Pibrella Fairground Ride. This lesson follows on from the Pelican Crossing lesson

Transcription

1 Pibrella Fairground Ride This lesson follows on from the Pelican Crossing lesson

2 Idle 3 Open an LX Terminal To use the Pibrella we will need superuser rights Type in sudo and press Enter This will open the IDLE 3 editor

3 Set up your Pibrella using the following GPIO pins import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BOARD) RED_LED = 13 YELLOW_LED = 11 GREEN_LED = 7 GPIO.setup (RED_LED, GPIO.OUT) GPIO.setup (YELLOW_LED, GPIO.OUT) GPIO.setup (GREEN_LED, GPIO.OUT)

4 Your first job is to get the lights working on a loop using The lights in the loop should go in the order 1. Red ON, Yellow OFF, Green OFF 2. Red ON, Yellow ON, Green OFF 3. Red ON, Yellow ON, Green ON import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BOARD) RED_LED = 13 YELLOW_LED = 11 GREEN_LED = 7 GPIO.setup (RED_LED, GPIO.OUT) GPIO.setup (YELLOW_LED, GPIO.OUT) GPIO.setup (GREEN_LED, GPIO.OUT)

5 It should look something like: import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BOARD) RED_LED = 13 YELLOW_LED = 11 GREEN_LED = 7 GPIO.setup (RED_LED, GPIO.OUT) GPIO.setup (YELLOW_LED, GPIO.OUT) GPIO.setup (GREEN_LED, GPIO.OUT)

6 Get the loop to run when the BUTTON on GPIO pin 23 is pressed. There are 3 lines of code and some indentation to add import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BOARD) RED_LED = 13 YELLOW_LED = 11 GREEN_LED = 7 GPIO.setup (RED_LED, GPIO.OUT) GPIO.setup (YELLOW_LED, GPIO.OUT) GPIO.setup (GREEN_LED, GPIO.OUT)

7 Did you get it correct? import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BOARD) RED_LED = 13 YELLOW_LED = 11 GREEN_LED = 7 BUTTON = 23 GPIO.setup (RED_LED, GPIO.OUT) GPIO.setup (YELLOW_LED, GPIO.OUT) GPIO.setup (GREEN_LED, GPIO.OUT) GPIO.setup (BUTTON, GPIO.OUT) if GPIO.input (BUTTON):

8 The button can be pressed or else it is not pressed. Add some code to get the lights to all go off if the button is not pressed if GPIO.input (BUTTON):

9 Did you get it correct? if GPIO.input (BUTTON): else: GPIO.output (RED, False) GPIO.output (YELLOW, False) GPIO.output (GREEN, False)

10 However, now if the button is not pressed it looks as if the ride is broken. Get it so that if the button is not pressed, all lights blink on and off at the same time if GPIO.input (BUTTON): else: GPIO.output (RED, False) GPIO.output (YELLOW, False) GPIO.output (GREEN, False)

11 Did you get it correct? if GPIO.input (BUTTON): else: GPIO.output (RED, False) GPIO.output (YELLOW, False) GPIO.output (GREEN, False) GPIO.output (RED, True) GPIO.output (YELLOW, True) GPIO.output (GREEN, True)

12 Now we have the However, when we press the button we do not want the ride to go on forever. We want the ride and the sequence of lights to repeat 5 times and then to go into the flashing light sequence to show that it is ready for the ride operator to press the button and start the ride again. We will need a new line for i in range(5): This means that the code uses the letter i to represent a number of repeat sequences The number in brackets represents the number of repeat sequences Remember the : at the end of a line for a condition See if you can decide where to add in this line You will also need extra indentation

13 Did you get it correct? if GPIO.input (BUTTON): for i in range (5) else: GPIO.output (RED, False) GPIO.output (YELLOW, False) GPIO.output (GREEN, False) GPIO.output (RED, True) GPIO.output (YELLOW, True) GPIO.output (GREEN, True)

14 Now we need a motor to drive the ride. Connect the two wires from the motor (either way around) to the output E

15 The motor should come on, and stay on, when the button is pressed and the ride loops 5 times The motor should not come on if the button is not pressed The motor E is on GPIO pin 15. Call it OUT_E Add in these four lines of code

16 Did you get it correct? import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BOARD) RED_LED = 13 YELLOW_LED = 11 GREEN_LED = 7 BUTTON = 23 OUT_E = 15 GPIO.setup (RED_LED, GPIO.OUT) GPIO.setup (YELLOW_LED, GPIO.OUT) GPIO.setup (GREEN_LED, GPIO.OUT) GPIO.setup (BUTTON, GPIO.IN) GPIO.setup (OUT_E, GPIO.OUT) if GPIO.input(BUTTON): GPIO.output (OUT_E, True) else: GPIO.output (OUT_E, False)

17 Now we need another red light at the entrance gate to warn people that the ride is in operations. This will be another output The motor is already using Output E so add an LED across the two connections of Output F Call this OUT_F. It will use GPIO pin 16 Unlike a motor, an LED must be connected the correct way around An LED has two legs, one is shorter than the other. The short leg is called the Ground leg. This needs to be on the right. If your light does not work when you write and run the code, try reversing the RED

18 Did you get it correct? import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BOARD) RED_LED = 13 YELLOW_LED = 11 GREEN_LED = 7 BUTTON = 23 OUT_E = 15 OUT_F = 16 GPIO.setup (RED_LED, GPIO.OUT) GPIO.setup (YELLOW_LED, GPIO.OUT) GPIO.setup (GREEN_LED, GPIO.OUT) GPIO.setup (BUTTON, GPIO.IN) GPIO.setup (OUT_E, GPIO.OUT) GPIO.setup (OUT_F, GPIO.IOUT) if GPIO.input(BUTTON): GPIO.output (OUT_E, True) GPIO.output (OUT_F, True) else: GPIO.output (OUT_E, False) GPIO.output (OUT_F, False)

19 We could improve safety by getting the buzzer to sound at the same time as the red warning light. This will help visually impaired people identify that the ride is running The buzzer will be called BUZZER and will use GPIO Pin 12 The buzzer needs to switch on and then off to make a noise Add in these lines of code (Unfortunately the buzzer is not great quality but you should hear it)

20 Did you get it correct? import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BOARD) RED_LED = 13 YELLOW_LED = 11 GREEN_LED = 7 BUTTON = 23 BUZZER = 12 OUT_E = 15 OUT_F = 16 GPIO.setup (RED_LED, GPIO.OUT) GPIO.setup (YELLOW_LED, GPIO.OUT) GPIO.setup (GREEN_LED, GPIO.OUT) GPIO.setup (BUTTON, GPIO.IN) GPIO.setup (OUT_E, GPIO.OUT) GPIO.setup (OUT_F, GPIO.IOUT) GPIO.setup (BUZZER, GPIO.IOUT) if GPIO.input(BUTTON): GPIO.output (OUT_E, True) GPIO.output (OUT_F, True) GPIO.output (BUZZER, True) GPIO.output (BUZZER, False) GPIO.output (BUZZER, True) GPIO.output (BUZZER, False) else: GPIO.output (OUT_E, False) GPIO.output (OUT_F, False)

21 We need to be able to stop the ride We will need another button A button has 4 connectors Join a wire to A and another to B You can use a breadboard or solder on the wires This will go into INPUT A (either way around will do) We will call this IN_A It will use GPIO pin 21 Add in the lines of code to set up IN_A

22 Did you get it correct? import RPi.GPIO as GPIO import time GPIO.setmode(GPIO.BOARD) RED_LED = 13 YELLOW_LED = 11 GREEN_LED = 7 BUTTON = 23 BUZZER = 12 OUT_E = 15 OUT_F = 16 IN_A = 21 GPIO.setup (RED_LED, GPIO.OUT) GPIO.setup (YELLOW_LED, GPIO.OUT) GPIO.setup (GREEN_LED, GPIO.OUT) GPIO.setup (BUTTON, GPIO.IN) GPIO.setup (OUT_E, GPIO.OUT) GPIO.setup (OUT_F, GPIO.OUT) GPIO.setup (BUZZER, GPIO.OUT) GPIO.setup (IN_A, GPIO.IN) if GPIO.input(BUTTON): GPIO.output (OUT_E, True) GPIO.output (OUT_F, True) GPIO.output (BUZZER, True) GPIO.output (BUZZER, False) GPIO.output (BUZZER, True) GPIO.output (BUZZER, False) else: GPIO.output (OUT_E, False) GPIO.output (OUT_F, False)

23 Add in the line import sys (this imports the system library which you will need to stop or quit the program and turn the ride off) Make it so that if you press the input button IN_A It runs a line of code sys.exit()

24 Did you get it correct? import RPi.GPIO as GPIO import time import sys GPIO.setmode(GPIO.BOARD) RED_LED = 13 YELLOW_LED = 11 GREEN_LED = 7 BUTTON = 23 BUZZER = 12 OUT_E = 15 OUT_F = 16 IN_A = 21 GPIO.setup (RED_LED, GPIO.OUT) GPIO.setup (YELLOW_LED, GPIO.OUT) GPIO.setup (GREEN_LED, GPIO.OUT) GPIO.setup (BUTTON, GPIO.IN) GPIO.setup (OUT_E, GPIO.OUT) GPIO.setup (OUT_F, GPIO.OUT) GPIO.setup (BUZZER, GPIO.OUT) GPIO.setup (IN_A, GPIO.IN) if GPIO.input(BUTTON): GPIO.output (OUT_E, True) GPIO.output (OUT_F, True) GPIO.output (BUZZER, True) GPIO.output (BUZZER, False) GPIO.output (BUZZER, True) GPIO.output (BUZZER, False) else: GPIO.output (OUT_E, False) GPIO.output (OUT_F, False) if GPIO.input (IN_A): sys.exit()

25 Pibrella Fairground Ride Test your ride to see if it works as expected and make any final improvements