BakeBit - Rotary Angle Sensor/zh

English

1 介绍

Rotary Angle Senso

• BakeBit - Rotary Angle Senso是一个旋转角度传感器模块，模块使用了一个旋转电位器。通过改变接入电路部分电阻线的长度来改变接入部分的电阻值，从而改变输出端的分压。

2 特性

• 使用标准的2.0mm 4 Pin BakeBit接口

• 引脚说明:

名称	描述
GND	地
5V	电源5V
NC	空
SIG	信号

3 示例程序(1)：LED Fade

这个项目将使用BakeBit - Rotary Angle Sensor模块，来动态调节LED的亮度。

3.1 硬件连接

简单的将 LED 模块插入 D5接口，将 BakeBit - Rotary Angle Sensor 插入 A0接口，如下面这样：

3.2 示例源代码

import time
import bakebit
 
# Connect the BakeBit Rotary Angle Sensor to analog port A0
# SIG,NC,VCC,GND
potentiometer = 0
 
# Connect the LED to digital port D5
# SIG,NC,VCC,GND
led = 5
 
bakebit.pinMode(potentiometer,"INPUT")
bakebit.pinMode(led,"OUTPUT")
time.sleep(1)
 
# 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 300 degrees, as per it's specs (0 to 300)
full_angle = 300
 
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 300)
        degrees = round((voltage * full_angle) / bakebit_vcc, 2)
 
        # Calculate LED brightess (0 to 255) from degrees (0 to 300)
        brightness = int(degrees / full_angle * 255)
 
        # Give PWM output to LED
        bakebit.analogWrite(led,brightness)
 
        print("sensor_value = %d voltage = %.2f degrees = %.1f brightness = %d" %(sensor_value, voltage, degrees, brightness))
    except KeyboardInterrupt:
        bakebit.analogWrite(led,0)
        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_rotary_angle_sensor.py:

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

3.4 运行结果

旋转电位器，LED亮度会随着电位器的角度变化而变化。

4 示例程序(2)：Servo and Rotary Angle Sensor

这个示例演示用电位器(Rotary Angle Sensor)来控制舵机的转动。
该示例是配合BakeBit - Servo来实现的，可参考BakeBit - Servo页面。

5 示例程序(3)：LED Bar and Rotary Angle Sensor

这个示例实现类拟音量调节的效果，用到电位器模块和LED Bar。
该示例是配合BakeBit - LED Bar来实现的，可参考BakeBit - LED Bar页面。

6 相关资料

• [Schematic](BakeBit - Rotary Angle Sensor.pdf)
• [BakeBit Github项目](https://github.com/friendlyarm/BakeBit)
• [BakeBit Starter Kit手册](http://wiki.friendlyarm.com/bakebit/bakebit_starter_kit_manual_cn.pdf)