I’ve seen plenty of DIY electronics projects that make you go “wtf, why” (this Bluetooth speaker in a walnut comes to mind) but this battery-to-Bluetooth-speaker conversion sits in a completely different category. Someone actually spent two weeks gutting a battery casing, drilling 60 precision sound holes, and cramming a full Bluetooth speaker setup inside what used to house alkaline cells. The kicker? It actually sounds good. Like, surprisingly good for something that began life as a Duracell knockoff with a pink bunny on the wrapper.
Before we get into the technical gymnastics here, let’s appreciate the sheer absurdity of the starting point. This maker didn’t just crack open the battery and start drilling. They built a makeshift fan out of a toy car motor, some blue electrical tape, and a propeller to safely drain the thing over three days. Three full days of waiting for a janky desk fan to suck the last electrons out of a battery so they could avoid turning their workspace into a lithium fire hazard. That’s either extreme patience or mild insanity, and honestly, I respect both.
Designer: Slivki Show
The disassembly process alone is wild. They started with thin drill bits, worked up to thicker ones, then had to break out a rotary tool with high carbon steel bits because apparently battery casings are tougher than anyone expects. There’s this moment where they wrap the whole thing in tape to catch metal fragments, put on a rubber glove like they’re defusing a bomb, and start yanking out the battery core with pliers. Then they’re scraping out the guts with a popsicle stick. A popsicle stick! The juxtaposition of power tools and wooden sticks is somehow perfect. After excavating all the alkaline nastiness inside, they cleaned everything with alcohol like they were prepping for surgery.
Here’s where it gets legitimately impressive though. The sound holes could’ve been a disaster. Their first attempt with a ruler looked terrible, so instead of accepting wonky holes, they 3D printed a custom drilling template with 60 perfectly aligned holes and reinforced guiding channels to lock the drill bit in place. One millimeter of drift would mean starting over, so they zip-tied and hot-glued this template down like their life depended on it. When it came off, those holes were lined up in perfect rows. That’s the kind of problem-solving that separates people who tinker from people who actually engineer solutions. You physically cannot achieve that precision by hand.
The electronics work is where most hobbyist projects die, but this one survived. Six dollar Bluetooth circuit board, tiny speaker, mini battery, push button, LEDs for power and charging indicators. Sounds simple until you’re trying to desolder 1mm LEDs with a soldering iron tip so massive you can barely see what you’re doing. They literally describe it as “nearly impossible to make out what was happening” with their naked eyes. Yet somehow those microscopic components got wired up without burning anything out. The layout planning involved printing a Photoshop design onto masking tape to create a sticky template for drilling button and port holes. That’s the kind of creative workflow hack you develop after years of building stuff and learning what actually works.
Final assembly required UV-curing glue (the dental filling type), a 3D-printed speaker sleeve, and strategic decisions about not permanently bonding everything so future repairs stay possible. The bottom cover snaps on like the original battery cap. Two weeks of work produced a Bluetooth speaker that fits in your palm and actually sounds good. The metal casing could’ve made it sound terrible, but the acoustics somehow worked out. Would I do this myself? Probably not. Do I respect the hell out of someone who spent 72 hours draining a battery with a homemade fan just to start this journey? Absolutely.
The post Someone Hollowed Out a Duracell Battery and Fit a Surprisingly Good Bluetooth Speaker Inside first appeared on Yanko Design.