Most status LEDs on lab equipment do exactly one job: on, or off. James Bowman’s TermDriver 2 — a USB-to-serial interface from his company Excamera Labs, sold through Adafruit and Crowd Supply — spends real design effort making its status indicators do something closer to what an old incandescent panel light actually did: warm up, glow, and fade, rather than snap between two states.
Making an LCD act like a filament
TermDriver 2 monitors serial traffic across a wide range — 100 bit/s up to 2 Mbit/s — with live indicators for TX, RX, and the other signal lines, all rendered on its onboard LCD rather than through discrete LEDs. Bowman implemented a 16-step brightness gradient for each indicator, so a burst of activity ramps the glow up and lets it fade back down over time instead of flashing instantly on and off — deliberately mimicking the sluggish physical response of an incandescent bulb warming its filament. The indicator shapes themselves are drawn as superellipses rather than plain circles or squares, chosen specifically to recreate the soft, rounded look of plastic-covered panel lamps from Apollo-era spacecraft hardware. The practical payoff isn’t just nostalgia: a fading glow makes a single brief pulse of activity far easier to actually see and register than an instantaneous flash, which is often gone before your eye catches it.
Why it fits here
TermDriver 2 didn’t need any of this to work as a debugging tool — a plain on/off indicator would have done the job. That it got a genuinely considered piece of skeuomorphic design instead, applied to something as unglamorous as a serial-line activity light, is the kind of small, deliberate craft choice this site’s creative-hardware coverage keeps coming back to: function doesn’t have to be the whole story, even in a $30 piece of lab gear.