Freeform Circuit Expert Jiří Praus Wears His LED Heart on His Sleeve — or Anywhere Else

Developer and soldering enthusiast Jiří Praus has completed another freeform circuit build, constructing an badge in the shape of a heart using addressable LEDs, an ATtiny85 microcontroller, LiPo battery, and a series of brass wires — but no underlying PCB.

Regular readers will be familiar with Praus' novel approach to circuit building: Rather than taking the relatively simple route of printed a PCB, Praus instead constructs his circuits from solid brass wire — creating everything from animated snowflakes to, most impressively, a PCB-less Arduino Uno microcontroller board dubbed the Freeduino.

Now, Praus has completed his latest build: a freeform heart badge, based around the WS2812b addressable LED and an ATtiny85 microcontroller. "This time I built an LED heart badge that features an array of programmable LEDs," Praus writes. "LEDs are controlled with tiny ATtiny85 embedded on the back. The whole sculpture is very compact and easy to wear."

A rough build log on his Twitter account shows the process of construction, with Praus designing and using a 3D-printed template to keep the LEDs in alignment as the lengths of brass wire are soldered to each in turn. A 3D printer is also employed for the creation of a custom enclosure which houses a 1,000mAh battery and charging board — the only PCB in the design — which makes the badge wholly wearable and capable of running for 10 hours per charge.

Those interested in building their own can find the source code for the project in a GitHub gist, while a bill of materials is available in the description on Praus' YouTube video.