I am a big fan of internet radio stations but it can be a bit restricting listening to my favourite stations on my laptop or phone. So over the last couple of weeks I have been building my own internet radio. A lot of people have converted old routers into radios but the best example I found was Bob Rathbones amazing Raspberry PI Radio. I had an old Raspberry Pi 2 lying around not doing much so I decided why not give it a try. Bob provides on his website an extremely comprehensive guide that takes you through the process of building an internet radio which if you’re interested you can download here.
At the heart of this radio is Music Player Daemon (MPD) running on Raspian Jessie. MPD is a flexible, powerful, server-side application for playing music. Through plugins and libraries it can play a variety of sound files while being controlled by its network protocol. Bobs manual provides a detailed overview of construction and software. It contains instructions for building the radio using either the HDD44780 LCD directly wired to the Raspberry PI GPIO pins or alternatively using an either an Adafruit RGB-backlit LCD plate or the PiFace Control and Display (CAD) . An I2C backpack is also now supported. It can be constructed using either push buttons or rotary encoders. An optional infra-red remote control can also be used. Along with the construction guidelines Bob also provides software to drive the LCD, read the switch states and interface with the MPD server.
When I started I had a pretty good idea of what I wanted to achieve with this radio. I wanted a 4×20 HDD44780 based LCD display, push buttons for control (rather than rotary encoders) and a pair of 4″ coaxial speakers. I wanted it to sound as good as possible so decided early on to use a Digital to Analogue Converter (DAC) rather than relying on the line level audio output on the Pi. A network connection would be via WiFi rather than a LAN connection. It would also have the ability to play music from an external USB device. Possible even the ability to control it with an old infra-red remote control.
The enclosure was constructed from 9mm MDF sheet. The dimensions of which were based around the two coaxial 4″ speakers and the LCD display. I didn’t want anything too big but I also didn’t want it so cramped inside that everything wasn’t going to fit.
Using Front Panel Designer I drew up a template to aid with the drilling of the holes for the speakers, the switches and the panel cut out for the display. The whole thing was then glued and joined with furniture blocks before being painted.
While in my local Maplin store I managed to bag a pair of 4″ Vible Slick Coaxial speakers from their clearance section for a good price. They fitted the bill perfectly. The speakers are driven via a 2x30W audio power amplifier kit from Velleman. The amplifier has an RMS output of 15W into 4 ohms and is protected against overheating and short circuits. The LCD display is driven directly by the GPIO lines of the Raspberry Pi. As are the switch inputs. In order to minimise the wiring somewhat I built a little interface board between the display, the switches and the header on the Raspberry Pi. I added a small potentiometer to the interface board to allow the overall volume to be configured.
Power for the Raspberry Pi is provided by the official mains power supply while the amplifier is powered via a 12V 50VA toroidal transformer. As I have already mentioned I wanted the radio to sound the best it possibly could so I opted to use the HifiBerry DAC+, a little expensive costing nearly as much as the Pi itself but it was definitely worth it. I am no audiophile but when driven hard those 4″ speakers sound great. With the addition of a panel mount USB socket music can also be played from a USB device.
Total spend is probably approaching well over £100, even already having the Raspberry Pi, but I am really pleased with the result. I have now have a fully up-gradable internet radio with around 600 stations configured that I can control remotely and sounds and looks amazing.