4

This is the problem: using this tutorial and Adafruit_Python_GPIO libs when start pwm and step up with DutyCycle and frequency I hear a weak sound from motor but unfortunely it doesn't move.

Wiring

enter image description here

Code

    import RPi.GPIO as GPIO
    from time import sleep

    ENABLE_PIN = 25
    IN1 = 24
    IN2 = 23
    ENGINE_FREQ = 500

    class pump:
        def __init__(self):
            self.enable_pin = ENABLE_PIN
            self.in1_pin = IN1
            self.in2_pin = IN2

            GPIO.setmode(GPIO.BCM)

            GPIO.setup(self.enable_pin, GPIO.OUT)
            GPIO.setup(self.in1_pin, GPIO.OUT)
            GPIO.setup(self.in2_pin, GPIO.OUT)

            self.pwm = GPIO.PWM(self.enable_pin, ENGINE_FREQ)

        def start(self):
            self.pwm.start(0)

            GPIO.output(self.in1_pin, True)
            GPIO.output(self.in2_pin, False)
            self.pwm.ChangeDutyCycle(100)

        def stop(self):
            self.pwm.stop()
            #GPIO.cleanup()

    if __name__ == '__main__':
        p = pump()
        p.start()
        sleep(5)
        p.stop()
        GPIO.cleanup()

What is wrong?

1 Answer 1

1

The code looks fine.

That suggests

  • loose wiring
  • weak batteries
  • stalled motor
7
  • putting batteries pack directly to motor, it work's fine.
    – pepperav
    Commented Oct 24, 2016 at 8:57
  • @pepperav It's a good idea to also edit such diagnostic information into your question so all relevant information is in one place. The schematic looks fine. Perhaps your wiring doesn't match the schematic. The L293D will drop a volt or so.
    – joan
    Commented Oct 24, 2016 at 9:33
  • I have set dtoverlay=pwm-2chan in /boot/config.txt
    – pepperav
    Commented Oct 24, 2016 at 9:47
  • @pepperav For any particular reason? I repeat edit new information into your question.
    – joan
    Commented Oct 24, 2016 at 10:15
  • because I thought that PWM was disabled. I'm using raspbian jessie lite.
    – pepperav
    Commented Oct 24, 2016 at 10:27

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