Jasper's Retro Internet Radio - Feb-2018
I gave new life to an old Vendomatic FM/AM transitor radio of at least 30 years by replacing the electronics with Raspberry Pi Zer0 W to make it a Wi-Fi connected digital music player. It plays music from internet radio stations, from my local NAS using DLNA, and it even plays music from Spotify. I wanted to make it look as original as possible. Fom the outside you can't see it has been hacked. First I removed the old transformer and all the componentsfrom the PCB to give a flat surface to mount the new electronics to. Then I added a AC to USB power adapter, I had to use a saw to make it fit. Then I added the Raspberry Pi and mounted it using tie wraps, and not hot glue because that may melt when the radio heats up in the sun. The Rapsberry Pi was placed such that I could acces the SD card from a hole in the battery compartment behind the cover. I connected a cheap USB soundcard using a very tiny micro USB to female USB A plug. I used a 3.5mm audio connector and two 4k7 series resistor to turn the stereo signal into mono, which in turn I wired to a 1 channel 2.5W class D amplifier (Adafruit PAM8302). The amplifier was powered from 5V from the Raspberry Pi. I found the original speaker was broken, that was probably the reason the old radio stopped working in the passed. The old 0.5W speaker was replaced by a 4W Visaton speaker (Visaton SC 5.9 ND). I tried re-using the original power/volume dial but I could not get the volume control to work so well and I didn't bother to replace the original potentiometer with a new one. The tuning dial is still shifting the frequency indicator but it is not function.
Finally I put open source software Volumio on the SD card in the Raspberry Pi. It's great, because it automatically sets up an hotspot so you can easily set the credentials for the Wi-Fi network. After that setting up Volumio is easy; you just need to go to a webpage using the local web address http://volumio.local and follow the setup guide. Volumio is great because it automatically detects music from my NAS using DLNA. The radio can be controlled from an app on a mobile device or from a webpage in the local network. I installed a AutoPlay plugin so it automatically starts playing internet radio on power-on. There's a cool GPIO plugin available for Volumio, so you can connect push buttons for basic on/off, volume, play/pause, prev/next control. I did not implent the push buttons because I wanted the radio to look original, besides the radio can be controlled from a mobile device anyway. I have also tried other open source software like pimusicbox but I found Volumio easiest to use, especially with setting up the Wifi connection. The USB sound card does not have the best audio quality but that's OK because the wideband speaker isn't great either and the radio still sounds lo-fi as before, or slightly better.
