In this senior project I design and develop software for the Raspberry Pi which allows the user to listen to and control a scanner radio anywhere in their home. The solution involves utilizing a Raspberry Pi 2 interfaced with the radio, a software package to communicate directly with the radio, and a web app hosting a web client providing the interface for user control. Audio streaming is achieved through the use of FFmpeg. Listening on the client is achieved by using an external software such as Video Lan (VLC) to open the audio stream. We provide an operable proof-of-concept with less than 1-second of latency.
The hardware used for this project includes: a radio scanner, Raspberry Pi 2 and a USB sound adapter. As shown in figure 1, the Raspberry Pi is connected to the local area network via the on board Ethernet and to the scanner via an USB cable. The USB sound card is connected to the Raspberry Pi to allow for capture of audio. The external speaker port of the scanner is connected to the microphone on the sound card via 3.5mm cable.
We considered various operating systems for the Raspberry Pi including: Raspberian, Ubuntu, Ubuntu Snappy, and Windows IoT. We choose a community supported image of Ubuntu 14.04 for compatibility with existing software packages and user familiarity. You can read more about available operating systems in Appendix C.
This project enables scanner listeners to improve their listening experience by removing the physical limitation usually associated scanning. It provides remote scanner control and audio streaming with low latency. It is designed to allow improvement and expand ability and is usable from desktop and mobile clients.
Source: California Polytechnic State University
Author: Jackson Marshall Strand