Internet radios have been a thing in some form for the last quarter century, and the advent of cheap networked microcontrollers has made them easier than ever to build. But just how small can one be made? [Milen] has made one that’s about as small as we’ve seen, and put it up on Instructables.
The hardware recipe is straightforward enough; take a microcontroller, connect it to the internet, and have your internet radio software squirt its output to a DAC. In this case the microcontroller is an ESP32-C£ on a very small dev board, and clipped to that is a custom PCB with a PCM5102A I2S DAC and an amplifier. The whole thing is tiny, small enough in fact that the two connectors are significant in size compared to it.
Whether or not it’s a practical device for listening remains to be seen, but it’s certainly tiny. But the question is, could it be made smaller? Perhaps eschewing the connectors would be an easy win, and in return for a loss in quality the ESP has a built-in DAC that’s not intended for audio but can be used. If you have any bright ideas, we’d be interested to hear them.
We’ve seen plenty of internet radios over the years, and for some reason this cassette-shaped one appeals to us.
That’s very neat.
You could lose the DAC by using the ESP32-S3 supermini and buffer transistors but you still need to mount the headphone socket so it would not be smaller.
use a mobile phone speaker and a passive amplifier (horn). ja ja in 3D
https://www.etsy.com/market/horn_phone_amplifier
Why not use a MCU with Bluetooth built-in and eliminate the need for the DAC and headphones socket?
You can reduce it to a single chip if you continue to remove functionality. This thing depends on other devices for channel selection, volume control, power and producing sound waves.
Cute hack! A long way since mp3-chips on the parallell port decoding data from ancient PC.
The ESP32 can output spdif on most ports, so you can just connect an LED and feed the light into a spdif audio converter. I put an ESP32 with squeezebox firmware into a cheap Chinese spdif converter box, to make it a squeezebox radio that you can use with headphones or connect to a sound bar. If your board already has a software controllable LED, you can use even that to send out audio.
What’s a “ESP32-C£”. I’ve heard of C3 and C6 variants.