从小对机器人非常感兴趣，正好身边有一个raspberry pi，平时就当Linux的服务器练练命令行，写写脚本。这次打算把raspberry pi的强大的GPIO都利用起来，做个小机器人。
首先从网上买了机器人相关的配件，主要是驱动机器人移动的电机、L298N电机驱动板、HC-SR04超声波距离探测传感器、机器人车身等配件。用来制作机器人的是raspberry pi B+。此型号一共有40个GPIO口，足以满足入门型机器人的制作要求。
以下是我连接L298N电机驱动板和HC-SR04距离传感器的GPIO针脚示意图。
3V3 |
5V |
uVcc |
|
SDA1 |
5V |
||
SCL1 |
GND |
||
GP4 |
TXD0 |
||
GND |
RXD0 |
||
N3 |
GP17 |
GP18 |
uEcho |
N2 |
GP27 |
GND |
uGND |
N1 |
GP22 |
GP23 |
N4 |
3V3 |
GP24 |
uTrig |
|
MOSI |
GND |
||
MISO |
GP25 |
||
SCLK |
CE0 |
||
GND |
CE1 |
||
EED |
EEC |
||
GP5 |
GND |
||
GP6 |
GP12 |
||
GP13 |
GND |
||
GP19 |
GP16 |
||
GP26 |
GP20 |
ENB |
|
GND |
GP21 |
ENA |
raspberry pi驱动电机的主要原理是，通过在电机两极上施加电压使之转动，利用两个针脚之间的高低电平差决定转动方向。
首先为了驱动电机，写了一个关于motor的类文件。
pi@raspberrypi ~/robot/class $ cat motor.py #!/usr/bin/python import RPi.GPIO as GPIO from time import sleep import sys import os,tty,termios,time time_sleep = 1 class motor: RIGHT = 15 LEFT = 16 RIGHTB = 13 LEFTB = 11 RIGHTPWM = 40 LEFTPWM = 38 def __init__(self): GPIO.setmode(GPIO.BOARD) GPIO.setwarnings(False) GPIO.setup(self.RIGHTPWM, GPIO.OUT) self.rightpwm = GPIO.PWM(self.RIGHTPWM, 500) self.rightpwm.start(0) GPIO.setup(self.RIGHT, GPIO.OUT) GPIO.setup(self.RIGHTB, GPIO.OUT) GPIO.setup(self.LEFTPWM, GPIO.OUT) self.leftpwm = GPIO.PWM(self.LEFTPWM,500) self.leftpwm.start(0) GPIO.setup(self.LEFT, GPIO.OUT) GPIO.setup(self.LEFTB, GPIO.OUT) def motor(self,leftspeed,left,rightspeed,right): # initiate speed self.rightpwm.ChangeDutyCycle(leftspeed*100) # leftspeed 0 to 1 GPIO.output(self.RIGHTPWM, right) # right True or False self.leftpwm.ChangeDutyCycle(rightspeed*100) # rightspeed 0 to 1 GPIO.output(self.LEFTPWM, left) # left True or False def forward(self,lspeed,rspeed, second): GPIO.output(self.LEFTB, False) GPIO.output(self.LEFT, True) GPIO.output(self.RIGHT, True) GPIO.output(self.RIGHTB, False) self.motor(lspeed,0,rspeed,0) if second > 0: time.sleep(second) self.stop() def stop(self): self.motor(0,0,0,0) def reverse(self, lspeed,rspeed, second): GPIO.output(self.LEFTB, True) GPIO.output(self.LEFT, False) GPIO.output(self.RIGHT, False) GPIO.output(self.RIGHTB, True) self.motor(lspeed,0,rspeed,0) if second > 0: time.sleep(second) self.stop() def right(self, lspeed, rspeed, second): GPIO.output(self.LEFTB, True) GPIO.output(self.LEFT, True) GPIO.output(self.RIGHT,True) GPIO.output(self.RIGHTB, False) self.motor(lspeed,0,rspeed,0) if second > 0: time.sleep(second) self.stop() def left(self, lspeed, rspeed, second): GPIO.output(self.LEFTB, False) GPIO.output(self.LEFT, True) GPIO.output(self.RIGHT,True) GPIO.output(self.RIGHTB, True) self.motor(lspeed,0,rspeed,0) if second > 0: time.sleep(second) self.stop() def pivot_right(self, lspeed, rspeed, second): GPIO.output(self.LEFTB, True) GPIO.output(self.LEFT, False) GPIO.output(self.RIGHT,True) GPIO.output(self.RIGHTB, False) self.motor(lspeed,0,rspeed,0) if second > 0: time.sleep(second) self.stop() def pivot_left(self, lspeed, rspeed, second): GPIO.output(self.LEFTB, False) GPIO.output(self.LEFT, True) GPIO.output(self.RIGHT,False) GPIO.output(self.RIGHTB, True) self.motor(lspeed,0,rspeed,0) if second > 0: time.sleep(second) self.stop()
然后编写通过控制端电脑键盘控制机器人的程序，此程序调用motor.py这个驱动脚本
#!/usr/bin/python
import motor
import time
import sys
import os,tty,termios,time
time_sleep = 0.070
lspeed = 1
rspeed = 1
m = motor.motor()
def getch():
fd = sys.stdin.fileno()
old_settings = termios.tcgetattr(fd)
try:
tty.setraw(sys.stdin.fileno())
ch = sys.stdin.read(1)
finally:
termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
return ch
while True:
char = getch()
if(char == 'w'):
m.forward(lspeed,rspeed,time_sleep)
if(char == 's'):
m.reverse(lspeed,rspeed,time_sleep)
if(char == 'a'):
m.left(lspeed,rspeed,time_sleep)
if(char == 'd'):
m.right(lspeed,rspeed,time_sleep)
if(char == 'q'):
m.pivot_left(lspeed,rspeed,time_sleep)
if(char == 'e'):
m.pivot_right(lspeed,rspeed,time_sleep)
if(char == 'c'):
os.system('/home/pi/camera/startstream.sh')
if(char == 'x'):
os.system('/home/pi/camera/stopstream.sh')
if(char == 'n'):
os.system('/home/pi/robot/class/autodrive.sh')
if(char == 'f'):
print("Program Ended")
break
此后我可以通过wifi网络用电脑远程控制机器人了。