Electronics

Introducing Raspberry Pi’s electronic features.

GPIOs

The board.

_images/gpio-pins.jpg

Symbolically.

_images/basic-gpio-layout.png

Our project

_images/simple-circuit.png

A Breadboard

Columns and rows are linked.

_images/Breadboard_scheme.svg.png

Light up LED

Hook up the following:

  • wire: 1 Rpi (3.3v) <-> row 26
  • LED: row 26 + (longer leg) <-> row 25 - (shorter leg)
  • resistor: row 25 <-> - col
  • wire: - col <-> 6 Rpi (ground)

Blinking LED

Python to control BPIO

switch 1 Rpi (3.3v) to 7

Type:

pi@raspberrypi ~ $ sudo ipython
In [1]: import RPi.GPIO as GPIO
In [2]: GPIO.setmode(gpio.BOARD)
In [3]: GPIO.setup(7, gpio.OUT)
In [4]: GPIO.output(7, True)
In [5]: GPIO.output(7, False)

Note we have to be superuser to operate the GPIOs.

Type:

pi@raspberrypi ~ $ sudo ipython
In [1]: import RPi.GPIO as GPIO
In [2]: from time import sleep
In [3]: GPIO.setmode(GPIO.BOARD)
In [4]: GPIO.setup(7, GPIO.OUT)
In [5]: for _ in range(5):
   ....:     GPIO.output(7, True)
   ....:     sleep(1)
   ....:     GPIO.output(7, False)
   ....:     sleep(1)
   ....:

Exercise

Put the above into a script and run it.

Exercise

‘Blinking Big Ben’

Make a program to communicate the time via LED.

Decide which unit of time to measure. Maybe every 2 minutes.