Sample cheap peripherals from Ebay.

1. Sensors, actuators and the
Raspberry PI
Programming GPIO using Python

2. Raspberry PI vs Desktop PC
• Smaller footprint
• Slower processor

Less memory

Non-standard peripherals

6. Using GPIO – output mode
import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM) # refer to GPIO pins
GPIO.setwarnings(False) # ignore warnings
GPIO.setup(pin, GPIO.OUT) # make GPIO pin for output
GPIO.output(pin, GPIO.HIGH) # turn ON GPIO pin
GPIO.output(pin, GPIO.LOW) # turn OFF GPIO pin

7. Using GPIO – input mode
import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM) # refer to GPIO pins
GPIO.setwarnings(False) # ignore warnings
GPIO.setup(pin, GPIO.IN) # make GPIO pin for input
val = GPIO.input(pin) # read GPIO pin

11. Relay Connections
Relay board Raspberry PI
GND 6
IN1 15 (GPIO 22)
IN2 16 (GPIO 23)
IN3 18 (GPIO 24)
IN4 22 (GPIO 25)
VCC 2

13. Relay controller sample code
import RPi.GPIO as GPIO
import time
pins = [22,23,24,25]
for p in pins:
GPIO.setup(p, GPIO.OUT)
while True:
for q in pins:
GPIO.output(q, GPIO.HIGH)
time.sleep(5)
for q in pins:
GPIO.output(q, GPIO.LOW)
time.sleep(5)

17. Sensor Connections
Sensor board Raspberry PI
GND 6
OUT 11 (GPIO 17)
VCC 2

18. Sensor sample code
pin = 17
GPIO.setup(pin, GPIO.IN) # make GPIO pin for input
state = GPIO.input(pin) # read GPIO pin
while True:
time.sleep(1)
r = GPIO.input(pin)
if (r != state):
state = r
print "state changed"

21. AD/DA board connections
AD/DA board Raspberry PI
SDA 3
SCL 5
VCC 2
GND 6

22. Convertor sample code
import smbus
def read(a):
bus.read_byte_data(0x48, a)
return bus.read_data(0x48)
bus = smbus.SMBus(1)
control = read(0)
light = read(1)
temperature = read(2)
custom = read(3)
bus.write_byte(self.addr, 99)