Jerking of servos

Projects Programming
1

Hi there,

I have 4 servos which is connected to arduino digital pin 9-12.
I am using 5V 1A wall adaptor to power servos.
When i connect two servo i can't see any jerks but as soon as i insert the third servo, they all starts jerking.
the servos are not under any load. Any idea what is happening?

2

Any idea what is happening?

Yes, you're not showing us the whole picture.

3

Yes, you're not showing us the whole picture.

I want to control 4 servo with 8 push button, 2 for each to control direction of servos.
Here is the code which i tried.

#include <Servo.h>

Servo myservo1;
Servo myservo2;
Servo myservo3;
Servo myservo4;
int button7=0;
int button6=0;
int button4=0;
int button5=0;
int button2=0;
int button3=0;
int pos1=180;
int pos2=180;
int pos3=0;
int pos4 = 90;

void setup()
{
pinMode(2, INPUT);
pinMode(3, INPUT);
pinMode(4, INPUT);
pinMode(5, INPUT);
pinMode(7, INPUT);
pinMode(6, INPUT);
myservo1.attach(9);
myservo2.attach(10);
myservo3.attach(11);
myservo4.attach(12);
myservo4.write(pos4);
myservo3.write(pos3);
myservo2.write(pos2);
myservo1.write(pos1);
}

void loop()
{
button2=digitalRead(2);
button3=digitalRead(3);
button4=digitalRead(4);
button5=digitalRead(5);
button7=digitalRead(7);
button6=digitalRead(6);

  delay(15);
  
  
  if(button7==1 && button6==0)
  {
  pos1=constrain(pos1,0,180);
  myservo1.write(pos1);
  pos1++;
  }
  
  if(button7==0 && button6==1)
  {
  pos1=constrain(pos1,0,180);
  myservo1.write(pos1);
  pos1--;
  }
  
  if(button5==1 && button4==0)
  {
  pos2=constrain(pos2,0,180);
  myservo2.write(pos2);
  pos2++;
  }
  
  if(button5==0 && button4==1)
  {
  pos2=constrain(pos2,0,180);
  myservo2.write(pos2);
  pos2--;
  }
  
  if(button3==1 && button2==0)
  {
  pos3=constrain(pos3,0,180);
  myservo3.write(pos3);
  pos3++;
  }
  
  if(button3==0 && button2==1)
  {
  pos3=constrain(pos3,0,180);
  myservo3.write(pos3);
  pos3--;
  }
}

for testing purpose i only attach the servos to arduino board to see if they are holding their respective position as set in the code
(pos1,pos2,pos3,pos4). when i attached only two servos they holding their position fine but as soon as i connect more than 2 servos they starts jerking.
using 5V 1A wall adaptor to power servos & grounds are common.

4

What model of servo are they? How much power do they need? In the absence of other detail, I'll guess that your power supply is inadequate.

5

What model of servo are they? How much power do they need? In the absence of other detail, I'll guess that your power supply is inadequate.

Servo Specs:

Operating Voltage : 4.8-6.0V

PWM Input Range : Pulse Cycle 20±2ms, Positive Pulse 1~2ms

STD Direction : Counter Clockwise / Pulse Traveling 1500 to 1900µsec

Stall Torque : 6 kg-cm (82.6 oz/in) at 4.8V, 7.1 Kg-cm (97.3 oz/in) at 6V

Operating Speed : 0.18 sec/ 60° at 4.8V, 0.16 sec/ 60° at 6V at no load

Weight : 40g (1.41 oz)

Size : 41.320.338.748.510

Plug Available : FUT, JR

Special Feature : Heavy Duty Plastic Gears, Economy Servo

6

I'd go with inadequate power supply too.