CODEWITHSUNDEEP
pythonraspberry-piarduino-unoraspberry-pi2
romy mathew
romy mathew

Reputation: 41

why simple led python program not working

I am testing my pi for the first time and i cant able to run the first program to light the led.

below is my code id from raspberry cookbook 

import Rpi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCD)
GPIO.setup(18,GPIO.OUT)
while(True):
GPIO.output(18, True)
time.sleep(1)
GPIO.output(18,False)
time.sleep(1)

when i run the script sudo python led.py it shows no error but the led has no output. I tried connecting a 360ohms between pin 18 and led. also tried connecting 540Ohms between pin 18 and led but no result.

Can anyone suggest how to debug the problem

Upvotes: 1

Views: 2507

Answers (3)

romy mathew
romy mathew

Reputation: 41

Thanks all for the comments and suggestion, when I added the GPIO.clearup() and restarted the system it starts blinking....

below is the comeple code i used...

import Rpi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCD)
GPIO.setup(18,GPIO.OUT)

while(True):

       GPIO.output(18, GPIO.HIGH)
       time.sleep(1)
       GPIO.output(18,False)
       time.sleep(1)

GPIO.CLEARUP()

THANKS EVERYONE FOR THE HELP....

Upvotes: 1

nagordon
nagordon

Reputation: 1367

This should blink the light on and off and worked for me

from time import sleep
import RPi.GPIO as gpio
gpio.setmode(gpio.BCM)
gpio.setup(18, gpio.OUT)
gpio.output(18, True)
sleep(5)
gpio.output(18, False)

Upvotes: 1

Foon
Foon

Reputation: 6458

You should probably (and I don't know if either main stack or the EE-centric or the RPi spinoffs has a good way to do this inline) include some sort of diagram showing which pins you're connecting. At a minimum, you need to do GPIO 18 to LED to GND, and as LED is Light Emitting Diode or something to that effect, you need to make sure your LED is pointing in the correct direction. I'd suggest as a way to debug this partially, take python out of the loop and just configure the LED to be always on by writing a 1 to the appropiate /sys/blah/path. Also, http://elinux.org/RPi_Low-level_peripherals#sysfs (which has the path you need) points out... GPIO 24 is wired to P1_18 so you might want to double check that the pin you think is 18 is called 18 on both sides of the system.

Upvotes: 1

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