I'm newbie in electronics. I'm joining RPi's world through a starter learning kit but there's a wiring incongruity in DC Motor lesson:
In the 1st image there's only RPi's 3.3V power. In the 2nd image there's a breadboard power supply module. The lesson says that L9110 needs a +5V power supply.
When I run the code below, the LED lights and the buttons work, but the motor doesn't work
#!/usr/bin/env python
import RPi.GPIO as GPIO
import time
STATUS_LED = 10
BTN_RUN_STOP = 11
BTN_DIRECTION = 12
BTN_SPEED_INCREASE = 13
BTN_SPEED_DECREASE = 15
MotorPin_A = 16
MotorPin_B = 18
g_sta = 1
g_dir = 1
speed = 50
pwm_B = 0
def motorStop():
GPIO.output(MotorPin_A, GPIO.HIGH)
GPIO.output(MotorPin_B, GPIO.LOW)
def setup():
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)
GPIO.setup(STATUS_LED, GPIO.OUT) # pin mode --- output
GPIO.setup(BTN_RUN_STOP, GPIO.IN, pull_up_down=GPIO.PUD_UP) # set pin mode as input, and pull it to high level.
GPIO.setup(BTN_DIRECTION, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(BTN_SPEED_INCREASE, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(BTN_SPEED_DECREASE, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(MotorPin_A, GPIO.OUT)
GPIO.setup(MotorPin_B, GPIO.OUT)
motorStop()
global pwm_B
pwm_B = GPIO.PWM(MotorPin_B, 2000) # create pwm and set frequece to 2KHz
def motor(status, direction, speed):
global pwm_B
if status == 1: # run
GPIO.output(STATUS_LED, GPIO.LOW) # led on
if direction == 1:
GPIO.output(MotorPin_A, GPIO.HIGH)
pwm_B.start(100)
pwm_B.ChangeDutyCycle(100-speed)
else:
GPIO.output(MotorPin_A, GPIO.LOW)
pwm_B.start(0)
pwm_B.ChangeDutyCycle(speed)
else: # stop
GPIO.output(STATUS_LED, GPIO.HIGH) # led off
motorStop()
def btnScan():
global g_sta
global g_dir
global speed
if GPIO.input(BTN_RUN_STOP) == GPIO.LOW:
time.sleep(0.01)
if GPIO.input(BTN_RUN_STOP) == GPIO.LOW:
g_sta = not g_sta
print 'g_sta = %d', g_sta
while not GPIO.input(BTN_RUN_STOP):
pass
if GPIO.input(BTN_DIRECTION) == GPIO.LOW:
time.sleep(0.01)
if GPIO.input(BTN_DIRECTION) == GPIO.LOW:
g_dir = not g_dir
print 'g_dir = %d', g_dir
while not GPIO.input(BTN_DIRECTION):
pass
if GPIO.input(BTN_SPEED_INCREASE) == GPIO.LOW:
time.sleep(0.01)
if GPIO.input(BTN_SPEED_INCREASE) == GPIO.LOW:
speed += 1
if speed > 100:
speed = 100
print 'speed = %d', speed
while not GPIO.input(BTN_SPEED_INCREASE):
pass
if GPIO.input(BTN_SPEED_DECREASE) == GPIO.LOW:
time.sleep(0.01)
if GPIO.input(BTN_SPEED_DECREASE) == GPIO.LOW:
speed -= 1
if speed < 0:
speed = 0
print 'speed = %d', speed
while not GPIO.input(BTN_SPEED_DECREASE):
pass
def loop():
while True:
# print 'test....2...'
btnScan()
# print 'test....3...'
global g_sta
global g_dir
global speed
motor(g_sta, g_dir, speed)
def destroy():
motorStop()
GPIO.cleanup() # Release resource
if __name__ == '__main__': # Program start from here
setup()
try:
loop()
except KeyboardInterrupt:
destroy()
I don't have another power supply for the breadboard power supply module, it accepts a DC 6.5V-12V input voltage and outputs 700mA (Max) current.
Can I feed it with the laptop's USB? If I feed it with a 12V power supply, which maximum current must output? Can I use RPi's 2nd pin?
What can I do?
