Stage Lighting Hack Keeps La Bohème From Becoming A Dumpster Fire

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.

19 thoughts on “Stage Lighting Hack Keeps La Bohème From Becoming A Dumpster Fire

  1. A bit difficult to really tell much from the clip. but kudos if it works in dim lighting!

    I like a little bit of small local theater and get a kick from seeing a nice set piece.
    If you like hacking, and on a budget?, and with an (fairly affordably) paying public doing the appraisal?
    Get involved with local theater, it can be “interesting”. Just getting in on set building days gets you a chance to meet and join in with some other folks who often have to do some pretty cool re-purposing of many things.
    and yes.. that can be a little tough some times (volunteer work). But a good audience just somehow makes it feel worth it.

    I think the worst fake “flames” have to be those trifling lights with the wig-wagging plastic tab over an LED. Was at relatives house and tried to sleep on the couch in a room with the fake candles.
    It felt more like I was stopped at a “license check”, as the police here refer to those fishing events.
    Headache inducing. Very annoying things to be around.

    Now can someone tell me why there are so many movie scenes showing open flames being shown with the video run in reverse? Typically noticed in older Western films.

    1. Actually did that volunteer with the theater thing I’d do it again but not with some companies.

      It certainly gets interesting however. In my time there I went from carpentry heres a drill do this like so now do it 6 more times for the set to lighting heres the lighting board and heres how to turn shit on to follow the manager to get accomidations for the new pianist sorted since the last one messed up their arm. I got to make a bed during that expedition!

      Would not. Work for some of the outfits that go through that theater. Its the Darwin awards I swear who gets to purify the genepool. My father who works at the theater had to tell them no you cant have extremely dry dead leaves but 2 feet away directly in-front the burning hot light. That is a bad idea and this was last week! Not their worse! Certainly “interesting” indeed.

      From my experience working once as a minion for an opera figure out if someone has their shit together before you just volunteer.
      I was lucky with getting someone who actually knew what they were doing and could know where they were after doing a lap of their fishbowl.
      Keep that in mind prospective minions.

      1. God send to all of you who volunteer to make productions happen. I wish I could say that as a career all of those problems go away, they don’t. Most of my colleagues over the years have been phenomenal, but there are some production companies I won’t work with again. Some because of how they treat people, some because I don’t want to be a part of someone getting hurt.

    1. You can begin to understand why there were so many “great fires” before the advent of electric light, not to mention heating and cooking that didn’t involve an open fire inside a house

    1. Probably not, a lot of decorative off the shelf effects are what we cognitively think it looks like, but when we try to use those solutions on stage they usually read poorly.

      In addition I knew what I had on hand. We did have someone out looking for materials for an alternate solution, but this build went shockingly quickly and ended up giving the lighting designer and myself much more control of how it would fit the scene. I wish I had better footage.

    2. Many of those effects are designed around what we think something looks like, but they rarely read well when put on stage. We also didn’t have them on hand to try. We did have someone out shopping for materials for a different option. The reason this ended up working so well is because the designer and I could look at it in context, adjust the timings, intensity, and color temperature to fit the look of the scene.

    3. A fan in front of a HPS light looks too much like fire. Color and flicker tickle the ‘alert’ part of human brains.

      I found this when still growing indoors, under lights.
      Covered it, so my neighbors wouldn’t call the fire department.
      Would have been double plus ungood.

  2. Many years ago I made a burning log effect for a fireplace scene. 6×12 array of WS2812 LEDs fed from an OctoWS2812 board and Teensy. The Teensy listened to DMX512 and would change the intensity and speed of the fire effect from a couple of channels. More recently, I made a Teensy 4.1 based ArtNet to WS2812 and DMX node.

  3. You can install the FastLED library in Arduino, and there’s a several example sketches to control these Neopixels. One of them is a decent fire effect, another called Pacifica has a really nice, slow moving blue wave effect. Super easy to get a strip of LED lights working with no programming.

  4. There was a typo, I didn’t have pixels. Fortunately I had 5-in-1 RGBWwCw LED tape. I think the neopixel effects are cool, but if you are obscuring the light source and just getting the combined output of all of the LEDs then they blend together into something less dynamic than might be imagined. I was fortunate to have an LED tape with a low color temperature warm white. It built the backbone of the overall color output.

    It was much faster to build a few random generated values, as well as add a mechanism to manipulate the variables quickly to tune the output, then it would have been to google and try flashing multiple existing effects and test them. I also gained the abilities mentioned to use green as a constrained value of red to increase the warmth while maintaining realism, and to have the ability to use the constrain() command to bias the timing value to manipulate the flicker. I could change the upper and lower biasing values put into the random variable created for the flicker timing (I thought I had shared the github on the project page, but it seems I missed that. It’s been added to the description).

    So the timing value between intensity changes could be between 0 and 100ms, but I ended up with biasing values of -1000 and 200 that were used to generate the timing, then that value used constrain() to force it to be within 0-100 (a constrain value of -1000 was kind of weird, and meant that my random timing command could have been improved, but when we got it looking good it was best to leave it as is. So instead of a equal chance to get any value between 0 and 100ms it ended up having its value skewed heavily shorter. (I really like the constrain and map functions for this kind of application, I have a fun little neopixel color changer at home where I do random hue and saturation values, but use constrain and map to bias towards more saturated. I still get some really nice pale colors, but am a bit more likely to see saturated colors then a whole lot of just mixed pastels.)

    The actual code that controls the LEDs is only a couple dozen lines. I had a few minutes while dress rehearsal was actively happening on stage to add a serial input that let me quickly try out different variables for the timing and color intensity choices before hard coding them and uploading to the board. This turned out to save a ton of time when we had a few minutes to look at the effect in context and find good values.

  5. As a technical person, I remember being quite impressed with the creative solutions the drama students came up with. At school, one play required a camp fire lighting effect. The drama student took a 3 channel sound to light unit. (Basically a low, mids, high filter… to level detector, to lamp dimmer) changed out the globes to white, red and yellow. And taped a Walkman to it. The earphones against the sound to light’s mic. Choose your track, and done.

  6. When i worked in a theater about 15 years ago we would use those neon light starters to get normal tungsten bulbs to flicker. 3 starters and 3 bulbs for some randomization. We used them for campfires, BBQs and Chimneys on Stage with som Red and Orange Gels.

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