assign double to servo motor?

Other Hardware Motors, Mechanics, Power and CNC
1

Hi!
I am trying to increase the speed of my car little by little and was wondering if it is possible to assign a variable of type double to the servo motor? My servo takes values from 77 to 180. 78 is too fast for now and doesn't allow me to test the right thing so I would like to go in between 77 and 78 for example. Is it possible to use the write() command with 77.5 for example? Or will it destroy the servo by giving a high current input?
Thanks

2

Try servo.writeMicroseconds(), where the values are nominally from 1000 = 0 degrees, 1500 = 90 and 2000 = 180.

edit.... presumably you have a continuous servo, where the position is the speed.

3

Servo test code that might be useful for a continous rotation servo.

// zoomkat 3-28-14 serial servo incremental test code
// using serial monitor type a character (s to increase or a 
// to decrease) and enter to change servo position 
// (two hands required, one for letter entry and one for enter key)
// use strings like 90x or 1500x for new servo position 
// for IDE 1.0.5 and later
// Powering a servo from the arduino usually *DOES NOT WORK*.

#include<Servo.h>
String readString;
Servo myservo;
int pos=1500; //~neutral value for continous rotation servo
//int pos=90;

void setup()
{
  myservo.attach(7, 400, 2600); //servo control pin, and range if desired
  Serial.begin(9600);
  Serial.println("serial servo incremental test code");
  Serial.println("type a character (s to increase or a to decrease)");
  Serial.println("and enter to change servo position");
  Serial.println("use strings like 90x or 1500x for new servo position");
  Serial.println();
}

void loop()
{
  while (Serial.available()) {
    char c = Serial.read();  //gets one byte from serial buffer
    readString += c; //makes the string readString
    delay(2);  //slow looping to allow buffer to fill with next character
  }
  if (readString.length() >0) {
    if(readString.indexOf('x') >0) { 
      pos = readString.toInt();
    }

    if(readString =="a"){
      (pos=pos-1); //use larger numbers for larger increments
      if(pos<0) (pos=0); //prevent negative number
    }
    if (readString =="s"){
      (pos=pos+1);
    }

    if(pos >= 400) //determine servo write method
    {
      Serial.println(pos);
      myservo.writeMicroseconds(pos);
    }
    else
    {   
      Serial.println(pos);
      myservo.write(pos); 
    }
  }
  readString=""; //empty for next input
}
4

Thank you to the both of you. I tried writeMicroseconds() assigning 1000 is fully counterclockwise, 2000 fully clockwise, and 1500 being the midpoint. When I give the following command throttle.writeMicroseconds(1500) the engine stops, and with my type of battery (3S-LiPo), 1562 is the minimum value to make the wheels rotate. I figured out this value by testing values from 1500 and up. This allows me to increase the speed progressively and will be very helpful for my application.

Best,

~ Martin