I am designing an LED light panel with 80 diodes at 4 v power drop and 20 ma forward current + 180 diodes at 3 v and 20 ma. I am not sure where to go from here to figure out what driver or power converter to use to power up my light panel. Can someone direct me on how I calculate this?

 

Hello,

What will be the voltage of the used power supply?
You can calculate the needed resistor with the following formula:
R = (Vsupply - Vled) / Iled
Vled may be the summation of a couple of leds in series.
For safety the voltage accross the resistor must be at least 2 Volts, for better regulation.

Bill_Marsden has written a nice thread for the use of leds:
.LEDs, 555s, Flashers, and Light Chasers

Bertus