the wiring must still exist. But I needed to do something about the loose PCBs amd relays inside the box. So I decided to make a simple PCB holder rack, which would hold all the bumper PCBs in place. I did not include tha main board into this rack for two reasons:
- The main board needs a USB cable to connect to outside world and my USB cables are short. Also, in my opinion, the USB port should be as close to the back wall as possble in general.
- There really was not enough room in the rack, after all the wires, PCBs and relays were placed in there.
I made the rack with boxes.py DividerTray, using the settings found behind this link. The idea was to make a slotted holder, that was just wide enough to hold the bumper PCBs and the relays, and to hide the wiring that connectects them together. The wiring from the main board to the first bumper PCB and from the bumper PCBs to the solenoids could not be hidden, as they were in a separate location.
Construction¶
This required just a lot of screws and a lot of patience.
Future Work¶
The whole thing needs to be redesigned once I get a ball detection system working. And once the lights are done. And the score board.