I’ve been restoring a Milton Bradley Microvision and am now happily at the point where I have a fully functional unit. Introduced in 1979, it’s known as the first portable game console with interchangeable cartridges. Anyone who has scoured eBay and yard sales for Game Boys knows that the monochrome LCDs of yore were fairly sensitive to heat and even just age. For a system ten years older than the Game Boy (and one that sold far fewer numbers), functional units are fairly hard to come by. But for a while, I’ve been invested in patching one together, and I plan to enjoy it until it, too, gives up the ghost1.
I’m not entirely sure why I’m so drawn to the Microvision, though I think a lot of it is the simplicity and purity that comes with a 1 bit 16x16 display. While this isn’t the system’s only limiting factor (the 16 bytes of RAM, 100kHz processor, and piezo buzzer are fine contributions), those 256 chunky pixels lend themselves to a very poetic design. Unfortunately, only 12 games were released (only 11 stateside), and as of yet I’ve only collected half of them, but the diversity shown proves that a lot can be done with a little. Part of the system design is that cartridges lay a mask over top of the display2 – this is an interesting way to play with the limited capabilities of the screen. Pinball adds four circular bumpers to the game screen, which the ball bounces off of; it also turns the upper corners into 45 degree angles which change the direction the ball bounces. Bowling has lines on the screen to denote ball return and gutters. Baseball’s overlay looks like a baseball diamond and shows where the fielders are3.
Internally, the unit is extremely simple. The processor is a Texas Instruments TMS110045, but it’s not a part of the console - every cartridge has its own processor. This was a cheap component at the time, and I can only imagine that the cost of the processor (with its internal ROM programmed for the game) was comparable to ROM and interface hardware. The TI chip was a commodity component, but the display driver (the only chip inside the console itself) was custom made by Hughes6 for the Microvision. The display itself was a custom component, and there wouldn’t have been an off-the-shelf solution for driving it. In light of this, it makes sense that the cost for the ‘special’ part would be placed on the unit, and an affordable chip bundled into each game (even if that did mean every cartridge having its own processor).
Externally, the system has a paddle (very 70s), and a 4x3 grid of rubbery buttons. The cartridge overlays this grid with either solid plastic (so you can’t press that spot), or a ‘button’ printed with what it does in-game (think Intellivision). These ‘buttons’ are cheap, crappy membranes on U.S. cartridges, and nice plastic buttons on European ones. The European buttons also use iconography or one-letter representations of what they do, presumably for localization purposes. It’s also worth noting that while all of the U.S. cartridges are kind of a beige-tan color, the European ones are bright, beautiful colors. They look better and the tactile buttons mean they play better, so they’re worth acquiring for the better games.
And what of the games? Well as mentioned, I only have a handful so far:
- Block Buster was the pack-in game both stateside and in Europe. It’s a basic breakout clone, with three rows of bricks. It has two speeds, which I will describe as fast and faster. The speed might not be so bad, if not for the fact that you have so little screen space to play with, and that the ball enters the screen randomly. This is the fatal flaw, in my opinion – you’re likely to miss quite a few of your balls before the first hit, simply because it’s so difficult to react to wherever the ball is randomly flying in from. Aside from speed (and how many balls you’ll be tossed), the only other option is a two- or three-pixel paddle. The two-pixel paddle is considerably more difficult than the three-pixel paddle. Humorously, the hardest cartridge to find is an upgraded version of Block Buster, released only in Europe. I do not own that one.
- Star Trek Phaser Strike is the worst of the games I own, so I’m getting it out of the way early. You have a fixed number of ships that fly by, which you must shoot at before they exit the screen. The paddle is unused, you use three of the buttons to either shoot from the lower-right toward the upper-left, from the lower-left toward the upper-right, or from the lower-center straight up. Actually trying to switch between these is probably a losing strategy, firing exclusively from the center seems like the best bet. You can set the size and speed of the ships, or you can make either or both parameters random, which makes it a bit more interesting. It was released in Europe as Shooting Star, and physical buttons might help this one, but I can’t imagine they’d help much. All in all, kind of a weak IP tie-in, something that has proven to be a reliable formula over the past four decades.
- Bowling is about as realistic as possible for 256 pixels. The ball comes down the return to the bottom of the screen and then bounces left to right; your goal is to press ‘Bowl’ when the ball is lined up where you want it. Pins have a pixel worth of whitespace around them, and placing your ball here does something resembling knocking the side of the pin. So, ideally you want to throw a pixel to the left or right of the one pin. If you hit the one pin dead on, you’ll get a seven/ten split, which you can pick up by hitting one pixel to the left of the seven pin or one pixel to the right of the ten pin. Scoring is in line with real bowling. It’s oddly fun.
- Baseball also does a good job of packing ‘realism’ into 256 pixels. Or, at least the essence of the game. You’re always the batting team, and you spin the paddle counter-clockwise in order to bat (which is really charming, to be honest). The overlay has the fielders printed on it, and if you hit it toward them you’re out. If you don’t you’ll go some number of bases. This seems to be decided by how close you are to a fielder, and not at random. How fast you flip the paddle doesn’t seem to matter. The pitch isn’t thrown until you wind your bat back into position (also very charming). The bat takes up two pixels, and the ball can go toward either of them for the strike zone, or outside, which counts as a ball. You can hit fouls, this stuff is all tracked as in actual baseball. It’s incredibly simple, of course, but it’s a really fun distillation of baseball. Unfortunately, I don’t think it was ever released in Europe, though at least the membrane ‘buttons’ on mine are in good shape. Cricket would have been a neat European release, I bet…
- Pinball sort of resembles its namesake, with a touch of breakout thrown in. Essentially, you have a breakout-esque paddle, and you’re trying to knock a ball around and hit the bumpers to get points. Eventually these light up, which I guess gives more points. My manual is in German, so I’m not 100% sure of the scoring details. Unlike Block Buster, you launch the ball, so you have control from the beginning. Lots of fun.
- Alien Raiders confused me at first because I don’t have a manual for it. A bunch of one-pixel ships are coming in from the right of the screen. Your ship is bouncing up and down on the left of the screen, and when you’re lined up with an enemy, you fire at it. What makes it interesting is that the paddle controls how far you shoot, and you have to be pretty close to hit them. There’s no on-screen display of where you’re aiming, so you kind of have to fire a lot just to gauge it. This one is a ton of fun. I’m not positive, but it looks like the European cartridge Blitz is the same game, though with lines added to the display overlay, presumably to aid in aim estimation.
Eventually I’d like to complete the collection of carts (though Vegas Slots is pretty low priority), because it’s a neat system and it does a lot to show the potential of 256 pixels. There have been some modern hacker-type projects for minimalist systems, like the Meggy Jr. RGB, which uses an 8x8 RGB LED array. I wasn’t being disingenuous when I referred to these sorts of things as poetry earlier, I think it’s entirely apt. There’s a beautiful magic about working within a tight set of constraints, and figuring out how to extract something new from them. Microvision did this wonderfully, and it’s a shame the system didn’t catch on with third-party developers.
- Apparently someone is trying to get new LCDs manufactured for these. Fingers crossed. ↩︎
- Jay Smith, the designer, went on to design the Vectrex. The Vectrex, too, had a limited display (a monochrome vector CRT), and it, too, used overlays to make more of that situation. ↩︎
- The game is unable, of course, to factor in the shift, which kind of wrecks the realism as far as 2018 baseball is concerned. ↩︎
- The TMS1100 is a 4-bit processor with 54 instructions and inbuilt RAM, ALU, and oscillator. It’s well-documented; the programming guide is available here. ↩︎
- Apparently some actually used Intel 8021 processors (and required two 9v batteries), but MB apparently ported all of the Intel games over to the TI chip and made that the canonical processor. I’m not sure how many Intel versions of the system (wired for two batteries) or cartridges are out there. ↩︎
- These have date codes on them, my unit with the functional screen seemingly was from 1980. ↩︎