See inside a cereal surprise: Dissecting the Xbox Mini electronic games
Freebie handheld electronic games—included in cereal boxes—pack in a lot of engineering ingenuity.
By Brian Dipert, Senior Technical Editor -- EDN, February 15, 2007
Image Gallery
Click on any image for an extreme closeup. Links to the full-size images also appear within the text.
Mystic Castle
Disco Mania
Motorcycle Madness
Spaceship Blaster
Microsoft continues to deny rumors of a handheld Xbox game console (other than the UMPC or Pocket PC, that is), and the company isn't promising gaming on Zune until mid-2008. You can imagine my surprise, then, to recently open up a box of Frosted Flakes and find a inside! In all seriousness, the Xbox-branded toys that Kellogg's gave away inside boxes of breakfast cereal are one example of a multiphase promotion partnership between the company and Microsoft.
The Xbox Mini Games won't run Gears of War; for that matter, Geometry Wars: Retro Evolved is even beyond their reach. But I thought they'd still make a fun Prying Eyes project. To wit, how do you make an electronic toy inexpensive enough that it can be given away within a box of Froot Loops while still retaining enough compelling features to motivate a cereal purchase?
The first game I obtained, and therefore the first one I dissected, was MysticCastle courtesy of the above-mentioned Frosted Flakes purchase. A fiscally friendly Ebay acquisition (is there anything you can't buy on Ebay?) also routed Disco Mania, Motorcycle Madness, and Spaceship Blaster to my door. Alas, I wasn't able to come up with a Robo Blast unit, but if any of you have one, I'd love to take a peek at it! I can't absolutely promise that it'll still be functional when I'm done, but so far I'm four-for-four, as the active displays on these post-reassembly pictures, complete with instruction sheets, prove: , , , .
Step 1 was figuring out how to get inside the case, a challenge I've also needed to surmount with past Prying Eyes adventures. As you , Mystic Castle (along with, for that matter, its siblings) is held together by screws containing uncommon Triangle Recess (TP3) heads. A few minutes' worth of Googling led to a helpful discussion thread, which directed me to the McMaster-Carr website (search on "Triangle Screwdriver Bits"). A few mouse clicks, a few bucks, and a few days later, I was all set.
Remove four screws, separate the halves, and you end up peering at the inside of and portions. The "Made in China" label on the back of each game, along with the games' low-tech layout, suggests to me that they're likely hand-assembled. Note the little touches that assist in maximizing manufacturing yield, such as the plastic pins that hold the wires connecting the single-layer PCB and speaker in place so that they don't get pinched by the outer case. Note, too, the test points on the PCB, which may also find use in programming game code to the unit...that is, if the controller isn't a dedicated logic state machine, which may very well be the case given the unit's elementary function.
You can also see the five membrane switches that partner with plastic buttons on the game's top side. The PCB and its companion display mate together via five tiny Phillips-head and connect to the back panel through two press-to-mate plastic pins in conjunction with two other alignment pins. Note the crude-but-effective plastic power switch, which mates with a thin metal lever whose function will be clearer in a bit.
Remove the display and you get a clearer . If you toggle back and forth between this image and the earlier , you'll eventually figure out how the PCB gets powered: one battery connection presses up against a circular contact on the PCB, while the power lever mates with an oval contact. When the thin metal lever, shifted from its default position by the power switch, makes contact with the side of the battery, it . Mystic Castle is intended for discard once the battery is depleted, but the power source is replaceable if you can get past the nonstandard screws that hold the case together.
The PCB is bare of components, save the mystery game-controller IC buried under an epoxy encapsulation cap. To the right and left of that, you'll see the two vertical contact rows, containing eight contacts each, that drive the LCD. How do signals get from the PCB to the LCD? Note the two flexible pink pieces, with embedded black sections, on either side of the plastic frame. Removing the frame gives a of them. According to EDN analog technical editor Paul Rako, they're "zebra strips," elastomers containing alternating bands of conducting and insulating material. Note, too, the hand-drawn alignment mark on the back of the LCD's backing cover. The cube-shaped spacer sits between the backing cover and plastic frame.
Did any of you play with or, depending on your age, have kids that played with the Magnavox Odyssey video game in the early-to-mid 1970s? This pioneering console, which predated Atari's Pong by approximately 3.5 years, only had enough graphics muscleto render a single light blipon the screen. In order to customize the TV display for each game, you needed to apply a see-through plastic overlay sheet to the front of the CRT. I got a strong feeling of déjà vu when I peered at the Mystic Castle LCD reflective , because it incorporates a similar game-specific overlay (or, in this case, I guess I should say underlay) graphics image. You can also see the contacts embedded within the backside of the LCD, which mate up with their counterparts on the PCB courtesy of the zebra strips.
Next, let's look at Disco Mania, beginning with its - and exterior. In this and the following two product writeups, I'm not going to reiterate already-made points but will instead focus on aspects that are new or different compared to the games I've already discussed. 's what the device looks like when you remove its two retaining screws. This time, the four membrane switches reside on a separate PCB, connected to the main PCB via soldered wires. The power switch and its accompanying battery lever are, as will be the case with the next two games, identical to the Mystic Castle, design albeit dimensionally altered to fit the specific device requirements.
Note that in (and, for that matter, the subsequent two cases) the PCB-to-speaker interconnect is not made via two wires. as was the case with Mystic Castle. Instead, two small spring-loaded contacts protrude from the back of the PCB and make physical contact with distinct areas of the speaker. And this time, several small passive components on the PCB, in addition to the encapsulated controller. There's only one row of display contacts, and therefore one zebra strip, , and the LCD's reflective backing cover is absent any game-specific image. We won't see one on the other two games, either.
Next up is Motorcycle Madness, beginning with and views. Remove the two screws, wriggle some retaining clips free and break through a bit of adhesive, and you can see inside the and . The two membrane switches on the left "handle" appear to share a common ground connection, judging from the three wires that run between that particular PCB and the main board. , the spring-loaded proximity connections between the main PCB and speaker . Like Disco Mania, Motorcycle Mania requires only a single row of and therefore a , and its PCB supplements the controller with a few small discrete passive components.
Finally, let's look at . This game is unique among those I disassembled in that it contains both a front-side knob, twisted by the player to orient the "cannon," and a . The trigger proximity-mates with a , which electrically connects to the main PCB via a two-wire harness. But how are the user's 45-degree twists of the front panel knob communicated to the game controller?
and you'll have your answer. A clockwise or counter-clockwise twist shorts together one of the two sets of dual contacts on either side of the control knob. Follow the contacts up toward the display and you'll see that like the power lever, they press-connect to the PCB. This isn't an approach that's conducive to long-term reliability but, then again, the game wasn't designed for long-term use. A tension wire auto-returns the knob to its neutral position after release.
As was the case with Disco Mania (12 contacts) and Motorcycle Madness (16 contacts), Spaceship Blaster employs a single-row connection to the LCD, comprised of 16 contacts, versus MysticCastle's 8-contact dual-row approach. Also like its two predecessors, and unlike Mystic Castle, Spaceship Blaster's PCB includes both the controller IC and several passives.
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