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Forum Index : Microcontroller and PC projects : Offline Retro Radio with PicoMite
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javavi Guru  Joined: 01/10/2023 Location: UkrainePosts: 542 |
 This is offline radio project that plays early 20th century records in random order, without the ability to switch or skip tracks. Like a real AM radio. To assemble the device, you need a Raspberry Pi Pico, a MicroSD card, an amplifier, 100 kOhm volume control with on-off switch and a 10cm speaker. Optionally, you can add a lithium battery and a TP4056 charging board to your project. The player program is written in PicoMite MMBasic. All songs must be placed in the WAV folder in the root of the memory card. Files naming from 0001.wav to 9999.wav. I recommend MS ADPCM 22050Hz 4-bit mono WAVE format. Optionally, you can create a folder with radio jingles called Jingles. In which you can also place files named from 0001.wav to 9999.wav. If the program finds jingles on the memory card, it plays them randomly once every 5-10 songs. I attached the jingles I created to the project files. https://www.thingiverse.com/ This is a project of one of my community comrades whom I suggested to make this retro "radio" on PicoMite MMBasic Edited 2026-03-14 20:14 by javavi |
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| javavi Guru Joined: 01/10/2023 Location: UkrainePosts: 542 |
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Martin H. Guru Joined: 04/06/2022 Location: GermanyPosts: 1441 |
That's a nice idea  surely you could extend that to MP3 on the PICO2 as well.This means you can fit more music onto the SD card and loading times are reduced'no comment |
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| bfwolf Senior Member  Joined: 03/01/2025 Location: GermanyPosts: 208 |
It would be perfect if you could also additionally add an FM tuner module (e.g., with I2C bus control). There are some very inexpensive ones available with the RDA5807M or Si4702/Si4703 chips. https://www.roboter-bausatz.de/p/fm-stereo-radio-rda5807m-funkmodul Then it would be a "real radio."  |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 5823 |
Hi Javavi, First of all, how good of you to promote MMBasic. Maybe from your community we can see more projects comming in this forum. Thank you. You suggested ADPCM 4bits 22kHz. Is that selected to minimize files size ? Have you tried FLAC audio @ 16kHz ? Picomite will adapt the PWM frequency to match the 16kHz (either 32 or 48). I am just curious, since I did not do any tests, and would like to learn from you. Volhout Edited 2026-03-15 18:21 by Volhout PicomiteVGA PETSCII ROBOTS |
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| javavi Guru Joined: 01/10/2023 Location: UkrainePosts: 542 |
This is a project of one of my community comrades whom I suggested to make this retro "radio" on PicoMite MMBasic, рe decided to do this project on Pico RP2040, of which he has a lot, and for this reason the MP3 format was not considered. I suggested using re-encoded music in FLAC format, but he decided that this project should reproduce monophonic audio with the quality of AM receivers of those years, and this is what he replied: It turns out PicoMite can handle not only PCM but also ADPCM files very well in WAV format. This allowed me to convert tracks to 22050Hz 4-bit mono MS ADPCM, averaging 2-2.5MB per song, in pretty good quality for a desktop radio station. So, offline MP3 radio turned out to be unnecessary for my project. The quality of recordings from the first half of the 20th century rarely reaches the limitations of this format, so I'm happy. Thanks for the tips. Now I'm starting to design the body.  There was also a proposal to build into this radio a “green eye” for tuning, like in old vacuum tube radios. Yes, it can be done, but I think the point of this "radio" is the atmosphere the user is counting on when turning it on, and therefore the music here should be selected accordingly. Edited 2026-03-15 18:55 by javavi |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 8727 |
An official Pico, using it's built in switcher supply, would be great for battery operation here. Even better if the clock speed can be reduced a bit. Two or three AA cells will run them for ages. It'll be the amp that takes most of the power and a class D mono like a PAM8032A would be ideal as it will work down to 2V like the Pico. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| DaveC5 Newbie  Joined: 24/09/2025 Location: United KingdomPosts: 34 |
Lovely! Adding MP3 would just need the Pico swapping for a Pico 2, so an easy upgrade any to do any time you wanted. |
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