Mega 2560 re-setting with Servo attached

Other Hardware Motors, Mechanics, Power and CNC
1

Please excuse me if this subject has been aired before, I did find an answer in this forum but I only wish to clarify this in my own mind.
As you will have guessed I'm new here, so please excuse my ignorance.

I've attached a servo and a switch to the mega using the code below, I've also attached a 12 supply to the mega to reduce the load on the USB port, which I understand can't handle the current needeed to drive the servo. This seems to work but the mega keeps resetting randomly when I throw the switch. Do I need to supply independant power to the servo and simply join the grounds?

Thanks in advance for your patience.

// Switch
// by Caspajack
// part of this example code taken from sweeep

#include <Servo.h>

Servo myservo; // create servo object to control a servo

int pos = 0; // variable to store the servo position
int pos1 = 170;

void setup()
{
myservo.attach(9); // attaches the servo on pin 9 to the servo object
pinMode(4,INPUT); // attach the switch between pin 4 and ground
pinMode (9,OUTPUT);
digitalWrite(4,HIGH); // initialise resistor on pin 4
}

void loop()
{
if (digitalRead(4)==HIGH)
{myservo.write(pos); // If switch thrown move servo to 'pos'
delay(15);}
else
{myservo.write(pos1); // tell servo to go to position in variable 'pos1'
delay(15);} // waits 15ms for the servo to reach the position
}

2

Servos must be powered by a separate supply. You can't use the 5V output of the Arduino for this purpose, as it can't supply the necessary current. Be sure to connect the grounds of the two supplies.

3

Thanks very much for the confirmation, I have added a seperate power supply and the Mega behaves perfectly. But it's nice to know I was on the right track.
Incidentally is there a way to put a loop between the point where I throw the switch to slow the servo down a bit. Something like this?

if (digitalRead(4)==HIGH)
{myservo.write(pos); // If switch thrown move servo to 'pos'
if (pos < 170); (pos = pos +1); {myservo.write(pos);
delay(15);}

else

Which as you've probably guessed doesn't work.
Thanks.

4

You want the servo to move slower?
Need to command the position change as a number of small steps, with some delay between steps.