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### Topic: LED luminous intensity - need help (Read 3540 times)previous topic - next topic

#### manteliukasx

##### Oct 22, 2012, 12:33 pm
Hello. I want to know about LED luminous intesity. Maybe some one can explain about it in easy way, not scientifically.
Also i have some questions:
Is enought 1000 leds with 1500mcd luminous intensity to light up room(3.5mx4m)?
does these leds light negatively effect eyes?
The bigger led view angle the better is lighting, isnt it?
If i use resistor with each diode it will make lesser current usege?
And the last one, is good to make led light for room?

#1
##### Oct 22, 2012, 02:52 pm
1000? Why not use fewer but with higher output?
These are really bright
http://www.dipmicro.com/store/LED5W
Make a couple of panels with LEDs behind some kind of diffuser to avoid looking at them directly and place around the room.
Yes, need a current limit resistor with each one to limit current to 20mA.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

#### manteliukasx

#2
##### Oct 22, 2012, 03:18 pm
i want to do so because this will be my room light and led matrix

#3
##### Oct 22, 2012, 05:41 pm
What is the layout of your matrix? Example: 32x32? 10 x 100? 8 x 125? 16 x 62?
32x32 probably most efficienct - 4 shift registers along each side.
4 along the "side" of the matrix sourcing 20mA pf current to the 32 anodes of each row,
and 4 along the "bottom" of the matrix controlling 32 transistors to sink 640mA from each column, one column at a time.
Spread the LEDs out however you'd like.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

#### manteliukasx

#4
##### Oct 22, 2012, 07:46 pm
about 30x32 and i know how to control matrix, only idk how to make controllable led brightness with arduino. And my questions was Is enought 1000 leds with 1500mcd luminous intensity to light up room or i need to byt one 150w lamp?

#5
##### Oct 22, 2012, 09:17 pm
I don't know - try an experimet with 10, see how it looks.
I do know the LEDs I mentioned are blindingly bright, I was testing with just 3 and had to bring the current down to 3-4 mA and still not look directly at them in my living room.
You can control the brightness by using PWM on the cathode drivers, for 0-255 levels of brightness control.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

#6
thank you

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