Ok so yes this is another led thread, but just bear with me, Ive done my homework and am almost ready to build, I just need to fine-tune my design.
I plan to make an led light panel using somewhere between 144-162 Red and Blue leds.
here are the specs:
RED
max forward current: 30ma ( I assume the recommended current would be 20ma?????)
forward voltage: 1.8-2.4v
BLUE:
max forward current: 30ma
forward voltage: 2.8-3.4v
I will be supplying the leds with 20v DC @ 350ma from a typical wall adaptor I have lying around that was actually originally intended to power leds.
Here is my first design:
http://www.flickr.com/photos/62746482@N02/5714922930/
and here is my second design:
http://www.flickr.com/photos/62746482@N02/5714922932/
obviously the overlap of copper strips will be seperated by a 'bridge' of rubber.
I think the 7 rows of red will eat more power and so a smaller resistor would be needed meaning less power wastage and less heat produced by the resistor? is this correct?
Because the specs for the voltages of the led vary I am having trouble calculating resistor value. a row of 6 red leds eats 10.8-14.4v while the blue row of 6 eats 16.8-20.4v
I crunched these numbers using ohms law and got resistor values for the red=470 ohm (@2veach) - 330 ohm (@2.3v)
Blue=82 ohm - 68 ohm
These were calculated with the leds using 20ma each.
Do you think I should be using larger resitsors eg 470 ohm or should I be using the weaker 330 ohm ones???
One more question: Can i, using the same design and power source make a panel that uses say 400 leds? My understanding is that it dosent matter how many banks/strips of leds you have as long as you dont use more than 6 blue leds in one strip and more than 8 leds in the red strip. Is this correct?
so yea, thats about it. What do you think?
I plan to make an led light panel using somewhere between 144-162 Red and Blue leds.
here are the specs:
RED
max forward current: 30ma ( I assume the recommended current would be 20ma?????)
forward voltage: 1.8-2.4v
BLUE:
max forward current: 30ma
forward voltage: 2.8-3.4v
I will be supplying the leds with 20v DC @ 350ma from a typical wall adaptor I have lying around that was actually originally intended to power leds.
Here is my first design:
http://www.flickr.com/photos/62746482@N02/5714922930/
and here is my second design:
http://www.flickr.com/photos/62746482@N02/5714922932/
obviously the overlap of copper strips will be seperated by a 'bridge' of rubber.
I think the 7 rows of red will eat more power and so a smaller resistor would be needed meaning less power wastage and less heat produced by the resistor? is this correct?
Because the specs for the voltages of the led vary I am having trouble calculating resistor value. a row of 6 red leds eats 10.8-14.4v while the blue row of 6 eats 16.8-20.4v
I crunched these numbers using ohms law and got resistor values for the red=470 ohm (@2veach) - 330 ohm (@2.3v)
Blue=82 ohm - 68 ohm
These were calculated with the leds using 20ma each.
Do you think I should be using larger resitsors eg 470 ohm or should I be using the weaker 330 ohm ones???
One more question: Can i, using the same design and power source make a panel that uses say 400 leds? My understanding is that it dosent matter how many banks/strips of leds you have as long as you dont use more than 6 blue leds in one strip and more than 8 leds in the red strip. Is this correct?
so yea, thats about it. What do you think?