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Topic: Using Multiple Servos with Arduino (Read 11072 times) previous topic - next topic

Sluice

So, I have 8 servos that I want to drive with my Arduino. I know I shouldn't connect all the servos to the GND and +5v of Arduino. Somebody told me that servos when working pull about 2 amps each Is this correct? How should I hook an external battery with Arduino to my servos? I am told that I can hook up DC jack into Arduino, an external batteries GND to Arduino's GND, and the external batteries + to +5v on Arduino. Is this correct? Please help me out here.

JimboZA

Yep that's right. Have a look at my pic below, and go and read DuaneB's work, starting here. He has some test results for current draw.
"Could you do the egg bacon spam and sausage without the spam then? "

No PMs for help please.
DO NOT power servos from Arduino 5V: give them their own power and connect the grounds.

zoomkat

Google forum search: Use Google Advanced Search and use Http://forum.arduino.cc/index in the "site or domain:" box.

Sluice

Thanks Zimbo for the tremendous help. I'm enjoying the website you linked to your post, it's very helpful. What I'm making is a 4 legged spider! (I really hope it works :)
Zoomkat, makes perfect sense. Thank you as well.

JimboZA

Quote
Thanks Zimbo


That's Jimbo  8), but you're welcome all the same.

Yep DuaneB seems to be the go-to-guy for servo know-how.

[zen]Is a 4-legged spider really a spider?[/zen]
"Could you do the egg bacon spam and sausage without the spam then? "

No PMs for help please.
DO NOT power servos from Arduino 5V: give them their own power and connect the grounds.

aziz_wicaksono

oh it's so help me actually. Now, I use 5 servos in my project. Can anybody help me for give a little sketch ?  I am so confuse to start it.  :smiley-roll-sweat:

zoomkat


oh it's so help me actually. Now, I use 5 servos in my project. Can anybody help me for give a little sketch ?  I am so confuse to start it.  :smiley-roll-sweat:


Several servo control code.

Code: [Select]

//zoomkat 11-22-12 simple delimited ',' string parse
//from serial port input (via serial monitor)
//and print result out serial port
//multi servos added

String readString;
#include <Servo.h>
Servo myservoa, myservob, myservoc, myservod;  // create servo object to control a servo

void setup() {
  Serial.begin(9600);

  //myservoa.writeMicroseconds(1500); //set initial servo position if desired

  myservoa.attach(6);  //the pin for the servoa control
  myservob.attach(7);  //the pin for the servob control
  myservoc.attach(8);  //the pin for the servoc control
  myservod.attach(9);  //the pin for the servod control
  Serial.println("multi-servo-delimit-test-dual-input-11-22-12"); // so I can keep track of what is loaded
}

void loop() {

  //expect single strings like 700a, or 1500c, or 2000d,
  //or like 30c, or 90a, or 180d,
  //or combined like 30c,180b,70a,120d,

  if (Serial.available())  {
    char c = Serial.read();  //gets one byte from serial buffer
    if (c == ',') {
      if (readString.length() >1) {
        Serial.println(readString); //prints string to serial port out

        int n = readString.toInt();  //convert readString into a number

        // auto select appropriate value, copied from someone elses code.
        if(n >= 500)
        {
          Serial.print("writing Microseconds: ");
          Serial.println(n);
          if(readString.indexOf('a') >0) myservoa.writeMicroseconds(n);
          if(readString.indexOf('b') >0) myservob.writeMicroseconds(n);
          if(readString.indexOf('c') >0) myservoc.writeMicroseconds(n);
          if(readString.indexOf('d') >0) myservod.writeMicroseconds(n);
        }
        else
        {   
          Serial.print("writing Angle: ");
          Serial.println(n);
          if(readString.indexOf('a') >0) myservoa.write(n);
          if(readString.indexOf('b') >0) myservob.write(n);
          if(readString.indexOf('c') >0) myservoc.write(n);
          if(readString.indexOf('d') >0) myservod.write(n);
        }
         readString=""; //clears variable for new input
      }
    } 
    else {     
      readString += c; //makes the string readString
    }
  }
}

Google forum search: Use Google Advanced Search and use Http://forum.arduino.cc/index in the "site or domain:" box.

#7
Jan 06, 2014, 09:33 am Last Edit: Jan 06, 2014, 09:45 am by jmichael26 Reason: 1
hi! how to program it if i'll be needing more than 2 servo motors? thanks

i'll be making snake robot and there is 14 servo motors included.


just like this http://www.youtube.com/watch?v=YKlCzcH8oWk&feature=c4-overview&list=UUWVNKVqwlDwOcAsUMM4TJnA

JimboZA


hi! how to program it if i'll be needing more than 2 servo motors? thanks


Zoomcat's code in reply #6 shows 4 servos already, on pins 6, 7, 8 and 9.
"Could you do the egg bacon spam and sausage without the spam then? "

No PMs for help please.
DO NOT power servos from Arduino 5V: give them their own power and connect the grounds.

ahh but what if i'll be using 14 servos ?

JimboZA

Well you'll need an Arduino with 14 spare digital pins. Uno has 20 pins if you count the analogs, but lose 2 for Tx Rx leaves you a theoretical 18. Mega has dozens more .

I'm not sure if there's an absolute maximum that the servo library can handle though, sorry.
"Could you do the egg bacon spam and sausage without the spam then? "

No PMs for help please.
DO NOT power servos from Arduino 5V: give them their own power and connect the grounds.

my friend told me that i need to use sevo drivers to accomodate those servos. but i'm just worried about its program . please help me


Well you'll need an Arduino with 14 spare digital pins. Uno has 20 pins if you count the analogs, but lose 2 for Tx Rx leaves you a theoretical 18. Mega has dozens more .

I'm not sure if there's an absolute maximum that the servo library can handle though, sorry.


but how is the program if i'll be using 14 servos? just copy paste your #6 program? thanks

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