How to build a Smart Lightbulb in a Weekend | Hacker News Reader

How to build a Smart Lightbulb in a Weekend

blog.kytelabs.com

44 pointsrgonzalez16 comments

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...

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

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

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.

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.

Thanks.

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...)

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."

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...

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

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

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.

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

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.

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

Thanks for the explanation :).

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.

I'm definitely going to do something like this

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