28byj48 4988

28BYJ-48是一款小巧廉价的步进电机，可以通过将其改造成2相4线的方式，使用专用的步进电机控制模块(A4988、DRV8825...)或者控制器控制它，从而获得更好的性能。其中A4988是一种微步进驱动器，可以将步进电机的步进角度分成更小的角度，从而提高步进电机的精度和平滑度。以下是28BYJ-48使用A4988控制的示例代码：

import RPi.GPIO as GPIO
import time

# 定义引脚
IN1 = 11
IN2 = 12
IN3 = 13
IN4 = 15

# 设置GPIO口为BCM编码方式
GPIO.setmode(GPIO.BCM)

# 忽略警告信息
GPIO.setwarnings(False)

# 设置引脚为输出
GPIO.setup(IN1, GPIO.OUT, initial=GPIO.LOW)
GPIO.setup(IN2, GPIO.OUT, initial=GPIO.LOW)
GPIO.setup(IN3, GPIO.OUT, initial=GPIO.LOW)
GPIO.setup(IN4, GPIO.OUT, initial=GPIO.LOW)

# 步进电机控制函数
def setStep(w1, w2, w3, w4):
    GPIO.output(IN1, w1)
    GPIO.output(IN2, w2)
    GPIO.output(IN3, w3)
    GPIO.output(IN4, w4)

# 步进电机正转函数
def forward(delay, steps):
    for i in range(steps):
        setStep(1, 0, 0, 1)
        time.sleep(delay)
        setStep(0, 1, 0, 1)
        time.sleep(delay)
        setStep(0, 1, 1, 0)
        time.sleep(delay)
        setStep(1, 0, 1, 0)
        time.sleep(delay)

# 步进电机反转函数
def backward(delay, steps):
    for i in range(steps):
        setStep(1, 0, 1, 0)
        time.sleep(delay)
        setStep(0, 1, 1, 0)
        time.sleep(delay)
        setStep(0, 1, 0, 1)
        time.sleep(delay)
        setStep(1, 0, 0, 1)
        time.sleep(delay)

# 主函数
if __name__ == '__main__':
    try:
        while True:
            delay = 0.005
            steps = 100
            forward(delay, steps)
            backward(delay, steps)
    except KeyboardInterrupt:
        GPIO.cleanup()