Software Defined Radio on the Raspberry Pi

There’s a range of cheap (< $20) USB Digital TV receivers that due to their wide tuning range can be used as Software Defined Radios (SDR) when combined with other software to tune and receive the signal from the dongle.

RTL chipset dongles are supported by open source software rtl-sdr. Download the source to your Pi and build following the instructions on their website. By running as follows:

rtl_tcp -a your_ip_address

you can stream the data received from the dongle inserted into your Pi to other software running elsewhere (your desktop/laptop) like SDR Sharp (by pointing it to the IP address of the Pi) which you can use to control the tuning of the dongle.

Deploying a Maven-based web project from Eclipse

Here’s the problem: you start with a Web project in Eclipse, created via one of the Wizards. At some point you convert it to a Maven project, but when you deploy the project from Eclipse, your web content in /src/main/webapp is not deployed, because Eclipse is not aware of the Maven folder structure.

I’ve done this multiple times in the past and usually work out a way to build a ear/war and manually deploy it to my server or via a script instead, because I can’t work out how to get a converted project to deploy in Eclipse 🙂

The magic to get this to work is to add the maven-war-plugin to your Maven pom.xml file:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-war-plugin</artifactId>
    <version>2.3</version>
    <configuration>
        <failOnMissingWebXml>false</failOnMissingWebXml>
    </configuration>
</plugin>

 

EE7 Maven Dependencies

<dependency> 
    <groupId>javax</groupId>   
     <artifactId>javaee-api</artifactId>   
     <version>7.0</version> 
 </dependency>

Further details here for specific EE7 technologies.

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