Control a Raspberry Pi GPIO with Python

28 March 2021

Updated: 03 September 2023

Circuit Diagram

This script will make use of the GPIO Pins to flicker an LED

The circuit diagram is below:

Circuit diagram

I’ve used a $330\Omega$ resistor for the resistor connected in series $R_LED$ , however the resistance for a given LED can be calculated with this equation (From Circuit Specialists):

R_{LED} = \frac{V_{source} - V_{LED}}{I_{LED}}

It’s important to connect the LED in the correct direction on the circuit

Code

Below is a simple python script which will handle turning the GPIO pins on and off using the RPi.GPIO library

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import RPi.GPIO as GPIO
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import time
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pin = 21
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dur = 1
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GPIO.setmode(GPIO.BCM)
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GPIO.setwarnings(False)
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GPIO.setup(pin, GPIO.OUT)
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while True:
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  GPIO.output(pin, GPIO.HIGH)
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  print "LED ON"
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  time.sleep(dur)
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  GPIO.output(pin, GPIO.LOW)
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  print "LED OFF"
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  time.sleep(dur)