MG90D Servos with Arduino

[chebe]

Take one Arduino Uno, and run some servos. Seemed straight-forward. Seemed.

Firstly, I couldn't find any Unos or Duemilanoves, I must have used them all. Guess it's time to finally break out the Mega 2560.

The servos are the MG90D micro servos. And using the Servo.h library.

Basic circuit set up like the sweep tutorial; on a breadboard, using a 100 µF capacitor (servo is 4.8V to 6V DC voltage), and external 9V power supply. Sweep worked fine, but setting exact angles via write() would only sometimes work.

Servo Circuit
Made with Fritzing

After some poking around I learned that I needed to set the minimum and maximum pulse lengths for these particular servos. (The values from the product description on Adafruit. Also note, this servo will 'hold' the position even when no signal is sent.) And then I could set the degree of rotation (0°-180°) as expected.

#include <Servo.h>

Servo myServo;

int minPulseWidth = 750; // µs == 0.75ms
int maxPulseWidth = 2250; // µs == 2.25ms

void setup()
{
  myServo.attach(9, minPulseWidth, maxPulseWidth); // digital pin (with PWM) 9
}

void loop()
{
  myServo.write(90); // angle in degrees, 0-180
  delay(1000); // ms
  myServo.write(180); // angle in degrees, 0-180
  delay(1000); // ms
  myServo.write(0); // angle in degrees, 0-180
  delay(1000); // ms
}