First time actually using the hedears on my raspberry pi zero w. These headers were soldered on when I got it.

When I connect my red lead to the 5v pin, it lights up, so the circuit's correct. When I connect it to pin 16, I get nothing. I believe I'm interpreting the pins correctly.

It occurs to me the I think I assumed that the pins put out 5 V.

Here it is lit with 5v.

enter image description here

Here it is attached to pin 16:

enter image description here

Here is my source code:

#include <wiringPi.h>
const int RED_LED = 16;
int main (void)
    wiringPiSetup () ;
    pinMode (RED_LED, OUTPUT) ;
    for (;;)
        digitalWrite (RED_LED, HIGH);
        digitalWrite (RED_LED, LOW);
        delay(500) ;
    return 0 ;

1 Answer 1


The function wiringPiSetup() tells the wiringPi library to use its own numbering scheme.

wiringPi 16 refers to GPIO 15 which is connected to pin 10.

See https://pinout.xyz/

I strongly suggest you get jumper leads soon. Crocodile leads make it too easy to short adjacent pins.

ALL Pi GPIO are 3V3.

  • I tried physical pin 10, but that didn't get me any light either. Should I not be using wiringPiSetup()?
    – Thom
    May 12, 2021 at 20:21
  • You can use any function you want. It is personal preference.
    – joan
    May 12, 2021 at 20:26

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