serial controlling a servo?

I got 2 servos in hopes of attaching them to my thermostats and having them turn the knobs but, i don't feel like changing the variables and re uploading the code to my arduino uno. How would I be able to send a serial signal my computer and set that to a var on the arduino witch will turn the servo?

failed try:

#include <Servo.h>

Servo servo;

int servoSerial;

void setup(){

Serial.begin(9600);

servo.attach(9);

}

void loop(){

servoSerial = Serial.read()

servo.writeMicroseconds (servoSerial);

}

Parents

0 gdstew over 12 years ago

Here is a two servo version of the previous program. I have also attempted to make it
more robust by:

1) Standardizing part of the error messages so they can be more easily recognized by
     the sending program.
2) Adding a short standard response message when the command is accepted and the
     function to change the servo position has been executed. Note that this does not verify
    that the servo position has changed, only that the function to change it has been
    executed.

I added many comments to make it easier to understand.

I also fixed an error in the program where in a couple of places the command input
buffer name was wrong (input instead of inputBuffer).

// Test program for the SG-90 servo motor
//
// to change servo 1 position send 1S0# - 1S180# command to Arduino
//   serial port
//
// to change servo 2 position send 2S0# - 2S180# command to Arduino
//   serial port

#include <Servo.h>

#define SerialSpeed 9600
#define BufferLength 16
#define LineEnd '#'

// Define Ardunio connector pin numbers used for servo motors, pins 9, 10,
// and 11 can also be used

#define PinServo1 5
#define PinServo2 6

// These can be changed to fit servo range needed

#define DefaultPosition 90
#define MinPosition 0
#define MaxPosition 180

// Create two servo objects using the servo library

Servo servo1 ;
Servo servo2 ;

char inputBuffer[BufferLength] ; // Buffer used for incomming servo position
                                 // commands

void setup()
{
   // Configure Arduino I/O pins

   pinMode(PinServo1, OUTPUT) ;
   pinMode(PinServo2, OUTPUT) ;

   // Attach servos per servo library and move to default position

   servo1.attach(PinServo1) ;
   servo1.write(DefaultPosition) ;
   servo2.attach(PinServo1) ;
   servo2.write(DefaultPosition) ;

   // Initialize serial port

   Serial.begin(SerialSpeed) ;
}

void HandleCommand(char *inputBuffer, int length)
{
    // Minimum command is 1S0# or 2S0#, 4 characters

    if (length < 4)
      {
       // Send error message to serial port

        Serial.println("ERROR: Invalid command length") ;
        return ; // Invalid command length
      }

    int value = 0 ;

    value = atoi(&inputBuffer[2]) ; // Convert ASCII position string to an integer

    // Check for minimum and maximun servo position settings

    if ((value < MinPosition) || (value > MaxPosition))
      {
       // Send error message to serial port

        Serial.println("ERROR: Invalid servo position") ;
        return ; // Invalid position parameter
      }

    int *command = (int *)inputBuffer ; // Get a pointer to the first two characters in command buffer

    // See if the pointer points to a valid command in the command buffer

    switch (*command)
      {
        case '1S':

          servo1.write(value) ; // Servo 1 position command found, change servo position
          Serial.println("OK") ; // Send command executed response
          break ;

        case '2S':

          servo2.write(value) ; // Servo 2 position command found, change servo position
          Serial.println("OK") ; // Send command executed response
          break ;

        default:

          Serial.println("ERROR: Unknown command") ;
          break ;
      }
}

void loop()
{
// Get a command string from the serial port

   int inputLength = 0 ;

// Read incomming command from serial input buffer one character at a time putting
// it in the command buffer while looking for command terminator and making sure
// it does not over run the buffer

   do {
        while (!Serial.available())
         {
           // Other functions can be called from inside this loop but care must be taken that
           // they do not take so long to execute that incoming commands are missed

           ; // For now do nothing while waiting for commands to be received
         }

        inputBuffer[inputLength] = Serial.read() ; // Read one character at a time
      } while ((inputBuffer[inputLength] != LineEnd) && (++inputLength < BufferLength)) ;

    inputBuffer[inputLength] = 0 ; // Terminate command string with null
    HandleCommand(inputBuffer, inputLength) ; //
}
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0 gdstew over 12 years ago

Here is a two servo version of the previous program. I have also attempted to make it
more robust by:

1) Standardizing part of the error messages so they can be more easily recognized by
     the sending program.
2) Adding a short standard response message when the command is accepted and the
     function to change the servo position has been executed. Note that this does not verify
    that the servo position has changed, only that the function to change it has been
    executed.

I added many comments to make it easier to understand.

I also fixed an error in the program where in a couple of places the command input
buffer name was wrong (input instead of inputBuffer).

// Test program for the SG-90 servo motor
//
// to change servo 1 position send 1S0# - 1S180# command to Arduino
//   serial port
//
// to change servo 2 position send 2S0# - 2S180# command to Arduino
//   serial port

#include <Servo.h>

#define SerialSpeed 9600
#define BufferLength 16
#define LineEnd '#'

// Define Ardunio connector pin numbers used for servo motors, pins 9, 10,
// and 11 can also be used

#define PinServo1 5
#define PinServo2 6

// These can be changed to fit servo range needed

#define DefaultPosition 90
#define MinPosition 0
#define MaxPosition 180

// Create two servo objects using the servo library

Servo servo1 ;
Servo servo2 ;

char inputBuffer[BufferLength] ; // Buffer used for incomming servo position
                                 // commands

void setup()
{
   // Configure Arduino I/O pins

   pinMode(PinServo1, OUTPUT) ;
   pinMode(PinServo2, OUTPUT) ;

   // Attach servos per servo library and move to default position

   servo1.attach(PinServo1) ;
   servo1.write(DefaultPosition) ;
   servo2.attach(PinServo1) ;
   servo2.write(DefaultPosition) ;

   // Initialize serial port

   Serial.begin(SerialSpeed) ;
}

void HandleCommand(char *inputBuffer, int length)
{
    // Minimum command is 1S0# or 2S0#, 4 characters

    if (length < 4)
      {
       // Send error message to serial port

        Serial.println("ERROR: Invalid command length") ;
        return ; // Invalid command length
      }

    int value = 0 ;

    value = atoi(&inputBuffer[2]) ; // Convert ASCII position string to an integer

    // Check for minimum and maximun servo position settings

    if ((value < MinPosition) || (value > MaxPosition))
      {
       // Send error message to serial port

        Serial.println("ERROR: Invalid servo position") ;
        return ; // Invalid position parameter
      }

    int *command = (int *)inputBuffer ; // Get a pointer to the first two characters in command buffer

    // See if the pointer points to a valid command in the command buffer

    switch (*command)
      {
        case '1S':

          servo1.write(value) ; // Servo 1 position command found, change servo position
          Serial.println("OK") ; // Send command executed response
          break ;

        case '2S':

          servo2.write(value) ; // Servo 2 position command found, change servo position
          Serial.println("OK") ; // Send command executed response
          break ;

        default:

          Serial.println("ERROR: Unknown command") ;
          break ;
      }
}

void loop()
{
// Get a command string from the serial port

   int inputLength = 0 ;

// Read incomming command from serial input buffer one character at a time putting
// it in the command buffer while looking for command terminator and making sure
// it does not over run the buffer

   do {
        while (!Serial.available())
         {
           // Other functions can be called from inside this loop but care must be taken that
           // they do not take so long to execute that incoming commands are missed

           ; // For now do nothing while waiting for commands to be received
         }

        inputBuffer[inputLength] = Serial.read() ; // Read one character at a time
      } while ((inputBuffer[inputLength] != LineEnd) && (++inputLength < BufferLength)) ;

    inputBuffer[inputLength] = 0 ; // Terminate command string with null
    HandleCommand(inputBuffer, inputLength) ; //
}
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