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    Mini Pinball Angles
    Mini Pinball Prototype with rendering of lower play field hardware, factoring in angles of ball deflection.


    We're working on wrapping up the Mini Pinball. Most of the hardware is figured and finished. It's time to figure out how the game will actually be built. Previously, Ben and I devised a tab and slot system that utilized laser cut wooden walls that could slot into various holes on the upper play field. We even figured out that we could add living hinges to the wood walls to add curvature.


    After a long break from the project, we put our attention back on the play field and discovered a hitch. Now that the flippers are in place and working, Ben was able to see the actual angles in which the pinball would be entering the upper play field. Our walls were previously set to 90 and 45 degree angle options. If you look at the drawing in the above image, you can see that the angles that the pinball would travel would not work well with the angles we had available. We need a new solution.


    At my previous job at the Game Crafter, we had stands that would hold cards or chipboard game pieces vertically. When we were first talking about designing barriers in the upper play field, I had thought to use pieces that would perform similarly to the game stands. However, I was worried that the pinball would hit the stand and not the wall. We came up with the tab and slot system instead.


    This week, with our minds back on the problem of being able to have sturdy walls with varying angles, I reconsidered my old idea. Looking closer at the pinball, I noticed that due to the curvature of the ball, there was much of the ball that was below the point of contact, possibly enough for a clip to hold the walls, without interfering with the ball. So I pitched the idea to Ben. The clip holding the wall could only be maybe 1/8" tall and not very thick. The walls need to be locked into the desired angle. Using just a screw does not work well as it would have to be fairly tight for the wall not to rotate in place, and given that our walls are laser cut, there isn't a good way to add a hole to the thickness of the wall. I realized that if the wall clip had a plug that was star shaped like a Torx bit, then the plug could be inserted into the board and the clip could be rotated to multiple angles, but would still lock in place.


    Wall Clip

    This gets inserted up through the play field. The thickness of the toothed bit is within the thickness of the play field so only the angled upper portion is exposed.


    After some design discussion, Ben 3D printed some prototypes. They seem to work fairly well. The ball doesn't make contact with them. The holes in the play field are now more round and could allow for insertion of other sensors and mechanisms better than the previous cross design. Ben designed the clips to be inserted from the bottom of the play field so that the wall pinches the play field, holding the clip in place from the top. The downside is that this requires removing the wall from the clip to make any changes. My original concept had the clips inserted from the top of the play field so that once the wall was inserted, it would not have to be removed for experimentation; the wall and clip could be moved as one piece with the clip removed and reinserted into holes. Once the player was happy with their design, they could use a screw and washer to secure the clip in place from underneath.

    The flaw in this design is that it requires the clip to have a slight lip that would catch on the top of the play field, otherwise it might fall straight through. The part is 3D printed from the bottom up and the lip would create a 90deg horizontal angle which doesn't work so well in 3D printing. We may still be able to play with tweaking that design by adding alight angles to the lip to get it to 3D print.


    Either way, I think we've got a solid idea and are making good progress.


    Do you have any ideas of how to make the upper play field layout customizable?

    Tell us in the comments below!