Streaming My Consciousness

The biggest electrical energy drain in your home is usually lights. It goes without saying that if you can address that area, you’ll be a whole lot happier when the electric bill comes.

To this end, we’ve been replacing the lights in our home, starting with CFL a few years ago.Rather than an all-out replacement campaign, we simply replaced bulbs as they went out, under the premise that those are the ones that are on most of the time, and consequently consume more energy. There are several lights in our house that are incandescent, but are rarely used. As such, changing them is not a cost-effective proposition, given the higher cost of the bulbs. There are other areas in the house that are on dimmers, so CFL was not an option there.

One area where I absolutely love the CFL’s usually annoying habit of having to warm up to full brightness over a few minutes? The master bathroom. The overhead light there needs to be reasonably bright, but first thing in the morning, a 100W bulb is an assault on the senses. The 13W CFL there now warms up gently (slower on colder mornings) and isn’t quite so rough when you wake up.

Even CFL bulbs have a limited lifetime (about 2-3x that of incandescents), so those are starting to die now, and need to be replaced. Disposal of fluorescent lights is problematic due to a number of toxic substances involved. Over the past few years, LED bulbs have become a much more mature technology, and the price has come down substantially. Most residential LED bulbs are expected to last 20 years.

Where I’m using LED bulbs in my house:

Kitchen Track Lighting. Gradually replacing the eight halogen GU10 bulbs. So far, I’ve got three 4W Philips LED bulbs from Home Depot ($30). They’re just as bright as the 50W halogens, and they don’t emit any IR to speak of (the halogens would melt butter on the counter!). Net Cost savings over the 10-year lifetime of eight bulbs: around $1500.

Master Bedroom. Just got a set of four Dimmable 8W LED lamps from LED Liquidators (please ignore the horrible web design – it seems to be a common problem with online LED retailers) that claim to be equivalent to 60W. These go in the ceiling fan and are ideally suited to that application – they’re on a lot, on a dimmer, and the fan has a lot of vibration, which is really hard on incandescents. Net cost savings over 20-year lifetime of the bulbs: $800.

And if you’re into that sort of thing, it also reduces your carbon footprint.

For the last couple of years, we’ve used LED Christmas lights in our sanctuary. Considering how many we have (hundreds), the electricity savings are probably non-trivial.

All our LED strings in the sanctuary are plugged into either a stage dimmer or, where a dimmer port was unavailable, an Elation UniBar hooked into an RC4 Magic wireless DMX receiver (with the transmitter wired into DMX up in the catwalks). This allows us to control the Christmas lights along with the rest of the theatrical lighting via the Hog. It’s a very nice setup.

The other day, when Frank was running the stream, he saw the Christmas lights were fading in and out in sequence, and called up to the Penalty Box (the plexiglass-wrapped area at the back of house where the lighting operator and worship producer sit) and asked them to quit playing with the lights. As it turns out, they weren’t and the lights were all on. Mysteriously, they were fading in and out in sequence on the wide shot camera. When we looked at them on one of the other remote cameras, everything looked normal.

Then it hit me. I went to the remote control on the wide camera and cranked down the shutter speed, and lo, the lights gradually came together until they were all on. This is what it looked like:

Most stage dimmers operate by switching the AC cycle on and off via pulse width modulation. LEDs then only show one half of the AC sine wave, making them strobe, effectively reproducing the square-wave pulses that are modulating the dimmers. What We were seeing on the cameras was a beat frequency of the camera’s shutter speed and the strobing of the LEDs. You don’t see this on incandescent lighting because of the thermal persistence of the filaments. But why were the lights cycling at different times? Each one was connected to a different dimmer circuit, and those circuits are spread among the three AC phases coming into the dimmer room (which has a monster 2000-amp breaker).

So, if you’re shooting video of anything that has LED lights in it, make sure your shutter speed is at 1/60, or the lights are going to start acting strangely.