Weird LED and Servo Issue

Projects Programming
1

Hi,

I am having a weird issue.

I was trying to fade a LED in a bigger project, and every time I tried fading the LED it would turn green, and then keep being green until the green channel on the led was set to zero.

I used hours trying to debug my code, and I would not figure out what was wrong. I then tried a simpler code that only controlled the RGB LED, and that worked, so eventually I figured out that if I attack my servo this issued occurs. I this a bug in the development tool or what is going on?

I am using version 1.7.10 for Liux 64 bit downloaded from arduino.org.

This is my test code.

#include <Servo.h>

// Pin Definitions
const int servoPin = 3;
const int blueLedPin = 9;
const int redLedPin = 10;
const int greenLedPin = 11;

// Servo Definition
Servo servoMotor;

void setup() {
  pinMode(greenLedPin, OUTPUT);
  pinMode(redLedPin, OUTPUT);
  pinMode(blueLedPin, OUTPUT);
  //servoMotor.attach(servoPin);
}

void loop() {
  for(int i=255; i > 0 ; i -= 1) {
    analogWrite(blueLedPin, i);
    analogWrite(greenLedPin, i);
    analogWrite(redLedPin, i);
    delay(7);
  }
  for(int i=0; i < 255 ; i += 1) {
    analogWrite(redLedPin, i); 
    delay(7);
  }
  delay(10000);
}

If you uncomment the servoMotor.attach line it will instead of fading out and then fading to red it will instantly turn Green, and the power off, and the fade to red.

2

Not weird at all, just the usual conflict over timer usage. Servo - Arduino Reference

3

Huh.. RT*M would have helped. :slight_smile: And it would also have been much faster then struggling with this issue.

Thank you for your reply. It was most helpful!

Since this is a UNO R3, can I them move the servo to Pin 9, and the LED to some other PWM enabled pins other than Pin 9 and 10, and everything should work?

Best Regards
Brian

4

You should be able to find some combination of pins that work. Study the library documentation for the limitations.