Intelligent video monitoring terminal circuit module design - circuit diagram reading every day (33)

Industrial Router Crystal 3.2*2.5mm 3225 26M (26.000MHZ) 12PF 10PPM 20PPM 30PPM

AS1360-33-T

L0504-Murata muRata common mode inductor 90Ω 150mA

Video surveillance systems are increasingly entering people's lives. System energy conservation is also an important parameter that electronic systems must consider. For an occasion where there are few people coming in and out, the use of uninterrupted real-time monitoring is not only unnecessary, but also wastes a lot of power. In response to this situation, this paper designed an unattended intelligent monitoring terminal. When no one enters the monitoring area, the monitoring terminal is in a low-energy sleep state; when the infrared sensor detects that someone enters the monitoring area, the terminal is woken up and starts to shoot, and the processed video signal is transmitted to the monitoring center through the network, The central duty officer provides the basis for judgment. For occasions with fewer people entering and leaving, the monitoring terminal can effectively reduce system energy consumption, reduce the amount of data transmitted and saved, and not miss the monitoring object.

Central processor selection

Because the amount of data to be processed by the terminal is large and the real-time performance is strong, the multimedia processing chip TMS320DM642 (hereinafter referred to as DM642) is used. The chip is a newer 32-bit fixed-point DSP from TI's C6000 series of DSPs. The operating frequency is set by the internal multiplier, which can reach 500 MHz, 600 MHz or 720 MHz. The number of executable instructions per second is 4 000 , 4 800 , 5 . 760 MIPS. The DM642 uses TI's 2nd generation enhanced ultra-long instruction set. Its EMIFA interface has a data bus width of 64 bits and a maximum access frequency of 133 MHz. It can be directly connected to high-capacity, low-cost SDRAM chips. The DM642 features three dual-channel (A, B two-channel) digital video ports that can handle multiple digital video streams simultaneously. The DM642 has an I2C interface that can communicate with external I2C devices to configure registers for external I2C devices, the DM642's network port (EMAC interface), PCI port, and HPI port shared pins. Because of its strong processing performance, the peripheral interface is flexible and flexible, and has been widely used in machine vision, medical imaging, network video surveillance, digital broadcasting and other fields.

Infrared sensing signal processing circuit module

The terminal uses an infrared sensor to detect whether there is a person entering the monitoring area. Only when a person enters the monitoring area, the terminal enters the image acquisition, processing, and transmission state. This design uses BISS0001 chip as the core component of pyroelectric infrared sensing signal processing. Its application circuit is shown in Figure 2.

Figure 2 infrared signal processing circuit

In Figure 2, the 7805 is a three-terminal regulator IC that supplies power to the signal processing circuitry. The 9th pin of the BISS0001 chip is the input pin of the trigger control signal Vc. The input voltage should be guaranteed during operation. The resistor R3 can be used to achieve the purpose. When a pedestrian enters the monitoring area, the pyroelectric infrared sensor PIR converts the detected infrared light emitted by the human body into an electrical signal, and sends it to the BISS0001. The signal is processed by the BISS0001 and output by the 2 pin. The output Vo is low. A flat to high transition. If BISS0001 works in the active state and cannot be repeatedly triggered, the high level duration is Ts (Ts=49 152 R1C1). At the end of the Ts period, the output Vo immediately goes from high level to low level and is blocked. TI (TI = 24R2C2) duration; for the case where the active state can be repeatedly triggered (ie, S1 is high in Figure 2), if the change of the input causes the output valid state to trigger again during the previous Ts period, The Vo high level signal will continue for a Tx period from the moment and then transition to a low level and enter the blocking time Ti. During the lockout time, even the interference introduced due to the switching of the load does not change the state of the output Vo. In this design, S1 is connected to a high level, and the output signal Vo of the infrared sensing signal processing circuit is used as an external interrupt signal of the DM642, and Vo is connected to the GP[5:4] of the DM642, and also serves as a power saving mode input of the TVP5150 chip. control signal.