ERCIM News No.47, October 2001 [contents]

Enabling Ambient Intelligence Research with SoapBox Platform

by Esa Tuulari

One approach for ambient intelligence research is to study what happens as sensing, computing and wireless communication capabilities are added to everyday objects. At VTT Electronics scientists have designed and implemented SoapBox, Sensing, Operating and Activating Peripheral Box, which makes this approach possible.

SoapBox is put together from commercial components. It possesses small size, low power consumption, RF-communication in unlicenced radio-band and a set of in-built sensors. It also has IO capabilities to connect to user devices. As user devices we use mainly PDA’s which nowadays offer decent support for application development. However, using a PC or laptop is also possible.

By installing SoapBoxes in everyday objects we really can have computers everywhere. With the wireless communication link all these computers are continuously connected to the user device, enhancing user-real world communication to entirely new level compared to situation with no such system or systems based solely on existing commercial devices (see Figure 2).

SoapBox architecture
Figure 1. SoapBox architecture consisting of one central Box attached to the user device (in the back of the Palm, not shown) and several remote Boxes locating in the environment.
Figure 2: Enhancing user - real world interaction. Left: Original situation.
Centre: Cellular phone alone doesn’t help much.
Right: Adding SoapBoxes in both ends solves the problem.
Figure 3: Picture of SoapBox boards, illustrating the size and shape of the electronics.

From the devices point-of-view also the user is part of the environment. In the SoapBox architecture we can easily instrument the user with SoapBoxes. For example measuring and recognicing user activity and user behaviour is much easier if the sensors are distributed in the limbs than concentrated in the belt or back, as is the situation with many wearable computers.

Application Examples
In general it is very easy to invent and implement new applications based on SoapBoxes. For example sensing if doors are open or closed, if someones chair has moved lately, or if there are lot of traffic in the corridor offer a basic set of applications that can be implemented with SoapBoxes.

By installing a SoapBox in the ceiling of a mailbox we can use the proximity sensor for detecting letters (or anything similar) inserted in the mailbox. The SoapBox then transmits an RF-message indicating “new mail available”. If the owner of the mailbox is nearby with his PDA and central SoapBox attached to it, the message is received and the user is informed about new mail. In a factory or a store the possibility to monitor the usage of for example fork-lifts could provide valuable information. With the SoapBox this can be done without installing any tags or cameras in the building. Instrumenting the moving object is enough to start with.

Short range wireless communication is one of the key features of the SoapBox. The challenge has been to combine low power consumption and such performance parameters as communication range, bit rate and message delay. Luckily in many applications high bit rate is not needed since only short messages are used and time between messages is rather long. SoapBox electronics consists of two printed circuit boards (see Figure 3), one containing the sensors and the other containing all the other electronics. This makes it easy to develop further versions in a modular fashion.

SoapBox software has been implemented mainly in C language. A few lines of assembly language has been used mainly in timing critical parts. All the application software can be written in C, utilizing the API offering services for RF- ans RS-communication as well as for reading sensors. A single channel 868 MHz radio is used for two way, half duplex wireless communication. A small helical antenna fits inside the SoapBox encapsulation. Maximum data rate is 10 kbps and maximum transmit power is 1 mW. A real-time clock and calendar circuit is also included. It can be utilized for example for timing control functions and for recording timestamps for detected events. The sensor board of SoapBox ver. 1.0 includes four different kinds of sensors:

  • Three axis acceleration sensors. These sensors can be used to measure acceleration or tilt of the device
  • Illumination sensor. The intensity of visible light can be measured. The dynamic range of the sensor enables both indoor and outdoor measurements
  • Electronic compass can be used for sensing the direction of the Box and also for detecting magnetic objects
  • Optical proximity sensor for measuring relative distances. This sensor is based on sending IR pulses and measuring the intensity of reflected light.

This work has been partially conducted in European joint research project ‘Beyond the GUI’ under ITEA cluster project of the EUREKA network, and financially supported by TEKES (Technology Development Centre Finland), to which organisations the author wish to express his gratitude.


Please contact:
Esa Tuulari - VTT Electronics
Tel: +358 8 551 2334
E-mail: esa.tuulari@vtt.fi