What makes Blip tick?

After our Tabletop Pong project, someone suggested that we should check out the Tomy Blip, a handheld game dating to 1977.

And so we did. We snagged one on eBay, and here it is: "Blip, the digital game."

Blip is unlike any other handheld that I've played, and (as you'll see) it's quite a piece of engineering. In what follows, we give it a test drive, and then take it apart and see what makes it tick.

The best introduction to Blip that we've come across is the original television commercial. We're embedding it here, but you can also view it at YouTube.

Blip was advertised as a portable digital electronic game; a go-anywhere version of Pong. The box bears this out as well:

"NO TV set is needed."

And here's what it looks like in real life. It looks sharp. There are one-player ("Player against machine") and two player modes-- it sounds pretty advanced.

It turns out to be actually electronic, but only barely. Two AA cells are needed, and they have only a single purpose: to light the LED. The game itself is fully mechanical, and is (except for the LED) actually powered by turning the "timer" knob to wind up the main spring that runs the game. If you've ever played the game Perfection or used kitchen timers of similar vintage you'll be intimately familiar with the noise that the mainspring-driven motor makes as it unwinds. It sounds distinctly non-electronic.

The only part of the game that's remotely digital is the scoring, which is indeed digital: the score is recorded as a number. Of course, that means that it's exactly as digital as foosball, or perhaps even golf or (genuine) tennis. The score is displayed on a pair of ratcheted wheels. Your score advances when the opposing player missed the "ball" and has to serve the ball back to you, and it is the action of them pressing the "serve" lever that causes your score to advance. We'll come back to this later.

Playing the game is hard; We have a video a bit further down that will show you just how hard.

The ball wanders back and forth in an apparently random fashion, seemingly never in a straight line. As a player, you wait for the ball to be headed in your direction and then try to guess ("Anticipate" in the words of the instructions) where it will end up. Your only controls are the buttons labeled 1, 2, and 3. If you press the wrong one, the ball stops, and you need to serve the ball back to your opponent (giving them a point) by pressing the red "Serve" lever on your side. That's it. No choice about where to send the ball to the other player, and it feels like more of a game of chance than of skill.

Of course, we'll have more fun taking it apart.

And then you look at the other side and... well... holy crap! (Click here to see that larger.)

Again, this game is almost entirely mechanical. The buttons on the left and right are not electronic buttons, but levers that mechanically stop the "ball" from traveling all the way to one side or the other. The ball is not the lit portion of a of a larger LED display, but is an individual LED on a moving arm that goes back and forth. The only electronic circuit consists of the two AA cells, one resistor, and that LED.

The mechanism that moves the LED back and forth is hard to see here, but it is described in detail in this patent which has drawings of the inner gears that you can't see well in our photos.

Here, you can see the levers beneath the right-hand side buttons. Normally the front face of the Blip pushes these down somewhat, so that they block the path of the "ball." If you press one of the buttons, that causes the "ball" to miss the lever, and then go back to the other side. The red bracket over the top is the "serve" lever. It serves to dislodge the ball if it gets stuck, by moving all of the levers out of the way of the ball. If you hold this lever down continuously, you will never miss the ball. (That technique is demonstrated in this video.)

You can also see that the serve lever hooks into a grey lever down below. When you pull the serve lever down, this grey lever ratchets the opponents score up by one.

On the left-hand side of the game is a black lever that switches between one-person and two-person play. If you look closely, you'll see that it works by effectively holding down the serve lever for the left-hand player. (Human plays on the right side.) This means that it uses the same "cheat" that we just mentioned-- and also that the computer never loses. Ouch.

With the 1, 2, and 3 buttons and the serve levers removed, you can see the two levers (black and gray) that are used for the automatic digital scoring.

The little sliding bracket on the upper left sits beneath the buttons, and provides sequencing. If you press any of the three buttons, this bracket prevents you from fully depressing either of the other two. It's spring-loaded to return to the center position, and the spring mechanism too is clever-- just an extended arm of this bracket flexes to hold it in place by spring action, as visible in the previous photo.

The electrical feedthrough to the moving LED is a simple pair of flexible wire leads. These are thin and could be genuine wire-wrap wire. They're held down by a couple of strategically placed blobs of plastic.

The mechanism and style of motion-- a bit like planetary orbits --are a little hard to understand from the still photos. The purpose is to create a sort of mechanical pseudorandom motion generator, and it succeeds somewhat, in so far as the game is difficult to play or guess where the ball is headed.

To help out with that visualization, we've put together a little video that shows off the gameplay (such as it is) and then, after taking the cover off, shows the magical workings of this nifty little mechanism. The video is embedded below, or you can click here to see it at YouTube.