The combination of ambient and detailed information is important for displays in pervasive environments. We propose a parasol-type display called the “PhantomParasol” which can display both ambient and detailed information with smooth transition.
The PhantomParasol consists of LED arrays, a gyro sensor, and microcontrollers put at the rear side of a parasol. When a user of the PhantomParasol holds it still, he can obtain ambient information from the blinking patterns of LEDs. When he rotates the PhantomParasol, he can see detailed 2D images composed from moving blinking LEDs.

We developed a prototype PhantomParasol with the above concepts. The prototype system consists of a gyro sensor for detecting the rotation speed, LED arrays to display ambient and detailed information, and microcontrollers to control these devices (Fig. 3).
We attached eight LED arrays on the ribs with forty-five degree intervals. Each LED array consists of fifty-two LEDs and four demultiplexers1. We put a 1-axis gyro sensor2 on the handle of the parasol, and the output of the sensor is connected to the microcontroller through a 10-bit A/D converter. We attached microcontrollers3 on the ribs beside the LED arrays. Adjacent microcontrollers are connected serially, and exchange messages with each other. In addition, one of the microcontrollers (a host microcontroller) receives data from the gyro sensor, and exchanges commands (e.g. rewriting contents) with a host PC or a PDA via RS232C interface.

Fig. 4 shows a simple usage of the prototype system. When a user holds the PhantomParasol still, it presents ambient information with two LED arrays, just like the LED level meter of audio devices. If the user rotates the parasol, it presents weather forecast icons with all flashing LED arrays.

We can use the PhantomParasol for various real-world applications and entertainment use. Here, we show how we can use a PhantomParasol for route navigation.

When a user holds the PhantomParasol still, it can light one of the LED arrays to show the direction of his destination, and he can walk to the right direction to the destination. When he needs detailed information, he can see the map of the destination by rotating the parasol. He can obtain more detailed information by rotating the parasol more quickly (Fig. 6).
In this way, using the PhantomParasol, users can always perceive ambient information and obtain detailed information quickly if necessary.

• Koji Tsukada, Toshiyuki Masui: PhantomParasol: a parasol-type display
  transitioning from ambient to detailed，Adjunct Proceedings of Pervasive2006，pp.97-101 (May, 2006). [PDF]
• Japanese patent pending