DC motor controlled by Transistor connected to a GPIO pin and feed a PWM
signal for speed control. No direction.
Used for fans and applications where direction not needed.
This video explains setup and theory well.
This library was tested on a number of motors including the RF-310T-11400
The file rpi_dc_lib.py contains code for this component It consists of a class called TranDc and two methods
Class init:
| ID | Name | Type | Default | Help |
|---|---|---|---|---|
| (1) | pin | int | GPIO pin connected base of transistor | |
| (2) | freq | int | 50 | PWM freq in Hz of control signal |
| (3) | verbose | bool | False | Write pin actions to console |
The two methods are called
- dc_motor_run = Drive motor forward, two args = duty cycle % , step delay in seconds
- dc_clean_up = switchs GPIO pins off
More example code is in the Transistor_DC test.py file in test subfolder of rpiMotorLib repository.
This code will run motor up to max duty cycle % hold it for 5 seconds and then run it down to zero and then cleanup.
import time
import RPi.GPIO as GPIO
# import library
from RpiMotorLib import rpi_dc_lib
step_delay = .05
# intialise class object
MotorOne = rpi_dc_lib.TranDc(TranDc(26 ,200 ,True)
input("Press key to accelerate to 100")
for speed in range(0,100):
MotorOne.dc_motor_run(speed, step_delay)
time.sleep(5)
input("Press key to decelerate to 0")
for speed in range(100,0,-1):
MotorOne.dc_motor_run(speed, step_delay)
MotorOne.dc_clean_up()
GPIO.cleanup()
exit()