The following documentation outlines a hardware design for a video surveillance system. This system provides video monitoring of an environment. The design features a ATSAM3A8CA Atmel SMART-ARM based microcontroller that controls controls the camera and processes the data. This high speed microcontroller was selected such that it could support the 3.6 Mbps UART data transfer from a camera, which is part of a 4D Systems uCAM-II module. The board is to be placed on a small mounting structure controlled by two servos, one for pitch control and one for yaw control. This allows the user to make adjustments to the camera’s viewing angle or to pre program the unit to adjust its viewing angle in a loop to provide full 360 degree surveillance. The servos, which are powered by a regulated 3.3V power supply, can be selected based on the type of mounting structure desired by the user; however, the drive current of the servos must be under 3A. The data from the camera, which is powered by a regulated 5V supply, is collected by the microcontroller for processing. A usb interface was also incorporated in order to allow the user to view the images from the camera on the computer. A programming interface was also included to support JTAG programming/debugging.
The files presented were generated with Altium Designer. The PCB that was designed is a two layer board, with power (3.3V) and ground polygon pours on the top and bottom layers. The regulated 3.3V power supply was selected for the power plane as it contains the largest load, with the servos pulling up to 3A. The 5V supply is used solely for the low power camera with a 90mA supply current. The ground plane was added as a means of reducing noise and preventing cross talk. The board can be powered either from a battery or a power supply with a voltage greater than 6V as both of the board power supplies are regulated with buck converters. Below is a screenshot of the board layout.