Introduction

The Rundfunker is a tabletop mp3 player that scans the WLAN for local audio sources and is able to play shared audio-files. It has a built-in 2-way speaker system, a LCD display and a very simple yet powerful user interface. The device is independent of any external peripheral equipment - all hardware components are integrated into the appealingly designed housing including an exclusive aluminium front panel. All you need is 12 V DC power supplied e.g. by a mains adapter. The Rundfunker is driven by various parts we developed from scratch - such as a customized Linux, operating software implemented in Java and a circuit board for connection of hardware (LCD display and buttons). The idea of the Rundfunker was born at the FH Augsburg, University of Applied Sciences. Our 5-man team (Mathias Bauer, Christoph Beckmann, Christian Leberfinger, Stefan Loibl, Jan Peuker) has designed and implemented the entire software and has made it available as open source. Moreover we constructed two fully functional prototypes - all in all we worked about 5 months on this project.

The idea of developing a WLAN radio emerged from the desire to combine the advantages of a FM receiver with those of a personalised collection of music on a PC. A FM receiver usually is compact, portable and uncomplicated in use. Unfortunately the programme of the radio stations is not everyone's cup of tea. The mp3 files on a personal computer could be an alternative, however they have the huge drawback of normally being located on a more or less immobile computer. Thus they can hardly be heard beyond the four walls of the room the PC stands in (without annoying the neighbours).

Our Rundfunker is an elegant solution for this circumstance. It is a radio-shaped mp3 player that offers wireless access to all mp3s that are shared in the local network and thus isn't subject to the volume-restrictions of the popular mp3 USB sticks with unhandy tiny buttons that nowadays have a capacity of only few gigabytes. Via WLAN the Rundfunker can deal with huge audio-libraries with hypothetically unlimited size.

Rundfunker is mobile, yet not made for real portable use like Walkman and co - it shows its strength within the reach of the wireless home network: The device doesn't have to make do with an ultra-compact housing like an iPod, but consists of a cubic box (dimensions: 21×21×18 centimeters) that holds enough volume for the integrated 2-way speaker system, an exclusive aluminium front panel containing easy to use buttons and a clearly arranged LCD display.

A typical use case for the Rundfunker would be: the study in the upper floor has a PC with a hard disk filled with your most precious and well-sorted songs e.g. recorded from your old vinyl records. Your Rundfunker is situated in your kitchen and can play these mp3s via WLAN. The listener has various possibilities of influencing the playback. By means of the easy to use interface he can choose his favourite album or genre or simply browse through the entire collection of mp3s.

A power supply is the only thing you need to take the Rundfunker into operation. To enable the Rundfunker to play your songs, you can use the comfortable web interface and configure your IP-address and your shared audio-sources. You can also use the Java-Applet in the web interface to operate your Rundfunker by remote control.

Motherboard

We decided to use a completely passively cooled VIA EPIA motherboard. We agreed on buying the MS 10000E LVDS, because it offers serial and audio ports shaped as pin headers, a PCI slot and has a built in compact-flash connector that we use to boot Troubadix, our specially customized Knoppix derivative. Unfortunately, the 12V DC-DC ATX power supply unit we ordered didn't fit onto the board, because it interfered with the massive cooler of our EPIA. We first thought of using an ATX power extension, but fortunately our university's locksmith was able to perfectly mill the cooler the way we needed it. WLAN connectivity is offered by a PCI card - having quite a big antenna on the Rundfunker's side was our very intention and fixing it directly to the PCI card was the easiest way to achieve this aim.