Difference between revisions of "BakeBit - Light Sensor"

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[[BakeBit - Light Sensor/zh|查看中文]]
 
[[BakeBit - Light Sensor/zh|查看中文]]
 +
 +
==介绍==
 +
[[File:BakeBit - Light Sensor.jpg|thumb|Light Sensor]]
 +
*BakeBit - Light Sensor是一个光敏电阻模块，主要器件是一个光敏电阻。光敏电阻的制作材料具有在特定波长的光照射下，其阻值迅速减小的特性。
 +
*这是由于光照产生的载流子都参与导电，在外加电场的作用下作漂移运动，电子奔向电源的正极，空穴奔向电源的负极，从而使光敏电阻器的阻值迅速下降。在电源激励下，输出端分压减小。
 +
 +
==特性==
 +
* 使用标准的2.0mm 4 Pin BakeBit接口
 +
* PCB尺寸（mm）：20x24
 +
* 模拟信号输出
 +
[[File:BakeBit - Light Sensor_PCB.png | frameless|350px|BakeBit - Light Sensor]]
 +
 +
* 引脚说明:
 +
{| class="wikitable"
 +
|-
 +
|名称 || 描述
 +
|-
 +
|GND  || 地
 +
|-
 +
|5V    || 电源5V
 +
|-
 +
|NC    || 空
 +
|-
 +
|SIG  || 信号
 +
|}
 +
== 示例程序：Smart Lighting ==
 +
 +
利用亮度传感器，聪明地控制灯光(灯用LED Bar来模拟)，环境越暗就让灯越亮，环境亮度足够时，就将灯变暗或者熄灭。
 +
本示例需要配合[[BakeBit - LED Bar]]使用。
 +
 +
=== 硬件连接 ===
 +
简单的将[[BakeBit - LED Bar]]模块插入 D3 接口，将[[BakeBit - Light Sensor]]插入 A0 接口，如下面这样：
 +
 +
::{| class="wikitable"
 +
|-
 +
|[[File:Smart Lighting-1.jpg|frameless|300px]]    || [[File:Smart Lighting-2.jpg |frameless|300px]]
 +
|-
 +
|}
 +
 +
=== 示例源代码 ===
 +
 +
<syntaxhighlight lang="python">
 +
import time
 +
import bakebit
 +
 +
# Connect the BakeBit Light Sensor to analog port A0
 +
# SIG,NC,VCC,GND
 +
light_sensor = 0
 +
 +
# Connect the BakeBit LED Bar to digital port D3
 +
# DI,DCKI,VCC,GND
 +
ledbar = 3
 +
 +
 +
lowThreshold = 500
 +
highTreshold = 600
 +
 +
bakebit.pinMode(light_sensor,"INPUT")
 +
bakebit.pinMode(ledbar,"OUTPUT")
 +
time.sleep(.2)
 +
bakebit.bakeBitLedBar_Init(ledbar, 0, 5)
 +
time.sleep(.5)
 +
old_color = 0
 +
 +
while True:
 +
    try:
 +
        light_count = 0
 +
 +
        # Get sensor value
 +
        sensor_value = bakebit.analogRead(light_sensor)
 +
        if sensor_value > highTreshold:
 +
            f=(1023-highTreshold)/4
 +
            light_count =  (sensor_value-highTreshold)/f+1
 +
 +
            # turn on ledbar
 +
            color16bit = bakebit.Green
 +
            if light_count > 1:
 +
                color16bit = color16bit | (bakebit.Green << 3)
 +
            if light_count > 2:
 +
                color16bit = color16bit | (bakebit.Green << 6)
 +
            if light_count > 3:
 +
                color16bit = color16bit | (bakebit.Green << 9)
 +
            if light_count > 4:
 +
                color16bit = 0
 +
                color16bit = color16bit | bakebit.Blue
 +
                color16bit = color16bit | (bakebit.Blue << 3)
 +
                color16bit = color16bit | (bakebit.Blue << 6)
 +
                color16bit = color16bit | (bakebit.Blue << 9)
 +
                color16bit = color16bit | (bakebit.Blue << 12)
 +
 +
            if color16bit != old_color:
 +
                old_color = color16bit
 +
                lowBits = color16bit & 255
 +
                highBits = (color16bit & (255 << 8)) >> 8
 +
                bakebit.bakeBitLedBar_Show(ledbar, highBits, lowBits)
 +
 +
        elif sensor_value < lowThreshold:
 +
            # turn off ledbar
 +
            bakebit.bakeBitLedBar_Show(ledbar, 0, 0)
 +
 +
        print("sensor_value = %d light_count =%d" %(sensor_value,  light_count))
 +
        time.sleep(.5)
 +
 +
    except KeyboardInterrupt:
 +
        bakebit.bakeBitLedBar_Release(ledbar)
 +
        time.sleep(.2)
 +
        break
 +
    except IOError:
 +
        print ("Error")
 +
 +
</syntaxhighlight>
 +
[https://github.com/friendlyarm/BakeBit/blob/master/Software/Python/bakebit_prj_SmartLighting.py Github]
 +
 +
 +
=== 运行示例 ===
 +
 +
假设你已经参考[http://wiki.friendlyarm.com/bakebit bakebit教程]安装了BakeBit源代码，<br />
 +
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_SmartLighting.py:
 +
<syntaxhighlight lang="bash">
 +
cd ~/BakeBit/Software/Python
 +
sudo python bakebit_prj_SmartLighting.py
 +
</syntaxhighlight>
 +
 +
=== 运行结果 ===
 +
 +
测试时可用物品盖住光敏电阻模拟环境变暗，或者用手机电筒照射模拟环境变亮，然后观察LED Bar的变化。<br />
 +
LED Bar上被点亮的LED个数由当前环境的光线决定，越暗，被点亮的就最多。
 +
 +
==相关资料==
 +
*[Schematic]([http://wiki.friendlyarm.com/wiki/images/e/e8/06-SCHEMATIC_Light_Sensor.pdf BakeBit - Light 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)

Revision as of 10:53, 13 December 2016

查看中文

1 介绍

Light Sensor
  • BakeBit - Light Sensor是一个光敏电阻模块，主要器件是一个光敏电阻。光敏电阻的制作材料具有在特定波长的光照射下，其阻值迅速减小的特性。
  • 这是由于光照产生的载流子都参与导电，在外加电场的作用下作漂移运动，电子奔向电源的正极，空穴奔向电源的负极，从而使光敏电阻器的阻值迅速下降。在电源激励下，输出端分压减小。

2 特性

  • 使用标准的2.0mm 4 Pin BakeBit接口
  • PCB尺寸（mm）：20x24
  • 模拟信号输出

BakeBit - Light Sensor

  • 引脚说明:
名称 描述
GND 地
5V 电源5V
NC 空
SIG 信号

3 示例程序：Smart Lighting

利用亮度传感器，聪明地控制灯光(灯用LED Bar来模拟)，环境越暗就让灯越亮，环境亮度足够时，就将灯变暗或者熄灭。 本示例需要配合BakeBit - LED Bar使用。

3.1 硬件连接

简单的将BakeBit - LED Bar模块插入 D3 接口，将BakeBit - Light Sensor插入 A0 接口，如下面这样：

Smart Lighting-1.jpg Smart Lighting-2.jpg

3.2 示例源代码

import time
import bakebit
 
# Connect the BakeBit Light Sensor to analog port A0
# SIG,NC,VCC,GND
light_sensor = 0
 
# Connect the BakeBit LED Bar to digital port D3
# DI,DCKI,VCC,GND
ledbar = 3
 
 
lowThreshold = 500
highTreshold = 600
 
bakebit.pinMode(light_sensor,"INPUT")
bakebit.pinMode(ledbar,"OUTPUT")
time.sleep(.2)
bakebit.bakeBitLedBar_Init(ledbar, 0, 5)
time.sleep(.5)
old_color = 0
 
while True:
    try:
        light_count = 0
 
        # Get sensor value
        sensor_value = bakebit.analogRead(light_sensor)
        if sensor_value > highTreshold:
            f=(1023-highTreshold)/4
            light_count =  (sensor_value-highTreshold)/f+1
 
            # turn on ledbar
            color16bit = bakebit.Green
            if light_count > 1:
                color16bit = color16bit | (bakebit.Green << 3)
            if light_count > 2:
                color16bit = color16bit | (bakebit.Green << 6)
            if light_count > 3:
                color16bit = color16bit | (bakebit.Green << 9)
            if light_count > 4:
                color16bit = 0
                color16bit = color16bit | bakebit.Blue
                color16bit = color16bit | (bakebit.Blue << 3)
                color16bit = color16bit | (bakebit.Blue << 6)
                color16bit = color16bit | (bakebit.Blue << 9)
                color16bit = color16bit | (bakebit.Blue << 12)
 
            if color16bit != old_color:
                old_color = color16bit
                lowBits = color16bit & 255
                highBits = (color16bit & (255 << 8)) >> 8
                bakebit.bakeBitLedBar_Show(ledbar, highBits, lowBits)
 
        elif sensor_value < lowThreshold:
            # turn off ledbar
            bakebit.bakeBitLedBar_Show(ledbar, 0, 0)
 
        print("sensor_value = %d light_count =%d" %(sensor_value,  light_count))
        time.sleep(.5)
 
    except KeyboardInterrupt:
        bakebit.bakeBitLedBar_Release(ledbar)
        time.sleep(.2)
        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_SmartLighting.py: 

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

3.4 运行结果

测试时可用物品盖住光敏电阻模拟环境变暗，或者用手机电筒照射模拟环境变亮，然后观察LED Bar的变化。
LED Bar上被点亮的LED个数由当前环境的光线决定，越暗，被点亮的就最多。

4 相关资料

Retrieved from "https://wiki.friendlyelec.com/wiki/index.php?title=BakeBit_-_Light_Sensor&oldid=8326"