灯光控制系统电路

2011-05-19 18:36:45来源: 互联网

灯光控制系统电路,ht Control System

It is easy to install a couple of infrared emitter and receiver at the entrance of your room and maybe you connect them to the light, but you cannot control the light in this way! You will never know how many person inside and if the room is empty or not. In this system, every thing is under control, because it is smart enough to know how many persons inside; and it can identify the direction of them, so the light will be turned OFF when the room is unoccupied; and ON otherwise! This tutorial will show you how.

Theorem of Operation:
As shown in Figure 1, Light Control System has five units:
1- Power supply to convert 240V AC into 5V DC.
2- Sensing units that convert body motion into analogue electrical signals.
3- Analogue comparator to convert analogue signals into digital signals.
4- Microcontroller to process these digital signals and send the appropriate command to the room light.
5- Relay to act as an interface between low voltage (control system and sensors) & high voltage (room light).

Sensing unit consists of infrared emitter OP295 to produce the infrared beam, & two detectors in front of the emitter to detect the infrared beam OP598. Since the main idea in this device is to know person direction; and so, to get this approach, we have to use tow pieces of infrared detector in order to

  A

Detectror

B

Detector

1   

 High

High

2  

 Low

High

3  

 Low

Low

4  

 High

Low

5  

 High

High


 Tip:
If you have a camcorder, or just a camera mobile phone, you can see the infrared light! Just point the infrared emitter at the camera then you will be able to see the infrared light in the viewfinder. If you point your remote at the camera and push a button, you will see flashing light!

identify the direction of the person as shown in Fig 2.


When Infrared beam become broken due to any body, the output signals from these detectors will be changed in unique sequence. Controller will identify the direction of the person by analyzing these signals as shown in the table at right "from 1 to 5 passed IN, 5 to 1 passed OUT":


Since detectors output signals are analogue while the controller can only process digital signals, these signals must be converted to digital through the analogue comparator LM393.

Controller will increase the number of the persons in side the room by one, or decrease it by one when the appropriate sequence of signals have occurred. If this number is greater than zero, light will be turned on otherwise it turned off.
After this, controller will stop scan sensors for one second to allow the whole body to pass. Fig 3 describe the whole algorithm

Sensors circuit is so sensitive in Light Control System, that mean any external noise or any small variation in voltage will change the sensors circuit status. While these signals are changing due to these reasons, microcontroller will assume that some one pass in front of sensor and so a fault will occur. In order to solve this problem I have used soft and hard components "capacitors" to make Light Control System stable as much as possible. A soft component is an algorithm in the control code to separate the noises signals from the real signals.



  Notes:
- You have to isolate detectors from any kind of light, except the infrared radiation.
- Use TIP110 to drive relay current; it has Base-Emitter Shunt Resistors built in. Diode D1 is acting as a freewheeling diode.
- Analogue reference voltage should be less than voltage produced by the detectors; otherwise, the system will not function properly . "Less than 0.1V is recommended"
- The maximum speed of the body to be detected by the Light control System is 1.67 metersecond = 0.462 KmHour this value is accurate only if the depth of the passing body in front of sensors is equal to the distance between these two infrared receiver, if this depth is more, the maximum speed will be increased.
- Light Control System is unable to detect any body with a depth less than the distance between 2 receiver.
- By adding an auxiliary switch, Light Control System can be disabled if any failure has occurred after installing. This auxiliary switch disables the functionality of Light Control System and restores the wall light switch to the previous state as shown in figure 4. 

 

 


关键字:灯光控制系统  电路

编辑:eeleader 引用地址:http://www.eeworld.com.cn/gykz/2011/0519/article_6041.html
本网站转载的所有的文章、图片、音频视频文件等资料的版权归版权所有人所有,本站采用的非本站原创文章及图片等内容无法一一联系确认版权者。如果本网所选内容的文章作者及编辑认为其作品不宜公开自由传播,或不应无偿使用,请及时通过电子邮件或电话通知我们,以迅速采取适当措施,避免给双方造成不必要的经济损失。
论坛活动 E手掌握
微信扫一扫加关注
论坛活动 E手掌握
芯片资讯 锐利解读
微信扫一扫加关注
芯片资讯 锐利解读
推荐阅读
全部
灯光控制系统
电路

小广播

独家专题更多

富士通铁电随机存储器FRAM主题展馆
富士通铁电随机存储器FRAM主题展馆
馆内包含了 纵览FRAM、独立FRAM存储器专区、FRAM内置LSI专区三大部分内容。 
走,跟Molex一起去看《中国电子消费品趋势》!
走,跟Molex一起去看《中国电子消费品趋势》!
 
带你走进LED王国——Microchip LED应用专题
带你走进LED王国——Microchip LED应用专题
 
电子工程世界版权所有 京ICP证060456号 京ICP备10001474号 电信业务审批[2006]字第258号函 京公海网安备110108001534 Copyright © 2005-2016 EEWORLD.com.cn, Inc. All rights reserved