Arduino PWM to Android IOIO PWM

Question

I am working on a PWM project using the LED RGB LightStrips. I have the circuit built according to the link

http://www.ladyada.net/products/rgbledstrip/

Now I am trying to drop the Arduino and apply the Android IOIO board. My arduino code is as follows ...

void setup() {
pinMode(REDPIN, OUTPUT);
pinMode(GREENPIN, OUTPUT);
pinMode(BLUEPIN, OUTPUT);
}


void loop() {
  int r, g, b;

  // fade from blue to violet
  for (r = 0; r < 256; r++) { 
        analogWrite(REDPIN, r);
    delay(FADESPEED);
  } 
      // fade from violet to red
  for (b = 255; b > 0; b--) { 
                analogWrite(BLUEPIN, b);
        delay(FADESPEED);
          } 
  // fade from red to yellow
    for (g = 0; g < 256; g++) { 
    analogWrite(GREENPIN, g);
    delay(FADESPEED);
  } 
  // fade from yellow to green
  for (r = 255; r > 0; r--) { 
    analogWrite(REDPIN, r);
    delay(FADESPEED);
  } 
  // fade from green to teal
  for (b = 0; b < 256; b++) { 
    analogWrite(BLUEPIN, b);
    delay(FADESPEED);
  } 
  // fade from teal to blue
  for (g = 255; g > 0; g--) { 
    analogWrite(GREENPIN, g);
        delay(FADESPEED);
  } 
}

As I read about analogWrite for Arduino which is a max pwm of 255. Now when I plug in the IOIO board my code is as follows

public void setup() throws ConnectionLostException {
        try {

            blueOutput_ = ioio_.openPwmOutput(14, 490);
            led_ = ioio_.openDigitalOutput(IOIO.LED_PIN, true);
            enableUi(true);
        } catch (ConnectionLostException e) {
            enableUi(false);
            throw e;
        }
public void loop() throws ConnectionLostException {

            try {

                blueOutput_.setPulseWidth(seekBlue.getProgress());

                led_.write(!toggle.isChecked());
                sleep(10);

            } catch (InterruptedException e) {
                ioio_.disconnect();
            } catch (ConnectionLostException e) {
                enableUi(false);
                throw e;
            }
        }
    }

Notice I have the frequency matched with the Arduino and IOIO at 490 Hz. Now when I output a PWM mod on the pin 14, the LED begins to light up but maxes out way before it is near its max brightness. If I increase the PWM above 255, the intensity of the blue (and red and green) does not increase. I have 12V into the RGB Light strip with is a length of 3 LED Lights (roughly 1.75" for testing purposes)

Is there a reason I cannot get the same response from the IOIO as the Arduino? Thank You.

Ytai Ytai · Accepted Answer · 2012-05-08T02:10:55

You want to change the pwm duty cycle between 0 to 1. Your existing code changes the pulse width in microseconds.

Arduino PWM to Android IOIO PWM

1 Answers