Retro Bluetooth Speaker

What happens when a small speaker from a "free stuff" shelf collides with a leather-and-PVC gramophone horn tha I built two years ago? I copied an Instructables design (Leather Gramophone Horn, Passive Smart Phone Amplifier by velokenneth) almost exactly, leather horn and all, just replaced the copper tubing with PVC (lots cheaper). 

I was surprised how well it worked. Repurposing it as a bluetooth speaker was triggered by a small loudspeaker if found at the freebie shelf at Xerocraft. So I replaced the phone cradle with the speaker, wired in an ESP32 and a DAC / amplifier module and turned a century-old acoustic idea into a bluetooth wireless speaker. I finished it off with a volume pot and a tiny OLED display showing whatever's streaming. The project was built with a lot of help along the way with facilities and technical assistance at Xerocraft Maker Space in Tucson as well as guidance from Anthropic’s Claude AI for component suggestions, esp32 coding, and with this video itself.

You can see a YouTube video I'm made of the project here ...
 

Dan Davidson
July, 2026
dan@dantastic.us