In this video I'm watching then instructor talks about using "jumpers". He's got a motor controller shield and at first he says that "during the making of this video we only had 1 jumper, thus only Pin 4 is working", and that as a result he could only move a motor/wheel in 1 direction.

He proceeds to find another jumper, uses it to make Pin 5 work, and then he can reverse polarity and change the direction the the wheel spins.

At first I thought that he must mean header pins, but when he holds the tiny component up, it looks like it's something else:

enter image description here

I read about a "power jumper" on an Adafruit page, but it only applied to one version of the Arduino and sounded like it was to do with Power joining (using the same power source for the motor and controller), so I really don't know if that's the same thing.


It's one of these (or similar). It connects two adjacent male header pins.

enter image description here

  • Thanks +1, will mark this as the answer. How are they used? I mean why would I want to connect 2 header pins together? – Hack-R Jul 29 '17 at 22:52
  • 1
    They can be used to form a connection that a user can elect to connect or disconnect as required for an application, or they can be used to choose between multiple mutually exclusive connections, e.g. powering a shield with either 3.3V or 5V sourced from the Arduino. – Ignacio Vazquez-Abrams Jul 29 '17 at 22:54
  • I mean why would I want to connect 2 header pins together? - it's very commonly done. For example I have a "minimal" board where I sometimes want a power LED to come on, and sometimes not (for measuring low-power consumption). So, I solder on two header pins side by side to make a gap in the circuit to the LED. To make the LED work I just slide on one of the jumper devices that Ignacio showed, and it bridges the gap and completes the circuit. – Nick Gammon Aug 17 '17 at 7:14

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