Thursday, May 11, 2017

Journey to a Fully Custom Pinball Machine - Part 1

The"maker bone" has bit me pretty hard since 2011 when I began working on LEDgoes/BriteBlox and won 3rd place the Apps for Metro Chicago hackathon with Owtsee/headonout.  And while I've worked on a mixture of side projects for profit and fun since, I can't help but note the urge to do more ridiculous things for myself just to say I did them -- not necessarily to make any sort of profit (in fact, most of my projects sink an enormous amount of time spent over several years before true completion), but for the notoriety.

The Actual Beginning Of This Post

There... Now that the part Google Plus will post as the headline is out of the way, it seems to me that my coworkers generally love me, and I love them too.  I am seen as quite the maker type inside my area, and have been invited to participate in events even in various groups I don't necessarily belong to because they like to "claim" me.  Often, these are external recruiting events, and I love exuding the ideals of our culture while getting a bit of exposure for my stuff, and it's even more fun to see the people I meet at these events working inside my office within the ensuing weeks or months.

It should be noted that the ROM hack of Tapper was done for the first such event.  I gave them a choice between me coming up with a clone of Microsoft's "Rodent's Revenge" (rethemed with elements from our business) or retheming the Tapper arcade game to show the logo of where we were rather than the Budweiser logo.  They picked the latter, thus that was born.  It even turned into a class I give periodically.

For the next event a bit over four months later, I sent along several ideas for things I could show.  They picked BriteBlox, despite that I pretty much showed that already along with Tapper.  I was a little less enthusiastic to simply show another LED light show, so I brainstormed about what else I could build around an LED light show.


I was inspired, with only about a month to prepare, to combine this endeavor with something else on my agenda: making a custom pinball machine.  I'd already had in mind several things I wanted to experiment with on my very own game, and with not a lot of time left (read: time to write tons of game logic for different modes, not to mention wiring in all kinds of switches, drop targets, and toys), I actually opted to neglect the Bally Ms. Pac-Man cabinet I bought solely for the purpose of making my own full custom game (I even sanded all the paint off it a while back already) and go with a custom cabinet design that's only about 60% the size of a full commercial game.  This way, it wouldn't look so empty when I don't bother to populate the playfield with a whole lot of game elements, and it's also "easily" portable (you can pick it up by yourself without needing to tie it up, strap it to a dolly, take legs off, etc).

T minus One Month

After talking to someone particularly enthusiastic about my project, I knew I had to act fast.  I dabbled around with a Windows program called Visual Pinball to build and test my layout on the computer.  Version 10 has a fair number of idiosyncrasies, and although it's an open-source project, it requires a fancy version of Visual Studio that has some development libraries the free version doesn't come with.  So much for trying to make it the way I like it... Nevertheless, with enough perseverance, I managed to build myself a nice layout that seemed to play well, especially when I learned how to play "two-dimensional piano" in order to nudge the game (in the simulator) every which way to make the ball really go where I wanted it to.  (Is it wrong that I designed a game that requires nudging in order to be fun?  I feel like it adds to the skill of a well-rounded pinball player...)

Of course, any time I'm dealing with CAD software (even if it's a pinball simulator), I spend a whole lot of time with geometry.  Most of this was fairly simple measuring, but still tedious as I often liked to write down all the measurements to the ten-thousandth of an inch.  This is far more precision than I really needed for the CNC router, but I wanted to make every effort to ensure it would play in real life just like it did in the simulator.  This meant collecting precise alignments of the lanes, the round area in the back where the ball curves over onto the playfield after the initial shot, the pop bumper, the slingshot holes, rollover targets, general illumination... you get the idea.  Once it was all measured, I duplicated everything into VCarve (our program of choice for the CNC router), which took yet more time just from the sheer number of elements required for even a fairly simple playfield.  And this didn't even account for any "stencils" as to where mounting hardware for all the playfield accessories would go; I ended up attaching them by eye, hand, and feel later on.

What's new with this machine?

To summarize some of the enhancements I presented to the crowd at this recruiting event, and at the Texas Pinball Festival a couple weeks later:

  • High-end servo motor instead of complicated traditional flipper mechanisms
  • 3D-printed brackets as mounting hardware for many rollover switches & general illumination
  • Rollover targets consisting of inexpensive yet highly durable computer keyboard key switches rather than expensive specialty pinball switches that require constant cleaning and/or calibration
  • A DMD display consisting of a 24-panel BriteBlox LED matrix
As development went on, I also eliminated the need for a switch matrix by using an I2C port expander chip; more on that later.

Also, to increase our Intel street cred, I used the Intel Edison development board with the Arduino Breakout Kit, and fabricated my own driver board consisting of MOSFETs to drive the solenoids and pull-up resistors for every single switch.  No expensive P-ROC boards for me!  I'm doing this fully my way.  I know enough about single-board computers, development kits such as the Edison, and embedded C/C++ programming to just go about this myself... right?!

Stay tuned...

Usually I detail a project in a single blog post, thus many of my posts are really long.  Instead (because I'm crunched for time tonight anyway, and because this can easily be talked about in stages), I am going to write several posts on this project over the next few weeks, detailing the ins and outs of my journey.  And honestly, it has only been about three months since I started, thus the requisite number of years before I'm truly finished with something have nowhere near elapsed yet.  As such, there are still quite a few quirks with it (especially electrical gremlins) that I need to fix, and all that will be detailed here too.

I especially want to talk about my fights with MRAA and the Arduino Breakout Kit, and some of the "fun" involved with sensing multiple switches rapidly, from a technical standpoint anyway, and then of course get into softer things such as artwork and the game's logic and theme, and possibly a bit on fabricating the cabinet (which seemed to take a great deal of time).  Be sure to check in on Thursdays around this same time for future posts!

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