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I'm completely new to hardware in general. I just got a raspberry pi and was messing around trying to get an LED to light up.

I have everything wired like the picture below. I am using a 330ohm resister, which I believe is bigger therefore ok then what is required.

enter image description here

also (sorry this is my first time using any program to draw a circuit)

enter image description here

The program runs successfully, but no light comes on. I know the LED is good as I've tested it on the arduino. Anybody care to explain my wiring fault?

root@raspberrypi:/home/pi# cat test.py
#!/usr/bin/python
import RPi.GPIO as GPIO

GPIO.setmode(GPIO.BOARD)
GPIO.setup(11, GPIO.OUT)

GPIO.output(11, True)

Changing to GPIO pin 0 results

Traceback (most recent call last):
  File "test.py", line 5, in <module>
    GPIO.setup(0, GPIO.OUT)
RPi.GPIO.InvalidChannelException: The channel sent is invalid on a Raspberry Pi
root@raspberrypi:/home/pi#
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  • \$\begingroup\$ Have you confirmed the GPIO is actually at 3.3V? (or whatever the Rpi uses) Also, a schematic would be better than the picture, it's difficult to see what's connected to what. \$\endgroup\$
    – Oli Glaser
    Aug 12, 2012 at 19:54
  • \$\begingroup\$ Are you sere you don't need to add a pull-up resistor? Try connecting the resistor to +5V and invert the diode. \$\endgroup\$ Aug 12, 2012 at 20:29
  • \$\begingroup\$ That looks okay (I'm assuming the anode of the LED actually connects to the GPIO in the bottom diagram) Did you test the pin is set to a high (e.g. 3.3V) level when you run your program? Is the LED the right way round? \$\endgroup\$
    – Oli Glaser
    Aug 12, 2012 at 20:29
  • \$\begingroup\$ What color is the LED? \$\endgroup\$ Aug 21, 2012 at 20:47

4 Answers 4

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Try reversing the led. The longer lead should be connected to the gpio pin and not ground. Also are you using the correct pin? Some are disabled

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If your Fritzing diagram is correct, you've connected your LED to the S_CLK pin of the SPI bus, which is also known as pin 11. Try using one of the general purpose pins (GPIO0-7) rather than the special-purpose pins.

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Try using the Pin 4 (the bottom row, 4th pin, it is marked as #4 in Fritzing). Then change your program to:

import RPi.GPIO as GPIO

GPIO.setmode(GPIO.BCM) # Note the GPIO.BCM here, and not GPIO.BOARD
GPIO.setup(4, GPIO.OUT)
GPIO.output(4, True)

And run your program with "sudo", like this: sudo python ./my_prog.py.

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You're using Broadcom GPIO numbering for the channel but specified GPIO.BOARD as the numbering mode. Either change the numbering mode to GPIO.BCM or use 23 as the channel number.

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