This document covers the usage and technical details of the DUL Radio platform developed at the Alexandra Institute during 2008-2012 by Jesper Nielsen and Jacob Andersen for the Center for Digital Urban Living. 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 DUL Radio platform is made up of two device types: a wireless sensor board and a USB stick capable of forming wireless networks. The 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 a couple of red light emitting diodes (LEDs). All of this has been designed to keep the power consumption as low as possible.
The sensor board's power supply is a single coin cell. A well-designed application may be capable of running for months or even years on the energy available from 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 primary purpose of the USB stick is to be used as a bridge between an ordinary computer (the host) and the wireless network of sensor devices. Furthermore, in many applications the stick may assume a role as some kind of network coordinator, as it is powered by the host computer and therefore has plenty of energy resources available (compared to the coin cell driven sensor boards).
The guides and manuals listed below introduce the DUL Radio 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: