Introduction

Centaur wireless network is the part of the system that senses the monitored phenomena, collects and propagates the data from the field to Centaur cloud platform. The wireless network is composed by:

– Wireless sensor devices (i.e. end nodes)

– Wireless network extenders (repeaters)

– Wireless sensor network and internet gateway (i.e. WSN/GSM Gateway)
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One-off Network Infrastructure Setup

Follow the next steps to setup a wireless sensor network infrastructure through which the wireless sensor devices will communicate their data to the gateway:

1) Unpack and assemble the GSM gateway and connect the wireless sensor gateway though a USB port.

2) If the area to be covered is large, wireless network extenders should be used. In that case the extenders must be scattered around the area and be plugged on main power using their USB power supply.
3) If the GSM gateway is configured correctly, it should appear on Centaur cloud platform in section: Devices -> Gateways as shown below
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4) Once the GSM/Wireless sensor gateway is functional click on the “Details” on the left column to get inside the gateway’s control panel
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5) Activate the sensors close to the gateway (in the same room) one-by-one and wait until they start appearing in the “Overview” tab. The default communication interval is set to 120 seconds (2 minutes)
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6) If the whole number of the activated sensors are activated and appearing on the “Overview” tab of the gateway, place the sensors inside the facilities that are to be monitored. Wait for the network to rebuild the broken links and dynamically create the new mesh. The final step is to configure the sleep interval in order to put the wireless network in normal operation mode. As normal operation mode is considered the suggested sleep period which is 10800 seconds, or 3 hours. To set the network to normal operation click on the “_Commands” tab
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To get the current sleep period of the network select the “SLEEP PERIOD” from the AT Commands window and press the “Get” button. If the command is executed successfully the sleep period should appear in the “Response” window
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7) To set the normal operation mode sleep period press the SLEEP PERIOD button again, set the Value to 10800 and press the “SEND” button
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Press the “SLEEP PERIOD” and “GET” buttons again to get the current sleep period of the wireless network. If the 3-hour sleep period was set successfully, this get procedure should return “10800” in the Response window
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The Wireless Network

In the next images you can see the building blocks of Centaur’s wireless sensor network

The End Device

The End Device is a wireless electronic circuit, based on a  programmable tranceiver (XBee) which will create a self-organizing wireless network with its gateway, and/or other neighboring nodes. The end-device will measure Phosphine (Ph3) concentration in the air, based on a sensor cell located at the top of the device. Apart from the PH3 sensor, the device has  embedded temperature sensor.

The Xbee gateway

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USB connection to the GSM/internet gateway