Lifestyle meets technology. More and more fashion accessories contain electronics to allow for special effects. Together with Martin Bowtie I created and designed LED-illuminated bowties.

Bowtie: Firefly
Bowtie: Firefly

The design takes care, that the bowtie looks good too when switched off. Every single piece is hand-made. Slight variations in the design make every item unique.

The basic idea was to build a device that allows operation for at least two nights on a small coin cell battery. The bowties are cast in epoxy. This causes hard constraints connecting the power supply.

It was a real challenge, designing light effects in the epoxy in advance. The circuit was therefore designed to be re-programmable even when cast in epoxy.


The controller is based on an Atmel 25 tiny processor. It is able to control three groups of LEDs. Since IO-pins provide up to 40 mA, the LEDs are directly connected to the CPU pins via a resistor.

The first prototypes were built on a stripboard. The first series of simple PCBs was built with a PCB milling plotter. Later, more complex PCBs were build by a professional PCB service provider.

Up to now, three different models have been produced.


Red and yellow glass beads are arranged on leaf gold. They are lit by two groups of LEDs. The upper group flashes quickly (fire), the lower slowly (embers).


A black resin base is covered with glittering flakes. 18 LEDs in three groups are dimmed softly to mimic a star-lit night sky.


We created a bowtie resembling the Austrian flag for a special customer. The bowtie is based on the Firefly-PCB and the software for NightSky. Colored glass beads on leaf gold and silver assure a good look, even when switched off. Three LED groups illuminate the three colored areas.

Further development

I’ve got plenty of ideas. The limiting factor is the epoxy and the power supply. I am continuosly testing new concepts and try to find a way to build new and appealing effects.