VOIP

VOIP Processing Class

This virtual sensor implements a phone call notification. The virtual sensor makes a phone call when a condition in the virtual sensor query is triggered. The virtual sensor is configured to work with Asterisk. So, you will need to install or have an existing asterisk server running. To configure the sensor with asterisk you will need to add the following line:

#include extensions_gsn.conf

to the 'extensions_custom.conf' file in asterisk (/etc/asterisk/extensions_custom.conf). Once the virtual sensor is deployed, it automatically creates a dial plan in asterisk and registers extensions needed to make the phone calls, minimal configuration is required. This will include the any extensions created by the virtual sensor in the file 'extensions_gsn.conf'. Depending on the number of times the virtual sensor is deployed, an extension with the virtual sensor name and a random extension number (internal to asterisk) will be created. The virtual sensor uses the Manager API to connect (login) to asterisk and execute remote commands (e.g. load dial plan, make phone call, call forward). To login to the asterisk manager, you have to create an account and add your IP address in the 'manager.conf' file in asterisk (/etc/asterisk/manager.conf):

[testuser]
secret = mypassword
permit=192.168.12.101/255.255.0.0
read = system,call,log,verbose,command,agent,user
write = system,call,log,verbose,command,agent,user

Where, testuser is the username and secret is the password. In permit add your IP address (otherwise asterisk will block you). As part of asterisk, you will also need to install the 'festival' text to speech system (http://www.cstr.ed.ac.uk/projects/festival/) and the 'sox' utility (http://sox.sourceforge.net/). These programs are used by the virtual sensor to convert the notification message (string) to speech (audio) to be played by asterisk. If using linux/ubuntu, do an

apt-get install festival sox

Parameters:

• username Username to login to the asterisk server.
• password Password to login to the asterisk server.
• host DNS address of the asterisk server.
• number Telephone number to dial.
• message Notification message.

<virtual-sensor name="phone" priority="10">
	<processing-class>
	<class-name>gsn.vsensor.VoipVirtualSensor</class-name>
		<init-params>
			<param name="username">testuser</param>
			<param name="password">mypassword</param>
			<param name="host">asterisk-server.com</param>
			<param name="number">0041786831809</param>
			<param name="message">The temperature in the lab is too high.</param>
		</init-params>
		<output-structure>
			<field name="temperature" type="double" />
		</output-structure>
	</processing-class>
	<description>Makes a phone call when a query in the virtual sensor is satisfied.</description>
	<life-cycle pool-size="10" />
	<addressing>
		<predicate key=""></predicate>
	</addressing>
	<storage history-size="1h" />
  <streams>
    <stream name="input1">
    <source alias="source1" sampling-rate="1" storage-size="1">
      <address wrapper="multiformat">
          <predicate key="rate">5000</predicate>
      </address>
      <query>SELECT temperature, timed FROM wrapper WHERE packet_type=2</query>
    </source>
    <query>SELECT temperature, timed FROM source1</query>
    </stream> 
  </streams>
</virtual-sensor>