樹莓派舵機Servo Moto控制(軟體PWM)

舵機控制訊號腳頻寬及時序維基百科上的資料

大多數伺服馬達以時鐘的12點為中心點是脈衝寬度1.5m,

1 ms 的脈衝寬度當作 -90 度，

2 ms 則為 +90 度

但要看實際舵機的擺動角度

樹莓派GPIO接腳

Black – comes to GND (pin 6) from the Pi
Red – comes to 3V3 (pin 1) from the Pi
Yellow/Orange – to a free GPIO pin (e.g., GPIO17, pin 11)

 為了安全性可在Data PIN串接1k電阻,防止樹莓派燒毀

  (因舵機的電壓為4~6V高於Raspberry pi3.3V)

python 控制程式如下:

import RPi.GPIO as GPIO
import time

servoPIN = 17
GPIO.setmode(GPIO.BCM)
GPIO.setup(servoPIN, GPIO.OUT)

p = GPIO.PWM(servoPIN, 50) # GPIO 17 for PWM with 50Hz
#給ChangeDutyCycle及start的函數的參數為工作週期(dc)範圍0.0 <= dc <= 100.0
p.start(0) # Initialization
try:
  while True:
    p.ChangeDutyCycle(2.5)
    time.sleep(0.5)
    p.ChangeDutyCycle(5)
    time.sleep(0.5)
    p.ChangeDutyCycle(7.5)
    time.sleep(0.5)
    p.ChangeDutyCycle(10)
    time.sleep(0.5)
    p.ChangeDutyCycle(12.5)
    time.sleep(0.5)
    p.ChangeDutyCycle(10)
    time.sleep(0.5)
    p.ChangeDutyCycle(7.5)
    time.sleep(0.5)
    p.ChangeDutyCycle(5)
    time.sleep(0.5)
    p.ChangeDutyCycle(2.5)
    time.sleep(0.5)
except KeyboardInterrupt:
    p.stop()
finally:
    GPIO.cleanup()

#如舵機有輕微抖動你可稍微觸發ChangeDutyCycle(0)

#MG996R servos to have minimum pulse width around 771 and maximum around 2193 

#when running off 5v .

#目前台灣查到MG996R舵機(180度)的操控頻率,脈寬信號 500-1500-2500，對應的角度是0度~+-90度

#另外公式思考? ( (MaxPW – MinPW) * (180 / MaxAngle) ) + MinPW