Powering Motor with Raspberry pi and h-bridge

Question

I am trying to control a 3-6 volt motor with a raspberry pi and h-bridge. I have a separate power source for my pi and my motors.

I have tried a 6v, 9v, and 12v power source. However, the motor buzzes but will not turn. (The motors turn when power is directly applied).

I am using the code supplied in this link: https://projects.raspberrypi.org/en/projects/physical-computing/16

Is it possible the H-bridge is fried, or is the voltage drop that great? Any suggestion would be great. Also if there is a better way to directly control the motors I am all ears.

Answer 1

You are missing ground / common connection between Pi and the driver board

Answer 2

You must connect GND pin of your raspi to ground of bridge (- of battery) Then you can use these code for test :

import RPi.GPIO as gpio

gpio.setmode(gpio.BCM) #setpinout as BCM

#Motor1
gpio.setup(m1in1, gpio.OUT) #m1in1 = motor 1 input 1
gpio.setup(m1in2, gpio.OUT) #m2in2 = motor 1 input 2
gpio.output(m1in1,True) #Set first pin High
gpio.output(m1in2,False) # Set second pin LOW 
# This High Low Setting means dc motor will turn forward ( Low - High means backward)

# set enable pin as output pin
gpio.setup(m1en,gpio.OUT)
m1=gpio.PWM(m1en,1000) # 1000 Hz frequency
m1.start(0) 

Then you can use the command :

m1.ChangeDutyCycle(x) #where 0<x<100

That way you can learn how slow and faster your motor can turn. Some motors start turning when x = 25 , some are x = 50..

Here you can find a tutorial about PWM Raspberry Pi PWM Tutorial

*You must use enable pin for this tutorial