Choosing the right white LEDs for my dawn simulator
I'm playing around with a simple DIY dawn simulator alarm clock. I've got a prototype thing working on a breadboard; an ATMEGA88 sends a PWM signal, which fades in a white LED. Adding more LEDs, I thought I'd better send the PWM signal through a mosfet, rather than drive the LEDs directly.
Now I have 5 LEDs, which I grabbed in a pack at the local gadget store. However, looking at LED dawn simulators, it seems I'll need an 6x12 array of LEDs to actually wake someone up. Before I buy bulk online, I was hoping someone might help me choose the right components :)
What I want is,
- white LEDs
- I guess large is better? what I have now is 10mm
- should they be ultra-bright?