Sparton

For xmas this year my wife gave me an old Sparton radio from the late 1940s.

The radio was made by Sparton of Canada, based in London ON. This was the Canadian arm of the Sparks-Witherington company of Michigan and aside from making radios and kitchen appliances, it was also the presser and distributor for Columbia records from 1939-54 - they pressed the first stereo album in Canada. This particular radio model 4648 (manufactured 1946 & 47) has a glass tube with etched markings containing the tuning (AM band) and the whole thing is made out of heavy bakelite. It was not working.

The replacement guts contains an FM radio as well as bluetooth receiver connacted to a 20W amplifier which is all controlled by a raspberry pico microcontroller, so it is programmable; one feature request was to make CBC radio come on automatically in the morning and off a couple hours later - all mod cons available here. The AM display and glass tube were replaced with 14-segment LED displays; one dial now has an on/off and volume pot and the other is an 8-position rotary switch to select radio station.

The glass was replaced with a hunk of sanded plexiglass and the end result with the 8-character white LED display is kinda nixie-tube-like.

The software is written in Rust - there is no operating system at all running on the pico (#![no-std]) - when it starts up it jumps directly to the installed program. There is no hard drive, no network, no display, no keyboard, no packages, boxes, or bags. There is just enough flash memory to maintain the current settings, and the time is via a battery backed real time clock. Communication between amp, preamp (switch bluetooth / radio), radio, clock, and display is all via a serial I2C bus with a custom designed circuit board to tie it all together. The software is written and compiled on a mac and then downloaded to the pico and the debugging tools are excellent.

It looks pretty good in the kitchen.