Dual Video Switcher for Surveillance
Created: Sep 29, 2014
No description available.
Video surveillance is the monitoring of any activity on a designated area with the use of a video generating device. Most users are purposely install this device to monitor their security, direct their business, and manage their area of responsibility. A single surveillance camera has the disadvantage of "blind spot", which hinders the user to see some of the desired areas. To solve this problem, another camera must be installed to negate the blind spot.
This project has the feature to use two cameras with only one monitor; it swaps from two video sources with specified time interval. A 555 timer IC is used is to set the time of the switching interval between video A and B, which in this circuit, the time is set to two seconds. The IC used in the switching stage is the HEF4066B analog switch; a four single-pole, single-throw analog switch functions. Each switch has two input/output terminals (nY and nZ) and an active HIGH enable input (nE); when nE is HIGH; the analog switch is turned ON.
Analog switches 1 and 4 of the HEF4066B are connected to the two video inputs, which are driven by another two analog switches 2 and 3 of the same HEF4066B. The generated control signals of the switches 2 and 3 are 180 degrees out of phase. The two 5kΩ variable resistors located in the amplifier's stage are used to adjust the contrast and brightness of the monitored video.