We all know how to open a box, but what if the box doesn’t want to be opened?

You are geocaching and found the cache. It’s slightly open but every time you get close, the mysterious chest locks itself. As you look around you see some strange objects blinking. Soon you notice that each object is reacting with your moves but there are far too many objects to activate all of them at the same time on your own. So if you don’t have a partner with you, go home or look for one, because you are playing TeamTwist.

What is it?

When playing TeamTwist you have to interact with the strange objects, called widgets. To finally open the chest, you have to activate different widgets depending on the current level. After each level the chest opens itself a little bit further.

After twisting yourself more and more from level to level, the chest is finally willing to let you raise its treasure.

How does it work?

The game consists of the chest and several widgets.

The chest

In an old sparkling wine box in we placed two servos: One for lifting the lid and the other to lock the box. Our first prototype (as you see in the video) was just a shoe box. Furthermore the box is secured by a light barrier (ultrasonic sensor) which prevents people to approach it before the end of the game.

The widgets

Although there are lots of possibilities to construct the widgets, we decided to build four different kinds of widgets for a start.

Each widget is featured with LEDs that blink when trying to attract the players attention. But they shine continuously when the player handles the widget the right way.

Human Conducting widget
Form a chain, linking both parts of the widget.
This widget consists of two nearly identical parts. Each part has a large contactor area composed of multiple stripes of copper tape (Yes, we use the players as conducting medium, but we hope that our test persons are still alive and well). One contactor is supplied with 5V whereas the other one has just a “sensor line-out” to measure the incoming current, telling us whether the players are electrified (a connection between both parts).

Light Widget
Shade or illuminate it e.g. by directing the cup to a light source.
We used plastic cups in which we placed a LDR and a layer of kitchen foil to scatter the incident light.

Weight Widget
Put a heavy object on it e.g. your partner.
Our first prototype consisted of the following layers (bottom to top): floor pads, acryl glass, FSR (Force Sensing Resistor), a layer of rubber to enlarge the working surface of the sensor and again acrylic glass. Since this was too slippery for Sebastian’s shoes we applied large snippets of the evil-smelling rubber blanket we found in the workshop. And it worked pretty well!

Distance Widget
Get close or keep away.
We fitted an infra-red distance sensor into an acryl glass triangle.

The coding

The game cycle is shown in the diagram below.

Further Ideas

TeamTwist can be easily extended by adding new or other widgets. Further widgets could be:

  • a spirit level widget, which must be held in a certain direction
  • an object, that has to be squashed or stretched

Lessons learned

Construct something that fits into a single movable box which doesn’t depend on the location for the final presentation: It took us the whole last day to extend the wires of the widgets to prepare the TeamTwist arena – lost crucial time for polishing and preventing heavy malfunctions.