Retro Pi World Radio

By Rosemary Hattersley. Posted

Most of the maker-interviewees who feature in The MagPi’s project showcase pages have a deep love of technology and, often, a career in computing. Retro Pi World Radio creator Raju Salubramanian is just such a fellow, but he is also on a mission to teach the next generation to code: something that exactly chimes with why Raspberry Pi exists in the first place.

Raju describes himself as an AFOL (adult fan of LEGO) and, as well as building his own Optimus Prime, Hulkbuster and other complex kits, he has used the brightly-coloured bricks in his mission to teach his kids and their friends how to code. He does this as a ‘coach’ for the FIRST LEGO League ( in his home town of San Jose, California. He is almost as big a fan of Raspberry Pi as he is of LEGO, with multiple projects under his belt and six Raspberry Pi boards in use around his home (not all disclosed to his partner!).

Despite his thoroughly modern career as a software engineer in Silicon Valley and a CV that lists VMware and Google among his credits, Raju has a fondness for the old days. “I have always loved to tinker and repurpose old hardware to build something new”, he says, favouring Raspberry Pi boards because they are “perfect” for the projects he likes to work on since “they are so easy to setup and get started with”.

Python handles the GPIO input from the rotary knobs and converts it into keyboard input events, such as scrolling for radio stations

A nod to nostalgia

For the retro radio build Raju wanted something that would force us to slow down in our current fast-paced digital world. He says the analogue controls of the radio are in some way the opposite of how we interact with our devices today with touch and voice. The project was also meant to remind Raju of his childhood of using analogue knobs to change stations. His lengthy search for the ideal old radio eventually led to him choosing one with a speaker to one side and enough space to cut out a window and fit a new 5in screen. His Retro World Radio can tune in to a vast collection of internet streaming radio stations from around the globe, and features a vintage map to browse and find radio streams.

He posted a video of his project on YouTube showing station selection

Keep on improving

Raju had seen other retro radio upcycling projects online, and was particularly keen on creating one similar to this internet radio project. He used a 2GB Raspberry Pi 4 because he “needed the extra horsepower of Raspberry Pi 4 to get experience with the map display”. He bought the main components from online stores such as Adafruit.

Sourcing a suitable radio and writing the software interface were his main challenges, since backend engineering is his professional forte. “I enjoyed the experience of writing all the Javascript code for the display and I am still thinking of ways to improve the overall aesthetic. Raju designed the new parts  himself including a new front face for the radio, using CAD software to design and create some 3D-printed parts. He also wrote software for the Retro World Radio, making liberal use of existing SDKs and open source or free online libraries.

The searchable Radio Garden site serves up stations from around the globe

He began with a development platform using a breadboard, which allowed him to test the software. The first version had three rotary knobs mapped to Raspberry Pi’s GPIO pins, but Raju later decided to use four knobs. These pull in internet streams from Radio.Garden and can be chosen by location as well as genre.

Having completed the radio project, Raju is now gearing up to combine his love of tinkering with tech with LEGO, and has recently acquired a Raspberry Pi Zero W.

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