Research And Development Of LED Video Curtain Wall Protector

LED with low power consumption,long service life,high brightness and other features,is widely used.Both the clarity and resolution are very high when LED video curtain wall plays video advertisement, the video content is clearly visible even in the sunshine,then the LED screen usually be used to broadcast video nimation for stadium and buildings in the city.LED video curtain wall is generally installed in the external wall of buildings,the insulation shell of video wall will eventually break and water can flows into the video wall after a long time,therefore,a fire accident will be caused by the short circuit,and it will threat to the safety of life and property.lt is important to research and develop a set of LED curtain wall protector in order to reduce fire accidents caused by the video wall combustion.The protector can monitor the video wall running environment arguments that inlude temperature and humidity and somke solubility,but also can monitor the phase line current and the zero line harmonic current real-timely,and it has the function about SMS warning and remote controling.The existing protectors only take steps for leaking current and short circiut,based on the shortage of the existing protectors,Monitoring the zero line harmornic current of the power supply system and using a mobile network for SMS alarm are put forward to be as innovations.The main research work of this paper includes the following points:(1)the Linux operating system transplantation based on ARM platform.Protector need monitor the running environment arguments(temperature and humidity and smoke solubility) and the running state arguments(current),it can guarantee the stability of he system and the multitasks coordinate each other under the influence of the operating system.(2)transplantation about QT interface.QT interface as a GUI interface,not only can display the data from system background monitoring dynamically,and also provide the touching function;users can easily interact with the system by QT interface.(3)short messages warning and alarm function. Single chip microcomputer as the auxiliary controller system, driving the GSM module by the serial port,make the GSM send warning messages to users, and users can send control commands ON and OFF for switching the power supply system.The protector can power down automatically to reduce the fire accident when the system status or environment is abnormal.(4)the underlying driver sensor module.Smoke sensor and current sensor data are got through ADC module,in the underlying driver,ADC driver belongs to the character device driver,and it will be added into the kernel after compiling,the file system will exist the device node at the same time. Temperature and humidity sensor communicating with ARM through the I2C bus,which belongs to the platform driver,when it added into the kernel will provide the device node for application layer.(5)the analysis on zero line harmonic current.To analyse the harmonic current depending on the data from ADC sampling from current sensor,designing a FFT algorithm,which can get the zero harmonic current RMS;comparing the harmonic current with the threshold,the protector will determine whether for sel-protection or SMS warning.