This document covers the usage and technical details of the Motion Sensor platform developed at the Alexandra Institute during 2008-2010 by Jesper Nielsen and Jacob Andersen. The document is comprised of two parts: a user guide part containing an introduction to the platform including basic information on how to program the microcontrollers, and an in-depth technical reference part.
The wireless sensor board top and bottom view, and the USB stick.
The Motion Sensor platform is made up of two device types: a wireless sensor board and a USB stick capable of forming wireless networks. This following sections introduce the two device types.
The sensor board is basically a tiny computer with sensing capabilities, a wireless networking device, a couple of buttons, and LEDs. All of this has been designed with low-power technology, in order to keep the power consumption as low as possible.
The sensor board's power supply is a single coin cell, and a well-designed application may be capable of running for months or even years on a single battery.
A battery test can be performed by pressing both buttons and releasing the "Reset" button first. In case the battery level is (still) OK, both LEDs will light up for a couple of seconds. If the battery level is low either one or no LED will light up. Furthermore, the LED intensity will provide a hint about the battery level. A clear bright light indicates a fresh battery while a very dim light will indicate a battery approaching the end of its life.
The USB stick is used as a bridge between an ordinary computer and the wireless network of sensor devices.
The guides and manuals listed below introduce the Motion Sensor platform at a level of detail appropriate for the new user.
The hairy technical details of the platform can be divided into the following main themes: