Repo of documents and code used for the Mediator M40 Radio upgrade

The Mediator M40 radio is a tube radio manufactured in the early 1940s by the Swiss Company Mediator located in La Chaux-de-Fonds. The radio is identical to the Philips Philette 206 A made by Philips Switzerland. However it differs from the Philips 206 A produced in the Netherlands as it only has MW. My radio has a control mark sticker from the Swiss telecom PTT from 1941 on the back.

• Service Manual of the Philips 206 A 'Junior'

The radio is upgraded to a Webradio and Music Player using a Raspberry Pi Zero W and a HifiBerry MiniAMP. The electrical components of the radio are very old and even if it seems that most of them still work, I decided to leave them in as is, but not to use them in the circuit. However I wanted to reuse the control knobs including the corresponding potentiometer and variable capacitor and the speaker.

The Linux based volumio is used as OS and music player software, as it has nice features and works on the Raspberry Pi Zero. The HifiBerryOS does not work well on Pi Zero according their website.

Download and install volumio according the documentation.

Note: When using the HifiBerry MiniAMP HifiBerry DAC need to be selected as Playback Output Device. However make sure that I2S DAC is not enabled.

The original 'Waverange' switch of the radio is used as power switch. To allow a proper shutdown the OnOff SHIM by pimoroni is used. The OnOff SHIM is usually used with a button and not a switch, therefore I had to modify the clean-shutdown code to shutdwon, when the trigger is pulled high (Pull-Up) and not low.

The original volume control knob is used for volume control. The potentiometer is connected to an MCP3008 A/D converter. The MCP3008 is connected to tha Raspberry Pi using the SPI interface. A volume-control daemon is installed on the Pi (src/analog_input/volume_daemon.py)

TBD