文章目录
- 连接
- 代码
- 控制单个舵机的旋转
- pc8596.py
- servo.py
- main.py
- 利用两个舵机拓展板控制16个舵机
今天我们来学习下
OpenMV的舵机拓展板来控制多个舵机同时使用
如果我们想控制三个以上的舵机,就需要用到舵机拓展板PCA9685
PCA9685使用的是I2C协议
,我们可以直接使用PCA9685舵机拓展板来控制八个舵机
舵机的供电采用的是4.8V-6V的电源
,我们可以用四节~五节干电池来进行供电(一节干电池就是1.2V的电压) ——不能使用3.7V的锂离子电池供电!
对于电源的供电,我们直接将电源连接到OpenMV的VCC和GND两个引脚即可
连接
将电机拓展板PCA9685插到OpenMV上,电源(4.8V~6V)连接到右侧的VCC和GND上
一个有八个引脚,可以控制八个舵机,每排引脚从上往下是:PWM(信号线)、VCC(电源线)、GND(地线)
舵机的编号从左到右编号为0-7
代码
控制单个舵机的旋转
核心代码:servo.position(i, x) # 控制第i号舵机旋转x°
pc8596.py
import utime
import ustruct
class PCA9685:
def __init__(self, i2c, address=0x40):
self.i2c = i2c
self.address = address
self.reset()
def _write(self, address, value):
self.i2c.writeto_mem(self.address, address, bytearray([value]))
def _read(self, address):
return self.i2c.readfrom_mem(self.address, address, 1)[0]
def reset(self):
self._write(0x00, 0x00)
def freq(self, freq=None):
if freq is None:
return int(25000000.0 / 4096 / (self._read(0xfe) - 0.5))
prescale = int(25000000.0 / 4096.0 / freq + 0.5)
old_mode = self._read(0x00)
self._write(0x00, (old_mode & 0x7F) | 0x10)
self._write(0xfe, prescale)
self._write(0x00, old_mode)
utime.sleep_us(5)
self._write(0x00, old_mode | 0xa1)
def pwm(self, index, on=None, off=None):
if on is None or off is None:
data = self.i2c.readfrom_mem(self.address, 0x06 + 4 * index, 4)
return ustruct.unpack('<HH', data)
data = ustruct.pack('<HH', on, off)
self.i2c.writeto_mem(self.address, 0x06 + 4 * index, data)
def duty(self, index, value=None, invert=False):
if value is None:
pwm = self.pwm(index)
if pwm == (0, 4096):
value = 0
elif pwm == (4096, 0):
value = 4095
value = pwm[1]
if invert:
value = 4095 - value
return value
if not 0 <= value <= 4095:
raise ValueError("Out of range")
if invert:
value = 4095 - value
if value == 0:
self.pwm(index, 0, 4096)
elif value == 4095:
self.pwm(index, 4096, 0)
else:
self.pwm(index, 0, value)
servo.py
import pca9685
import math
class Servos:
def __init__(self, i2c, address=0x40, freq=50, min_us=600, max_us=2400, degrees=180):
self.period = 1000000 / freq
self.min_duty = self._us2duty(min_us)
self.max_duty = self._us2duty(max_us)
self.degrees = degrees
self.freq = freq
self.pca9685 = pca9685.PCA9685(i2c, address)
self.pca9685.freq(freq)
def _us2duty(self, value):
return int(4095 * value / self.period)
def position(self, index, degrees=None, radians=None, us=None, duty=None):
span = self.max_duty - self.min_duty
if degrees is not None:
duty = self.min_duty + span * degrees / self.degrees
elif radians is not None:
duty = self.min_duty + span * radians / math.radians(self.degrees)
elif us is not None:
duty = self._us2duty(us)
elif duty is not None:
pass
else:
return self.pca9685.duty(index)
duty = min(self.max_duty, max(self.min_duty, int(duty)))
self.pca9685.duty(index, duty)
def release(self, index):
self.pca9685.duty(index, 0)
main.py
import time
from servo import Servos
from machine import I2C, Pin
i2c = I2C(sda=Pin('P5'), scl=Pin('P4'))
servo = Servos(i2c, address=0x40, freq=50, min_us=500, max_us=2500, degrees=180)
while True:
for i in range(0, 8):
servo.position(i, 0)
time.sleep_ms(500)
for i in range(0, 8):
servo.position(i, 180)
time.sleep_ms(500)
利用两个舵机拓展板控制16个舵机
import time
from servo import Servos
from machine import I2C, Pin
i2c = I2C(sda=Pin('P5'), scl=Pin('P4'))
servo1 = Servos(i2c, address=0x40, freq=50, min_us=500, max_us=2500, degrees=180)
servo2 = Servos(i2c, address=0x60, freq=50, min_us=500, max_us=2500, degrees=180)
while True:
for i in range(0, 8):
servo1.position(i, 0)
time.sleep_ms(500)
for i in range(0, 8):
servo1.position(i, 180)
time.sleep_ms(500)
for i in range(0, 8):
servo2.position(i, 0)
time.sleep_ms(500)
for i in range(0, 8):
servo2.position(i, 180)
time.sleep_ms(500)
本文内容由网友自发贡献,版权归原作者所有,本站不承担相应法律责任。如您发现有涉嫌抄袭侵权的内容,请联系:hwhale#tublm.com(使用前将#替换为@)