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Topic: LED Bulb (Read 1 time) previous topic - next topic

I am working on an Arduino controlled lamp project. I like the ease of dimming LEDs with PWM so I want to use an LED light bulb. However, they are all designed to plug into a 120V AC lamp. Has anyone over taken one of these LED bulbs apart. Would it be easy to control them and power them with 12V?

winner10920

Easiest would be to buy a 10w led off ebay for 6$, then buy a 5$ 10w led driver with an enable pin you can pwm
but as for those I've opened one up before but ended up putting it back together
I imagine you may have to cut off the led itself and make a new driver, it has a little transformer to drop the voltage then a circuit to condition that to dc at the appropriate voltage level for the led, probably designed for constant power not being switched
you could switch the led maybe from that driver but I doubt the constant current part will like its output being taken away and put back 800 times a second

Grumpy_Mike

Quote
Would it be easy to control them and power them with 12V?

No.


Easiest would be to buy a 10w led off ebay for 6$, then buy a 5$ 10w led driver with an enable pin you can pwm
but as for those I've opened one up before but ended up putting it back together
I imagine you may have to cut off the led itself and make a new driver, it has a little transformer to drop the voltage then a circuit to condition that to dc at the appropriate voltage level for the led, probably designed for constant power not being switched
you could switch the led maybe from that driver but I doubt the constant current part will like its output being taken away and put back 800 times a second


I was leaning towards something like your 10W idea. However, I want a nice diffused desklamp, so that is why I was starting to look into the bulbs. Another idea I was was do have three 3W LEDs mounted in a circle, but I am afraid I may get hot spots with this setup.

winner10920

If you ever see a broken/used lcd in the garbage, grab it
behind the screen are a couple sheets of plastic and disffusers that work great for stuff like this, usually 15 minutes worth of taking apart but its worth it for free


If you ever see a broken/used lcd in the garbage, grab it
behind the screen are a couple sheets of plastic and disffusers that work great for stuff like this, usually 15 minutes worth of taking apart but its worth it for free


Hmmm that sounds pretty interesting. So there is a sheet of material that I could use to diffuse my clustered LEDs? Or should I used the actual backlight LED from the LCD?

winner10920

Yes, actual sheets that'll difuse pretty well
I haven't taken apart an led tv yet, just the regular fluorescent ones, led may be different

kf2qd

#7
May 11, 2012, 07:24 pm Last Edit: May 11, 2012, 07:27 pm by kf2qd Reason: 1
Check around the various parts suppliers - I got 100 WHite LEDs from DIPMicro (may not have in stock, They seem to handle surplus type buys on some of their items) and build your own LED lamp. I have 1 group of 16 (4 rows of 4 LEDs ) that I have connected to an old computer batery (12V) and makes an impressive flashlight. When you can get a bunch of LEDs for pennies apiece you can experiment.

Currently at DIPMicro - 100 white LED for 5.29, 200 for 9.76 US.

winner10920

Or 1w leds off ebay, proba. Can get 10 for 3$, they are wide angle and you'll never see a spot,


Yes, actual sheets that'll difuse pretty well
I haven't taken apart an led tv yet, just the regular fluorescent ones, led may be different


I like that idea a lot. Are there any readily available materials that would behave similarly that I wouldn't have to scavenge from calculators and such? I am approaching this project like a production design.

winner10920

Idk, but lol not calculators, im talking about like 42" lcd tv's
giant sheets that are easy to cut with scissors to any size u want


Idk, but lol not calculators, im talking about like 42" lcd tv's
giant sheets that are easy to cut with scissors to any size u want


Oh yea I like the idea of 42" sheets alot better haha

Chagrin

The little star LEDs don't have a hot spot problem. I have a desk lamp with two 1W LEDs -- no diffuser -- and the light looks great.

winner10920

The only leds that I have stocked are those 1w ones, I buy them on ebay sometime 10 for a dollar, and there are decently bright if you put them full power, or work well less powered as a nice soft indicator light

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