樹莓派PCA9685的舵機MG996R二度自由雲臺操控代碼，搭配mqtt進行遠程操控

# -*- coding:utf-8 -*-
import time
#引入pca9685的原始代碼
import machine
#這裏加入了燈光展示
from light import Light
#引入mqtt的paho
import paho.mqtt.client as mqtt

#本地ip
MQTTHOST = "127.0.0.1"
#mqtt的端口號
MQTTPORT = 1883
#初始化mqttClient
mqttClient = mqtt.Client()

#初始化pwm
pwm = machine.PCA9685(0x40, debug=False)
#設置pwm的頻率
pwm.setPWMFreq(50)

#設置初始上下位置爲中間，（500+2500）/2 = 1500
up = 1500
#設置初始左右位置爲中間
dw = 1500
#設置燈的接口位置
led = Light(17)

# 消息處理函數
def on_message_come(client, userdata, msg):
    topicmsg = str(msg.payload.decode("utf-8"))
    msgList = topicmsg.split(',', 1)
    #evalFunc的作用是將接受的命令字符串變成對應的方法進行執行
    evalFunc(msgList[0], msgList[1])

# 連接MQTT服務器
def on_mqtt_connect():
    mqttClient.connect(MQTTHOST, MQTTPORT, 60)    

# subscribe 消息訂閱
def on_subscribe(top):
    mqttClient.subscribe(top, 1)  # 主題爲"mqtt"
    mqttClient.on_message = on_message_come  # 消息到來處理函數
    mqttClient.loop_forever()

def evalFunc(func, n):
    #例如獲取到了mqtt消息，right,1 ，這個表示執行向右1個單位，一共10個單位 
    print(str(func) + '(' + str(n) + ')')
    #eval可以調用方法進行執行
    eval(str(func) + '(' + str(n) + ')')

#這個是恢復到初始位置
def reset(n):
    led.blink()
    global up
    global dw
    for i in range(1400,1500,1):
        pwm.setServoPulse(0,i)
        time.sleep(0.00025)
    for i in range(1400,1500,1):
        pwm.setServoPulse(1,i)
        time.sleep(0.00025)
    up = 1500
    dw = 1500

#這個是向前進的代碼
def front(n):
    n = int(n)
    #這裏我自定義n乘以5，是因爲我之前每次執行一個單位，我想一次性執行5個單位的向下
    n = n * 5
    #燈光閃爍
    led.blink()
    global up
    #這裏會判斷是否已經到了閾值範圍，如果到了則不執行下一步
    if up != 2500:
        #開啓循環進行，從up到up+100*n,每次走100 * n個距離，當然這裏你可以10 * n,這樣舵機移動的角度非常小非常小
        #我這裏500~2500一共是2000個，分20下100 * n,當n爲1時，則移動20下從最前邊到最後邊，角度大概是從0度到180度這樣，具體度數描述不太準確，請見諒
        #現在n = n * 5,意味着我只需要4下就從最前邊到最後面，具體根據你的度數範圍來，還有根據你移動的角度大小來決定舵機的速度
        for i in range(up,up+100*n,1*n):
            pwm.setServoPulse(0,i)
            time.sleep(0.00025)
        #每次執行完畢後，up都會變化
        up += 100*n
        #這裏防止up變大超過2500，則變爲2500
        if up > 2500:
            up = 2500

def back(n):
    n = int(n)
    n = n * 5
    led.blink()
    global up
    if up != 500:
        for i in range(up,up-100*n,-1*n):
            pwm.setServoPulse(0,i)
            time.sleep(0.00025)
        up -= 100*n
        if up < 500:
            up = 500

def left(n):
    n = int(n)
    n = n * 2
    led.blink()
    global dw
    if dw != 2500:
        for i in range(dw,dw+100*n,1*n):
            pwm.setServoPulse(1,i)
            time.sleep(0.00025)
        dw += 100*n
        if dw > 2500:
            dw = 2500

def right(n):
    n = int(n)
    n = n * 2
    led.blink()
    global dw
    if dw != 500:
        for i in range(dw,dw-100*n,-1*n):
            pwm.setServoPulse(1,i)
            time.sleep(0.00025)
        dw -= 100*n
        if dw < 500:
            dw = 500

if __name__ == '__main__':
    topic='mqtt'
    on_mqtt_connect()
    on_subscribe(topic)

下面是machine的代碼，也就是PCA9685的python3測試代碼

#!/usr/bin/python

import time
import math
import smbus

# ============================================================================
# Raspi PCA9685 16-Channel PWM Servo Driver
# ============================================================================

class PCA9685:

  # Registers/etc.
  __SUBADR1            = 0x02
  __SUBADR2            = 0x03
  __SUBADR3            = 0x04
  __MODE1              = 0x00
  __PRESCALE           = 0xFE
  __LED0_ON_L          = 0x06
  __LED0_ON_H          = 0x07
  __LED0_OFF_L         = 0x08
  __LED0_OFF_H         = 0x09
  __ALLLED_ON_L        = 0xFA
  __ALLLED_ON_H        = 0xFB
  __ALLLED_OFF_L       = 0xFC
  __ALLLED_OFF_H       = 0xFD

  def __init__(self, address=0x40, debug=False):
    self.bus = smbus.SMBus(1)
    self.address = address
    self.debug = debug
    if (self.debug):
      print("Reseting PCA9685")
    self.write(self.__MODE1, 0x00)
	
  def write(self, reg, value):
    "Writes an 8-bit value to the specified register/address"
    self.bus.write_byte_data(self.address, reg, value)
    if (self.debug):
      print("I2C: Write 0x%02X to register 0x%02X" % (value, reg))
	  
  def read(self, reg):
    "Read an unsigned byte from the I2C device"
    result = self.bus.read_byte_data(self.address, reg)
    if (self.debug):
      print("I2C: Device 0x%02X returned 0x%02X from reg 0x%02X" % (self.address, result & 0xFF, reg))
    return result
	
  def setPWMFreq(self, freq):
    "Sets the PWM frequency"
    prescaleval = 25000000.0    # 25MHz
    prescaleval /= 4096.0       # 12-bit
    prescaleval /= float(freq)
    prescaleval -= 1.0
    if (self.debug):
      print("Setting PWM frequency to %d Hz" % freq)
      print("Estimated pre-scale: %d" % prescaleval)
    prescale = math.floor(prescaleval + 0.5)
    if (self.debug):
      print("Final pre-scale: %d" % prescale)

    oldmode = self.read(self.__MODE1);
    newmode = (oldmode & 0x7F) | 0x10        # sleep
    self.write(self.__MODE1, newmode)        # go to sleep
    self.write(self.__PRESCALE, int(math.floor(prescale)))
    self.write(self.__MODE1, oldmode)
    time.sleep(0.005)
    self.write(self.__MODE1, oldmode | 0x80)

  def setPWM(self, channel, on, off):
    "Sets a single PWM channel"
    self.write(self.__LED0_ON_L+4*channel, on & 0xFF)
    self.write(self.__LED0_ON_H+4*channel, on >> 8)
    self.write(self.__LED0_OFF_L+4*channel, off & 0xFF)
    self.write(self.__LED0_OFF_H+4*channel, off >> 8)
    if (self.debug):
      print("channel: %d  LED_ON: %d LED_OFF: %d" % (channel,on,off))
	  
  def setServoPulse(self, channel, pulse):
    "Sets the Servo Pulse,The PWM frequency must be 50HZ"
    pulse = pulse*4096/20000        #PWM frequency is 50HZ,the period is 20000us
    self.setPWM(channel, 0, int(pulse))

if __name__=='__main__':
 
  pwm = PCA9685(0x40, debug=False)
  pwm.setPWMFreq(50)
  while True:
   # setServoPulse(2,2500)
    for i in range(500,2500,10):  
      pwm.setServoPulse(0,i)   
      time.sleep(0.02)     
    
    for i in range(2500,500,-10):
      pwm.setServoPulse(0,i) 
      time.sleep(0.02)  

Python2的代碼在此

#!/usr/bin/python

import time
import math
import smbus

# ============================================================================
# Raspi PCA9685 16-Channel PWM Servo Driver
# ============================================================================

class PCA9685:

  # Registers/etc.
  __SUBADR1            = 0x02
  __SUBADR2            = 0x03
  __SUBADR3            = 0x04
  __MODE1              = 0x00
  __PRESCALE           = 0xFE
  __LED0_ON_L          = 0x06
  __LED0_ON_H          = 0x07
  __LED0_OFF_L         = 0x08
  __LED0_OFF_H         = 0x09
  __ALLLED_ON_L        = 0xFA
  __ALLLED_ON_H        = 0xFB
  __ALLLED_OFF_L       = 0xFC
  __ALLLED_OFF_H       = 0xFD

  def __init__(self, address=0x40, debug=False):
    self.bus = smbus.SMBus(1)
    self.address = address
    self.debug = debug
    if (self.debug):
      print("Reseting PCA9685")
    self.write(self.__MODE1, 0x00)
	
  def write(self, reg, value):
    "Writes an 8-bit value to the specified register/address"
    self.bus.write_byte_data(self.address, reg, value)
    if (self.debug):
      print("I2C: Write 0x%02X to register 0x%02X" % (value, reg))
	  
  def read(self, reg):
    "Read an unsigned byte from the I2C device"
    result = self.bus.read_byte_data(self.address, reg)
    if (self.debug):
      print("I2C: Device 0x%02X returned 0x%02X from reg 0x%02X" % (self.address, result & 0xFF, reg))
    return result
	
  def setPWMFreq(self, freq):
    "Sets the PWM frequency"
    prescaleval = 25000000.0    # 25MHz
    prescaleval /= 4096.0       # 12-bit
    prescaleval /= float(freq)
    prescaleval -= 1.0
    if (self.debug):
      print("Setting PWM frequency to %d Hz" % freq)
      print("Estimated pre-scale: %d" % prescaleval)
    prescale = math.floor(prescaleval + 0.5)
    if (self.debug):
      print("Final pre-scale: %d" % prescale)

    oldmode = self.read(self.__MODE1);
    newmode = (oldmode & 0x7F) | 0x10        # sleep
    self.write(self.__MODE1, newmode)        # go to sleep
    self.write(self.__PRESCALE, int(math.floor(prescale)))
    self.write(self.__MODE1, oldmode)
    time.sleep(0.005)
    self.write(self.__MODE1, oldmode | 0x80)

  def setPWM(self, channel, on, off):
    "Sets a single PWM channel"
    self.write(self.__LED0_ON_L+4*channel, on & 0xFF)
    self.write(self.__LED0_ON_H+4*channel, on >> 8)
    self.write(self.__LED0_OFF_L+4*channel, off & 0xFF)
    self.write(self.__LED0_OFF_H+4*channel, off >> 8)
    if (self.debug):
      print("channel: %d  LED_ON: %d LED_OFF: %d" % (channel,on,off))
	  
  def setServoPulse(self, channel, pulse):
    "Sets the Servo Pulse,The PWM frequency must be 50HZ"
    pulse = pulse*4096/20000        #PWM frequency is 50HZ,the period is 20000us
    self.setPWM(channel, 0, int(pulse))

if __name__=='__main__':
 
  pwm = PCA9685(0x40, debug=False)
  pwm.setPWMFreq(50)
  while True:
   # setServoPulse(2,2500)
    for i in range(500,2500,10):  
      pwm.setServoPulse(0,i)   
      time.sleep(0.02)     
    
    for i in range(2500,500,-10):
      pwm.setServoPulse(0,i) 
      time.sleep(0.02)

具體的代碼在此，包括python2和python3還有C的代碼都在此，想多瞭解的可以下載一下，也可以不下載，代碼也貼出來了，點擊下載