Dimming an LED at a range of 1024 levels

Projects Programming
1

I would like to make a sketch that dims an LED at a range of 1024 levels. I know that i can use the analogWrite for dimming and it has the limitation of 256 levels, but i would like to know if there is a way around this

2

Yes
You can use TimerOne library.

// sketch_03_04_pwm
#include <TimerOne.h>
void setup() 
{
  pinMode(9, OUTPUT);   
  pinMode(10, OUTPUT);   
  Timer1.initialize(1000); //1kHz
  Timer1.pwm(9, 512);    //50%
  Timer1.pwm(10, 255);   //about 25%
}
 
void loop()
{
}

See programming Arduino Next steps. Page 66.
Period is 1000 uS or frequency is 1kHz.
Edit:
Affects pins 9 and 10, pin 9 here will have a square wave on it at 1kHz.
http://playground.arduino.cc/Code/Timer1

3

kookoo_gr:
dims an LED at a range of 1024 levels

Is this as a learning exercise? I'm struggling to image a situation where an observer would tell the difference between 256 levels let alone 1024 levels.

4

PeterH:

kookoo_gr:
dims an LED at a range of 1024 levels

Is this as a learning exercise? I'm struggling to image a situation where an observer would tell the difference between 256 levels let alone 1024 levels.

I agree.

If it is to do something like use an analogRead() value to set the brightness, use
the Arduino map() function to map the 0-1023 value to the 0-255 value used by analogWrite().
There is even an example of how to do this on the map() page:

--- bill

5

basically i want to make a project that uses a white LED strip in combination with a milky white plastic in order to create a white image so i can calibrate the images of a CCD camera. The range of 1024 is needed since various filters that i use need different levels of illumination and 256 levels won't cover this.

6

As you probably realize you can change the frequency in the "initialize" line and the width in the "pwm" line.
Timer1.initialize(1000); //1kHz
Timer1.pwm(9, 512); //50%