Difference between revisions of "BakeBit - Servo"

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==Introduction==
 
==Introduction==
 
[[File:BakeBit - Servo.jpg|thumb|Servo]]
 
[[File:BakeBit - Servo.jpg|thumb|Servo]]
*BakeBit - Servo是一个舵机模块,内部包含一个直流电机和齿轮传动反馈系统。用去机器人等机械结构的驱动和控制。
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* The BakeBit - Servo is a servo module which contains a DC motor and a transmission system.
*舵机的转动和转角都是跟随着信号脉冲的宽度变化而变化的,控制信号为频率50Hz的PWM信号,该控制信号高电平部分范围为0.5ms—2.5ms,对应的舵机旋转角度为0-180°。
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* Its input signal is PWM. The motor's steering angle changes according to PWM signals' changes. The input PWM's frequency is 50Hz and its width is 0.5ms—2.5ms. The motor's steering angle is 0 - 180°。
*给舵机一个PWM信号,舵机便会旋转到对应的角度。信号停止在一个脉冲宽度时舵机也就不转了,停在对应的角度上.
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* A PWM input steers the motor to an angle. When no input signals are applied the motor will stop.
  
 
==特性==
 
==特性==

Revision as of 10:32, 14 December 2016

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1 Introduction

Servo
  • The BakeBit - Servo is a servo module which contains a DC motor and a transmission system.
  • Its input signal is PWM. The motor's steering angle changes according to PWM signals' changes. The input PWM's frequency is 50Hz and its width is 0.5ms—2.5ms. The motor's steering angle is 0 - 180°。
  • A PWM input steers the motor to an angle. When no input signals are applied the motor will stop.

2 特性

  • 使用标准的2.0mm 4 Pin BakeBit接口

舵机规格尺寸如下:

BakeBit - Servo

  • 规格参数如下:

BakeBit - Servo detail

  • 引脚说明:
引脚 名称 描述
1 SIG 信号
2 NC
3 5V 电源5V
4 GND

3 示例程序:Servo and Rotary Angle Sensor

这个示例演示用BakeBit - Rotary Angle Sensor来控制舵机的转动, 随着你转动电位器,舵机将在0~180角范围里旋转。

3.1 硬件连接

简单的将 舵机 模块插入D5接口,将电位器模块插入A0接口,如下面这样:

Servo and Rotary Angle Sensor-1.jpg Servo and Rotary Angle Sensor-2.jpg

3.2 示例源代码

import time
import bakebit
import random
 
# Connect the servo to digital port D5
# SIG,NC,VCC,GND
servo = 5
 
# Connect the BakeBit Rotary Angle Sensor to analog port A0
# SIG,NC,VCC,GND
potentiometer = 0
 
# Reference voltage of ADC is 5v
adc_ref = 5
 
# Vcc of the bakebit interface is normally 5v
bakebit_vcc = 5
 
# Full value of the rotary angle is 180 degrees, as per it's specs (0 to 180)
full_angle = 180
old_degrees = -1
 
bakebit.pinMode(potentiometer,"INPUT")
bakebit.bakeBitServo_Attach(servo)
 
 
while True:
    try:
        # Read sensor value from potentiometer
        sensor_value = bakebit.analogRead(potentiometer)
 
        # Calculate voltage
        voltage = round((float)(sensor_value) * adc_ref / 1023, 2)
 
        # Calculate rotation in degrees (0 to 180)
        degrees = int((voltage * full_angle) / bakebit_vcc)
 
        if degrees != old_degrees:
            print("sensor_value = %d voltage = %.2f degrees = %d" % (sensor_value, voltage, degrees))
            bakebit.bakeBitServo_Write(servo, degrees)
 
        old_degrees = degrees
 
    except KeyboardInterrupt:
        bakebit.bakeBitServo_Detach(servo)
        break
    except IOError:
        print ("Error")

Github


3.3 运行示例

假设你已经参考bakebit教程安装了BakeBit源代码,
要运行示例程序,可以在开发板上进入 BakeBit/Software/Python目录,运行bakebit_prj_Servo_And_RotaryAngleSensor.py:

cd ~/BakeBit/Software/Python
sudo python bakebit_prj_Servo_And_RotaryAngleSensor.py

3.4 运行结果

随着你转动电位器,舵机将在0~180角范围里旋转。

4 相关资料