using Servo

Hardware Arduino Yún
1

Hey everyone,

Next step in my project is to use a servo. Right now my servo is connected and I'm using the Servo.h to send commands to it. If I go with servo1.write(0) and servo1.write(90) it works, but when I try servo1.write(180) it doesn't move. Why is that ?

Here my code:

#include <Adafruit_MotorShield.h>
#include "utility/Adafruit_PWMServoDriver.h"
#include <Bridge.h>
#include <Console.h>
#include <Wire.h>
#include <Servo.h>
#include <YunServer.h>
#include <YunClient.h>

Adafruit_MotorShield AFMS = Adafruit_MotorShield();
// Select which 'port' M1, M2, M3 or M4. In this case, M1
Adafruit_DCMotor *frontWheels = AFMS.getMotor(2);
// You can also make another motor on port M2
Adafruit_DCMotor *rearWheels = AFMS.getMotor(1);
// Declaring the servo that controls the webcam
Servo *servo1;

// The pin that the LED is attached to
const int ledPin = 13;

// We open the socket 5678 to communicate.
YunServer server(5678);

void setup() {
  Serial.begin(9600);

  // Attach the LED to pin 13 as output
  pinMode(ledPin, OUTPUT);
  digitalWrite(ledPin, HIGH);
  
  // Bridge startup
  Bridge.begin();

  // Create with the default frequency 1.6KHz
  AFMS.begin();

  // Front Wheels initialization
  frontWheels->setSpeed(150);
  frontWheels->run(FORWARD);
  frontWheels->run(RELEASE);

  // Rear Wheels initialization
  rearWheels->setSpeed(150);
  rearWheels->run(FORWARD);
  rearWheels->run(RELEASE);
  
  // Attach my servo to pin 10
  servo1->attach(10);

  server.noListenOnLocalhost();
  server.begin();
}

void loop() {
  int _speed;
  YunClient client = server.accept();

  // There is a new client
  if (client) {
    client.setTimeout(5);

    String command = "none";
    digitalWrite(ledPin, LOW);
    
    servo1->write(180);

    while (!command.equals("stop")) {
      if (client.available() > 0) {
        command = client.readString();

        Serial.println(command);

        if (command.length() == 3) {
          if (command.substring(1,3).toInt() > 0 && command.substring(1,3).toInt() <= 100) {
            _speed = map(command.substring(1,3).toInt(), 0, 100, 0, 255);
          } 
          _speed = map(command.substring(1,3).toInt(), 0, -100, 0, 255);
        }
        else if (command.length() == 4) {
          _speed = map(command.substring(1,4).toInt(), 0, 100, 0, 255);
        }
        else {
          _speed = 50;
        }

        if (command.substring(0,1).equals("f") && _speed > 0) {
          rearWheels->run(RELEASE);
          rearWheels->setSpeed(_speed);
          rearWheels->run(FORWARD);
        } 
        else if (command.substring(0,1).equals("b") && _speed > 0) {
          rearWheels->run(RELEASE);
          rearWheels->setSpeed(_speed);
          rearWheels->run(BACKWARD);  
        }
        else if (command.substring(0,1).equals("l") && _speed > 0) {
          frontWheels->run(RELEASE);
          frontWheels->setSpeed(165);
          frontWheels->run(BACKWARD);
        }
        else if (command.substring(0,1).equals("r") && _speed > 0) {
          frontWheels->run(RELEASE);
          frontWheels->setSpeed(165);
          frontWheels->run(FORWARD);
        }
        else if (command.substring(0,1).equals("s")) {
          frontWheels->run(RELEASE);
          rearWheels->run(RELEASE);
        }
        else if (command.substring(0,1).equals("0")) {
          Serial.println("SERRRVOOOO");
          for (int i = 0; i < 255; i++) {
            servo1->write(map(i, 0, 255, 0, 180));
            delay(3);
            }
        }
        else if (command.substring(0,2).equals("90")) {
          servo1->write(90);
        }
        else if (command.substring(0,3).equals("180")) {
          servo1->write(180);
        }
        delay(500);
      }
    }
    digitalWrite(ledPin, HIGH);
    client.stop();
  }
}

I confirmed that it does go in the else if (180)

Another thing is that I tried using the SoftwareServo librairy but it just doesn't compile on the Yun is there any reason why?

Thank you all

2

Hi

some servos can't reach 180 degrees... or better some servos doesn't work in the "default" pulse range (1-2ms) Arduino library generates. Try a lower value or use the "raw" writeMicroseconds() method to move your servo.

3

Thank you for your answer, I'll give writeMicroseconds a try, but what is weird is that if I execute the motorparty example the servo goes all the way to 180.

4

Yeah writeMicroseconds seem to fix my problem. Thank you luca for your input.