Letibee Island

Table of Contents

1. Introduction
2. Objectives
3. WSAN description
4. Nodes position
5. Nodes measurements
6. Regularized map

Introduction

This document describes how to setup the SENSEI Letibee based island.

Objectives

The network at CEA-Leti provides information to an end-user located at a gateway or through the Sensei platform. These information are

• Nodes position
• Average value of a measure done at each node side (ie luminance or temperature)
• An estimated map of the measure done at each node side.

Figure 1 : CEA WSAN + Gateway for Sensei

The WSAN activities do not use standardized communication protocols. Due to this constraint the communication with a node is not direct but through a virtual connection managed by a gateway (ie : a more powerful node included in the network).

Datamanager

The datamanager is a standalone software which have the following objectives:

• Gather frames received on the usb port from the Letibee WSN
• Put data into database tables (rssi and position - see below)
• Remove older data if a time limit is specified

Database

The database is a MySQL database. The script below create the tables and the rows useful for the datamanager and the gateway.

CREATE DATABASE sensei;
USE sensei;

CREATE TABLE rssi (TxNodeId double);
ALTER TABLE rssi ADD (RxNodeId double);
ALTER TABLE rssi ADD (Rssi double);
ALTER TABLE rssi ADD (RelativeTime double);
ALTER TABLE rssi ADD (Time time);
ALTER TABLE rssi ADD (Date date);

CREATE TABLE position (NodeId double);
ALTER TABLE position ADD (PositionX double);
ALTER TABLE position ADD (PositionY double);
ALTER TABLE position ADD (Time time);
ALTER TABLE position ADD (Date date);

CREATE TABLE measTemperature (NodeId double);
ALTER TABLE measTemperature ADD (Temperature double);
ALTER TABLE measTemperature ADD (RelativeTime double);
ALTER TABLE measTemperature ADD (Time time);
ALTER TABLE measTemperature ADD (Date date);

CREATE TABLE measLuminance (NodeId double);
ALTER TABLE measLuminance ADD (Luminance double);
ALTER TABLE measLuminance ADD (RelativeTime double);
ALTER TABLE measLuminance ADD (Time time);
ALTER TABLE measLuminance ADD (Date date);

CREATE TABLE regmapOut (Type text);
ALTER TABLE regmapOut ADD (RefPositionX double);
ALTER TABLE regmapOut ADD (RefPositionY double);
ALTER TABLE regmapOut ADD (Value double);
ALTER TABLE regmapOut ADD (PositionX double);
ALTER TABLE regmapOut ADD (PositionY double);
ALTER TABLE regmapOut ADD (Time time);
ALTER TABLE regmapOut ADD (Date date)

Octave algorithms

Octave algorithms are used to compute rssi and position datas in order to generate more accurate positions datas and a regularized map. Different types of algorithm may be available.

Gateway

The Gateway task is to read on demand the information saved in DB tables and send these results by using the appropriate format to the end-user through the Sensei framework.

The LetiBee? plugin is based on a skeleton plugin and its HandleRequest? method. Most of datas are reachable using GET methods, each making a request to the database to get the up-to-date datas. Published datas are listed below.

Published datas:

The communication from the gateway to the end-user will be done using a text file. The Letibee WSAN is thinked like a geographic information database. This database contains nodes identities, positions (§Erreur : source de la référence non trouvée), measures and their histories (§Erreur : source de la référence non trouvée), estimate of others positions values using any kind of algorithms (§Erreur : source de la référence non trouvée). All these information will be send through the Sensei framework using the appropriate protocol and xml format.

WSAN description

Resource description

Sensors

/letibee/nodes

This resource returns the number of nodes in the letibee network and their identities.

Nodes position

Resource description Sensors /letibee/[nodeid]/[position]

Where position = positionX, positionY

This resource returns the position of the identified node

Nodes measurements

Resource description Sensors /letibee/[nodeid]/[scalar_sensor_type]

With scalar_sensor_type= luminance, temperature

This resource returns the measured value of the sensor and time reference for the considered node.

Regularized map

Resources description Sensors /letibee/regmap

This resource allows the user to choose between differents algorithms for computing the regmap, and the consensusStrength ; returns a VRML file (.wrl) (find a plugin here : ​http://cic.nist.gov/vrml/vbdetect.html)

Parameters

/letibee/mapdescription

This resource returns the name of the algorithm used to compute the last regmap.