A short time ago I built a miniature version of the 1981 electronic board game Dark Tower as a gift. This project combined 3D printing with some electronics and game programming. It was a ton of fun to design and build.
I decided to record the process and put it up on YouTube. This was a promise I made myself for 2022 to get more active in the Maker community. This is one of the first projects I recorded. As you might expect, most of that recording was garbage. Just me rambling while working on the project with a camera in one hand. Thankfully, through the wonders of editing, I was able to distill it down into (I think) a couple fun videos. Check them out over on my YouTube channel.
I’ll take a moment here to beg for a click on those Like and Subscribe buttons. Seriously. It means a lot to have these efforts validated with a thumbs-up. Costs you nothing and lets me know folks are out there. Constructive feedback is also appreciated so can improve the quality of the next video project. Want to see more details on coding? The 3D design process? Assembly? Help guide the next video project by letting me know what aspects you want to see more of.
Wanna build one? Links to the source code, 3D models and parts list can be found in the second video description.
Part 1: Intro to the game and the plan to rebuild it.
Part 2: Doing the thing I said I’d do in Part 1. 🙂
I have a few video projects coming up in the new year. We’re getting an old C64 back up and running, remaking a classic 1980’s electronic board game with Arduino, 3D printing some robot gears and trying our hand at crafting a mini pinball table. It’s gonna be a full 2022!
To kick things off a little early, I’m launching the first series before 2021 ends. This is about finding my own 1984 computer in my parent’s attic and the process of getting it running again. Check it out over on YouTube, and do the “like“, “subscribe“, “comment” thing while you are at it. 🙂
UPDATE: Parts 2, 3 and 4 of this epic struggle have also been published. Check out the whole series. We cover video issues, broken audio. discolored plastic and busted keys. There was no part of this C64 that wasn’t broken. *sigh*
Miniature arcade machines were all the rage this year. A couple manufacturers offer different sizes, from 4″ tall, to 6″ and 10″ toys. I was given the ‘My Arcade’ Pac-Man 6″ cabinet for Xmas, and I deserve credit for waiting a whole three days before breaking it open to look inside. 🙂
Regardless of whether you pick up the 4″ Tiny Arcade or the 6″ My Arcade version of your favorite game, chances are there are more games locked inside. To reduce manufacturing costs, groups of these games share a common circuit board and chip that contains 4-6 games, with only one of the games ‘unlocked’ for a particular toy. With a bit of modification, you can unlock the other games.
For example, the My Arcade 6″ Pac-Man I was given contained a total of 6 games:
Pac-Man
Galaga
Mappy
Galaxian
Dig-Dug
Rolling Thunder
As far as I can tell, Rolling Thunder isn’t even released as it’s own cabinet yet. The others can be found for $20-$30 at different stores. So, by unlocking them in my Pac-Man cabinet, I saved $125. I probably spent more than that in terms of time devoted to the mod, but that’s largely my own fault. More on that later.
Choose Wisely!
The Pac-Man I modded was a gift, but had I picked a cabinet to modify it would have been a different model. The 6″ Pac-Man from My Arcade contains no buttons, since Pac-Man does not require anything other than the directional controls. In order to make use of the unlocked games, which all require some kind of jump or fire input, buttons will be need to be added to the cabinet. If you are looking to mod one of these toys, save yourself the trouble and pick one that already has buttons.
Stickers Can’t Stop us!
The first step is opening the cabinet is to remove some of the artwork stickers from the outside. Screws are hidden under the side artwork, and the top sticker crosses a seam that will need to be separated. Using a heat gun or hair dryer. Soften the glue and peel back these stickers. They are fairly thick and easy to remove once you get a corner up. Keep them somewhere safe for reassembly.
*2019 UPDATE* When I posted this article on the ‘My Arcade/Dream Gear Minis Fan Club‘ page on Facebook, someone replied that they were able to open their cabinet without removing the side art. On mine, the side panels had little wood screws under the stickers, and one poked through far enough to hold the back of the cabinet in place even after the 4 back screws were removed. Maybe I was just unlucky. Check yours first by removing the screws on the back of the cabinet before removing the side art. You might be able to skip this step.
With the side and top stickers removed, the screws can now be removed and the cabinet opened.
For cabinets with buttons already installed, these are all the stickers you’ll need to remove. If you are adding buttons to the front panel, you’ll also need to remove the front screen bezel sticker and plastic guard in order to remove the screen frame and slide out the control board.
Three bits, but only six games
Remove the main circuit board from the front of the cabinet and have a look. Under the padding, you’ll find three pairs of jumpers labeled IOB1, IOB2 and IOB3. These jumpers determine which game is unlocked in a particular cabinet. In this case, IOB1 is connected to enable Pac-Man. Through experimentation, I found that IOB3 unlocks Galaga and IOB2 unlocks Mappy and no connections unlock Rolling Thunder. But that’s not all. Some combinations also unlock games. IOB1 + IOB3 is Galaxian and IOB1 + IOB2 is Dig Dug. Sadly, although there are eight possible combinations, I was only able to find six that resulted in unlocking a game. All other combinations just launch Rolling Thunder, which must be the default game on the chip.
Since we need to independently set all three jumpers, I chose to remove the existing IOB1 solder joint and wire each pair of jumper pads to a switch. By setting the appropriate switches, I can then control which game boots when the power switch is turned on. Note that all three left pads are on a common trace. You only need to solder one wire to these pads and chain it to all three switches.
Here’s a drawing to help clarify. A switch is added across each jumper pad pair so they can be toggled by the user to pick the game before turning the system on.
If no switches are closed, the system boots to Rolling Thunder If only SW1 is closed, it boots to Pac-Man. If only SW2 is closed, it boots to Mappy. If only SW3 is closed, it boots to Galaga. If only SW1 and SW2 are closed, it boots to Dig Dug. If only SW1 and SW3 are closed, it boots to Galaxian.
All I had available were some old Radio Shack push buttons, so I drilled three holes through the back of the cabinet and wired each to one of the jumper pads. By holding the proper combination of buttons when powering the unit on, I can now select one of the six games to play.
Use Caution! (and glue)
These circuit boards contain very thin traces. Try not to repeat the mistakes I made. If you solder a wire to one of the IOB pads, any slight tug on that wire will pull the pad and most of the trace it’s connected to right off the board. I did this more than once, and repairing circuit board traces can be a nightmare. In the microscope image below, you can see how the lower-right pad has been removed and also pulled a good chunk of copper trace with it. After taking this image, I did this two more times. *sigh*
In the end, I spent an entire afternoon repairing the board of a $25 toy. My advice is to make sure you hot-glue or tape your wires down as soon as possible to avoid pulling them off the board, and practice your soldering skills to make sure you can connect items quickly without burning a trace. You’ll also need a sharp soldering iron point to work on these small areas.
Control Issues
Since the source for this mod was a Pac-Man cabinet with no game buttons, some will need to be added. Otherwise, we can’t play any of the unlocked games. All the unlocked games require one button except Rolling Thunder which needs two. Luckily, the control board is also shared between all the cabinets. The button pads are present, but simply unpopulated on the Pac-Man machine.
For my mod, I chose to just wire two more small buttons to the A and B pads, connecting each to GND when pressed. The switches are small, since I wanted to minimize the size of the holes I need to make in the control board to preserve the artwork. I also shifted them up so they’d work well with the Pac-Man art. Small felt bumpers were hot glued under each switch to raise them up to the height needed.
The end result works, and the small black buttons are somewhat camouflaged by the dark background of the Pac-Man art.
Conclusion
With a bit of effort, and a source cabinet with existing gameplay buttons, this mod can be done in an evening. With my poor luck damaging the board and needing to add additional gameplay controls, the mod took two days. Still, it’s a fun modification that results in 5 more games to play. Highly recommended.
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