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Topic: Need help with programming a robotic arm with a minimum of 3 servos (Read 6463 times) previous topic - next topic

Drew Davis

I have the code mostly working. Could you send me a picture of how you built your robot. It depends how I finish up the code. 

Also I have added lots of comments so you can understand how it works. That way you can explain everything if your teacher asks!

Drew Davis

Some times I can't get pictures to load on the forum. If thats the case IM me and I will give you my email.


You don't normally need two servos for "up" and "down".   One servo will move the arm in both directions.

Drew Davis

Not if you want the up and down to have two points of motion. This Arm has six servos so I assume their is more then one servo controlling up and down.


Some servo test code for more than one servo.

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() {

  //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: ");
          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);
          Serial.print("writing Angle: ");
          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

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Not if you want the up and down to have two points of motion. This Arm has six servos so I assume their is more then one servo controlling up and down.

So if "up" and "down"  actually represent two completely different motions driven by two different servos,    then what do you call it when the "up" motion is reversed ?    -Up  ?

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