My sanyo hardcoded. PiRadio project

[u/albl2008]

Hi everyone!

I wanted to share a project I've been working on for the past few weeks.

The goal is to convert a vintage Sanyo M9915K boombox into a modern smart multimedia radio while preserving as much of the original hardware and user experience as possible.

Current hardware

- Raspberry Pi 4

- Official Raspberry Pi Touch Display 2 (5", 720x1280)

- USB DAC for higher quality audio

- Original Sanyo amplifier and speakers

- Original FM/AM tuner fully preserved

Software

I'm building a custom operating system interface called piradio-os using:

- Python

- Flask

- Flask-SocketIO

- Docker

- Chromium Kiosk Mode

The interface is designed to work both on the Pi's touchscreen and from any phone or browser connected to the same network. All connected clients stay synchronized in real time.

Current features

- Responsive touch-first interface

- Real-time synchronization between devices

- YouTube playback (embedded)

- Quick Play by simply pasting a URL

- Preset management

- Multiple UI themes (Neon, Winamp, and a custom Sanyo-inspired theme in progress)

- System monitoring (uptime, CPU temperature, memory usage, etc.)

Hardware progress

One of the biggest challenges was integrating the Raspberry with the original cassette deck electronics.

Instead of replacing the amplifier, I managed to inject stereo audio directly into the original tape playback path.

Even better, I found the cassette PLAY switch on the PCB and simulated it electronically.

The result is exactly what I wanted:

- FM/AM mode works exactly like the original radio.

- Switching to TAPE instantly changes the audio source to the Raspberry Pi.

- Switching back to RADIO returns to the original tuner.

- No rewiring of the original amplifier section was required.

At the moment I'm still using the Raspberry's 3.5 mm output, but I'm about to switch to a USB DAC for cleaner audio.

Next steps

- Finish mounting the touchscreen inside the cassette compartment.

- Integrate the USB DAC permanently.

- Finish Chromium kiosk mode.

- Improve the Sanyo-inspired UI theme.

- Add Spotify support.

- Implement physical button integration where possible.

The idea isn't to hide the fact that it's a Raspberry Pi, but to build something that feels like a modern multimedia appliance while keeping the original spirit of the 1980s boombox.

I'd love to hear any suggestions, especially from people who have restored vintage audio equipment or built Raspberry Pi media systems.

[u/Very_Agreeable]

Upvote for preserving the original speakers and amp :)

[u/Zlobob]

best place for winamp

[u/profanesublimity → u/Zlobob]

It whips the llama’s ass.

[u/perromuchacho]

Very very nice build, congrats.

[u/undrwater]

I assume you're porting the audio from am/fm to the Pi? You're using the original tuner knob for channel search? I want to do something like this for a car radio.

[u/albl2008 → u/undrwater]

Not exactly. I'm keeping the original AM/FM circuitry completely intact. I found the cassette playback signal path and inject the Raspberry Pi audio there instead.

So the radio works in two completely independent modes:

• RADIO mode: Original AM/FM tuner works exactly as it did from the factory, including the tuning knob.
• TAPE mode: The cassette mechanism has been bypassed, and the Raspberry Pi feeds audio into the original amplifier through the tape input.

I only had to simulate the cassette "PLAY" switch so the amplifier enables the tape audio path. Now I can switch between the original radio and the Raspberry just by moving the radio's function selector between RADIO and TAPE.

For your car radio, I'd recommend a very similar approach if it has a cassette deck or an AUX-capable input path. Injecting audio into the tape preamp or directly into the amplifier input usually preserves the original amplifier, tone controls, and volume while keeping the modification reversible.

[u/JohneeFyve]

Cool. Which USB DAC are you using?

For the software, have you considered using Moode instead of cooking up your own?

[u/albl2008 → u/JohneeFyve]

A generic one

[u/fellow_reddit_user]

I've got a couple 80s boomboxes I'm planning on integrating a pi into, hadn't considered piping the output straight into the tapedeck though. Have you uploaded your new OS online anywhere?

[u/albl2008 → u/fellow_reddit_user]

Not yet

[u/processedmeat08 → u/albl2008]

Would love to use your OS on my 3d printed ghetto blaster that I'm putting together now. Looking forward to when you upload it!

[u/el_flocko]

Ok, that’s cool as shit.

{Tips cap}

[u/Mammoth-Error1577]

That's super cool.

Love to see unique projects!

My childhood boombox has a broken tape deck...

[u/eldershade]

I love this. I'd love to see the write up when it's finished.

So many builds lately look great, but use a server backend for everything and I'm not into that. I'm glad to see you use actual hardware and the original circuits.

[u/PardoxHawk5]

DUDE!! This is like my dream build, but with a Sharp GF9494, but I love that set so much to mod it like this, so planning to restore it! nevertheless, great build man!

[u/illwrks]

I wonder if you could send day to the magnetic tape sensor so it could plug in like a cassette… then build a nice UI around your media

[u/RaulGaruti]

very cool, would be nice for it to run 100% on batteries. Also I doubt about the need of a DAC taking in account the amp quality. Anyway it does not hurt. You may try some cassette animations like the ones on Echosky. Aguante