# Jaikrishna
# Initial Date: June 25, 2013
# Last Updated: June 25, 2013
# http://www.dexterindustries.com/
# This code is for testing the BrickPi with Lego Motors & Lego Ultrasonic Sensor
# Make the connections with Left Motor at Port A, Right Motor at Port D and Sensor at Port 4
# Setup battery power source for the RPi & BrickPi and boot.
# To control the program, connection must be made though SSH though PuTTY or similar software
# Open up PuTTY and enter UserName:pi Password:raspberry (Default values)
# Navigate to the directory containing this code and enter 'python Car.py'
# The user needs to enter one of the following keys:
# 8 - Forward
# 4 - Left
# 6 - Right
# 2 - Reverse
# 5 - Stop
# Also, The motors automatically stop when any nearby object is detected using the Ultrasonic Sensor
from BrickPi import * #import BrickPi.py file to use BrickPi operations
import threading
BrickPiSetup() # setup the serial port for communication
BrickPi.MotorEnable[PORT_A] = 1 #Enable the Motor A
BrickPi.MotorEnable[PORT_D] = 1 #Enable the Motor D
BrickPi.SensorType[PORT_4] = TYPE_SENSOR_ULTRASONIC_CONT #Setting the type of sensor at PORT4
BrickPiSetupSensors() #Send the properties of sensors to BrickPi
running = True
class myThread (threading.Thread): #This thread is used for keeping the motor running while the main thread waits for user input
def __init__(self, threadID, name, counter):
threading.Thread.__init__(self)
self.threadID = threadID
self.name = name
self.counter = counter
def run(self):
while running:
if BrickPi.Sensor[PORT_4] < 20 : #Lesser value means more close
print "Car Stopped due to very close object"
BrickPi.MotorSpeed[PORT_A] = 0 # Set Speed=0 which means stop
BrickPi.MotorSpeed[PORT_D] = 0
BrickPiUpdateValues() # Ask BrickPi to update values for sensors/motors
time.sleep(.2) # sleep for 200 ms
thread1 = myThread(1, "Thread-1", 1) #Setup and start the thread
thread1.setDaemon(True)
thread1.start()
while True:
try:
c = raw_input("Enter direction: ") if c == '8' :
print "Running Forward"
BrickPi.MotorSpeed[PORT_A] = -200 #Set the speed of MotorA (-255 to 255)
BrickPi.MotorSpeed[PORT_D] = -200 #Set the speed of MotorD (-255 to 255)
elif c == '2' :
print "Running Reverse"
BrickPi.MotorSpeed[PORT_A] = 200 #Set the speed of MotorA (-255 to 255)
BrickPi.MotorSpeed[PORT_D] = 200 #Set the speed of MotorD (-255 to 255)
elif c == '6' :
print "Turning Right"
BrickPi.MotorSpeed[PORT_A] = -200 #Set the speed of MotorA (-255 to 255)
BrickPi.MotorSpeed[PORT_D] = 0 #Set the speed of MotorD (-255 to 255)
elif c == '4' :
print "Turning Left"
BrickPi.MotorSpeed[PORT_A] = 0 #Set the speed of MotorA (-255 to 255)
BrickPi.MotorSpeed[PORT_D] = -200 #Set the speed of MotorD (-255 to 255)
elif c == '5' :
print "Stopped"
BrickPi.MotorSpeed[PORT_A] = 0 #Stop the motor
BrickPi.MotorSpeed[PORT_D] = 0
except KeyboardInterrupt: #Triggered by pressing Ctrl+C
running = False #Stop theread1
print "Bye"
break #Exit
