Opentilt: Tag, You’re Out!


Have you ever heard of the game Johann Sebastian Joust? We haven’t either, but [Juerd] has come up with an open source version of it called Opentilt, and we have to admit — it looks like a lot of fun!

Johann Sebastian Joust uses motion controllers for a game that can be played indoors or out, without a screen. Everyone gets a motion controller, and the object of the game is to make everyone else move their controller too fast. It even has a music mode that lets you move your controller relative to the speed of the music! Anyway, it had an extremely successful kickstarter, and it has been debuted at many events around the world — but it’s simply not available to the general public just yet. [Juerd] couldn’t wait that long so he decided to make a similar open source version of it, with cheap off-the-shelf parts. The biggest difference is this one doesn’t have the music.

The build is quite simple and inexpensive. You’re looking at some PVC pipe, an Arduino Nano, a RGB LED, a 2.4GHz radio module, an accelerometer, a pingpong ball, a battery pack, and various other resistors and wire. Nothing to it really! All the source code, and instructions are available off of [Juerd’s] site, and he’s done a great job explaining everything, down to fixing a common problem that some people have on Arduino Nanos!

Stick around after the break to see how the original Johann Sebastian Joust game works!

35 thoughts on “Opentilt: Tag, You’re Out!

  1. I don’t get it. What are they trying to do? I see people slapping each other’s hands, holding what looks like ice cream cones or something in their other hand – then what?

  2. I don’t get why people ask if you’ve heard of something and assume you haven’t, like that’s some badge of pride. I actually have heard of Johann Sebastian Joust, so it just makes you look ignorant when you assume I haven’t…

      1. I haven’t read the article but from the video it seems fairly obvious to me. The music tempo sets an acceleration limit. When the acceleration limit is surpassed the light on your baton reduces to show you’ve lost a “life”.

        Fast music, you can move fast, slow music you must move slow. The object is to be the last-man-standing, by way of getting your opponents to break the acceleration limit, either by “spooking” them into jerking, or physically hitting their baton, or of course they might be moving fast and then the music suddenly slows and they get “caught out”.

          1. yes, then someone pushes you and kicks your ‘baton’ away and you lose.

            so i understand the game now, but i dont understand the game WITHOUT the music… maybe the if LEDs blink faster or slower as an indicator?

    1. The devices tend to fall and hit walls, so I’m not sure expensive smart phones would be such a great idea. I don’t know how you get smartphones at “basically zero” cost, but mine cost significantly more than that ;-) There has been a smartphone variant of this game, but it appears not to be available any more. It was called “Papa Quash”.

      Besides that, the light from a smartphone screen is hard too see at extreme angles.

    1. The controllers are very sensitive, and if you move too violently, you will trigger your own as well as your oppenent’s. So violent behaviour won’t let you win this game unless :-)

  3. Here is another open source version of it even less expensive than using smartphones (especially if we factor in costs of smashed smartphones): use plastic cups with water. Cost: almost zero.

    1. Indeed, but it makes it hard to tell who won. Our initial tests of Opentilt were just 10 lines of code or so, and did not have any RF communication. Although it was more or less playable, about a third of the games would end in us not knowing who was tagged last.

      Now I’m not saying that you couldn’t add electronics to your cups of water, of course. In fact, I’d love to see that hack!

  4. I’ve played Johann Sebastian Joust, and it’s incredibly fun. Also, it can serve as a surprisingly effective ice breaker at parties, especially if there’s alcohol in the mix.

    And FYI, it would be challenging to get hurt/injure someone playing this game unless you were really being an asshole.

      1. Actually, since they’re PWM pins, a mere boolean negation can’t fix that. Instead, just change the analogWrite(pin, x) calls to analogWrite(pin, 255 – x). The main reason for using CC was utter laziness: the GND pin is close to the PWM pins… :-)

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