I bought a Ping Ultrasonic Range Finder. It has four pins that you connect to the Arduino. I see in Internet that they have three pins. What does represent each pin and where to connect it to? I have an Arduino Uno Starter Kit.

  • 1
    The sticks (they are really called pins) have these little white marks next to them. They're called letters. You read them and they tell you what the pins do.
    – Majenko
    Oct 15, 2015 at 19:01
  • @Majenko It's so thin I don't think I will read something there. Oct 15, 2015 at 19:05
  • 1
    I said next to not on.
    – Majenko
    Oct 15, 2015 at 19:08
  • @Majenko Right, you're right. What does it mean "echo", "vcc" and "Trig"? Oct 15, 2015 at 19:15

1 Answer 1


You have 4 pins.

  • Vcc: +5V supply voltage (it stands for Collector Voltage)
  • GND: Ground.
  • Trig: Causes an ultrasound pulse to be generated (it stands for Trigger)
  • Echo: Tells you when an echo has been received.

You can see how to wire and use it here: http://www.instructables.com/id/Easy-ultrasonic-4-pin-sensor-monitoring-hc-sr04/

  • In what do I use the trigger pin? Oct 16, 2015 at 13:32
  • @PichiWuana That link tells you.
    – Majenko
    Oct 16, 2015 at 14:00

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