

How to build a Smart Lightbulb in a Weekend - rgonzalez
http://blog.kytelabs.com/?p=55

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hmottestad
It's very pretty they put everything into the shell of the bulb. My smart bulb
is a regular led lamp that I've run the power through a nice transistor and
arduino sitting next to the lamp on my desk. However I have a nice webapp and
even a brightness sensor to adapt to light in the room.

Some videos of my lamp: [http://fluffyelephant.com/2012/09/two-videos-about-
my-led-la...](http://fluffyelephant.com/2012/09/two-videos-about-my-led-lamp/)

And a write-up: <http://fluffyelephant.com/2012/05/lamp-update/>

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BHSPitMonkey
In case the videos aren't working for other people, too, here are the direct
YouTube links:

* <http://www.youtube.com/watch?v=xHFkA9gsG0Y>

* <http://www.youtube.com/watch?v=_glWFDGBJq0>

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hmottestad
Thanks for posting this. I'm the author and I would be very grateful if you
could give me a bit more details about what wasn't working about the videos so
I can fix the problem.

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BHSPitMonkey
When I visited your links, the plugin you use for embedding the videos was
failing, replacing the videos with an error message. I peeked at the page
source and found the YouTube video IDs there. It seems to be working now.

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hmottestad
Thanks.

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makomk
Is the Arduino really necessary here? From the description, it appears to be
basically equivalent to 3 wires between the Bluetooth module running the
actual control code and the transistors switching the LEDs. (Honestly,
Arduinos seem to be a bit overused in general...)

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Falling3
From the article:

"Right now, the Arduino isn’t reading serial data from the BLE module, it’s
pretty much working as a pass-through for whatever the BLE module says. It
reads the value of three of the BLE’s GPIO’s to control each color of the
LEDs. In the future, it should read serial commands from the UART and have a
big list of awesome things that it’ll do. Naturally."

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stephengillie
Neat shortcut -- instead of building your own main-to-5v power converter, you
found the best one made by someone else and just used it.

Edit: I just realized you're basically some code away from reinventing LIFX.
[http://www.kickstarter.com/projects/limemouse/lifx-the-
light...](http://www.kickstarter.com/projects/limemouse/lifx-the-light-bulb-
reinvented)

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rgonzalez
Thanks!... Yeah, much more practical for a prototype.

Who says we are some code away? Stay tuned for the iPhone App blog post :)

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davidb_
Stuffing the iphone power supply into the lightbulb is interesting. I'm sure
if you took the time you could make/find a smaller switching power supply to
stuff in there, but using a well-designed, readily available power supply in
this kind of project is resourceful. I wouldn't have thought of it.

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nitrogen
This is a very cool project. How does it do on lumens per watt?

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jgonzalez
We're not sure how to calculate it but we did some crappy math and it got us
around 6.2 lumens per watt. Again, we're not sure if this is correct. You can
use the following datasheet if you'd like to calculate it yourself.
<http://www.adafruit.com/datasheets/FLR-100WAS-RGB.pdf>

Overall, it's decently bright but not as bright as a normal light bulb.

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nitrogen
If you're running them at full power, I calculated 9.9lm/W by adding the
typical mcd values (3700mcd), plugging them and the 50deg beam angle into [0]
to get 2.178 lumens, then dividing by the summed power rating (220mW). Of
course, this is ignoring the power used by the bluetooth module, Arduino, and
waste heat in the power supply.

For comparison, an incandescent bulb is 15lm/W, while the Hue bulbs are
70.6lm/W. So it's no Hue replacement, but still a cool, fun project.

[0] <http://led.linear1.org/lumen.wiz>

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rgonzalez
Thanks for the thorough calculations, it'll definitely help us moving forward.
Also, glad you mentioned Hue bulbs, we were focusing on Bluetooth as our main
differentiation factor but we have to cover the basic as well i.e. good
lighting.

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GotAnyMegadeth
I'm definitely going to do something like this

