Summary of STAGE LIGHTING HACK KEEPS LA BOHÈME FROM BECOMING A DUMPSTER FIRE
With wit and theater pragmatism, master electrician David Smith improved a distracting garbage-can fire effect for Utah Opera’s La bohème using a balled-up Neopixel strip, an Arduino, and MOSFET drivers. He limited colors to warm white, red, and green, randomized intensity and color via code, and diffused light with a printer-paper cylinder to hide holes. Two power circuits kept the Arduino running unseen while allowing dimmer-console control of the LEDs, producing a convincing, unobtrusive fire on stage.
Parts used in the La bohème garbage-can fire effect:
- Balled-up Neopixel LED strip
- Arduino microcontroller
- MOSFET drivers
- Printer paper cylinder (as diffuser and mounting)
- Two power circuits/cables (one for Arduino, one for LED tape)
- Dimmer console connection/control
- Greatly abused garbage can (prop)
With all due respect to the Utah Opera’s production of La bohème, we just couldn’t resist poking a little fun at master electrician [David Smith]’s quick lighting hack for the opera. And who knew an opera from 1896 would need a garbage can fire? Live and learn.
In what appears to be a case of “The show must go on,” [David] was called on to improve an existing fire effect for one scene in the opera, which was reportedly a bit “artificial and distracting.” This is a pretty common problem in live productions of all types; it’s easy to throw light at a problem, but it’s often hard to make it both convincing and unobtrusive. Luckily, he had both the time to come up with something, and a kit full of goodies to make it happen. A balled-up strip of Neopixels provided the light, with an Arduino running some simple code to randomize the intensity and color of the RGBs. [David] stuck with the warm white, red, and green colors, to keep the color temperature about right for a fire, and drove the LEDs with a couple of MOSFETs that he keeps in his kit to fix busted dimmer packs.
The overall effect worked well, but the holes knocked in the side of the greatly abused garbage can let too much light out, making the effect distracting on stage. The remedy was simple: a cylinder of printer paper surrounding the LED tape. The paper not only acted as a diffuser but held the tape in place inside the can. The electrical crew ran two circuits to the can — one to keep the Arduino running throughout the show, and one to power the LED tape. The former made sure the audience didn’t see the microcontroller boot sequence, and the latter gave the electrician a way to control the effect from the dimmer console. The brief video below shows it in action during a rehearsal.
Hats off to [David] and the whole crew for the stagecraft heroics and for getting this thrown together so quickly.
Source: STAGE LIGHTING HACK KEEPS LA BOHÈME FROM BECOMING A DUMPSTER FIRE
- What did David use to create the fire light effect?
He used a balled-up Neopixel LED strip driven by an Arduino with MOSFETs. - How was the LED color and intensity controlled?
The Arduino ran simple code to randomize intensity and color, limited to warm white, red, and green. - How did they prevent the audience from seeing the Arduino boot sequence?
They ran a dedicated power circuit to keep the Arduino running throughout the show. - How was the LED light diffusion achieved?
A cylinder of printer paper surrounded the LED tape to act as a diffuser and hold the tape in place. - How did the electrician control the effect during the show?
They powered the LED tape on a separate circuit tied into the dimmer console for control. - Why was a MOSFET used in the setup?
MOSFETs were used to drive the LEDs, using components the electrician keeps in his kit to fix busted dimmer packs. - Why were the colors limited to warm white, red, and green?
Those colors were chosen to keep the color temperature appropriate for a fire effect. - What problem did the printer paper solve besides diffusion?
It also held the LED tape in place inside the garbage can and blocked light from holes in the can.
