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Product Review The “Wachit” Smart Video Motion Detector turns an ordinary VCR/ DVD-R into a security event recorder. A built-in learning infrared remote is used to control the recorder. After a simple setup procedure, all you need to do is hook up the video cable and position the supplied infrared emitter in front of the recorder to begin recording events. “Wachit” – it turns a By MURRAY DOWNES* VCR into a security recorder E VERYONE IS FAMILIAR with the passive infrared and microwave sensors that are used to activate door openers, security lights and alarm systems. Less known is the existence of devices that use image processing to detect motion and trigger alarms, recording and other actions. These are generally referred to as Video Motion Detection (VMD) sensors. Whereas a PIR or microwave sensor has a limited range, VMD sensors can function over very long distances and wide areas because they work from a video camera image that could be viewing anything from 3m to 5km away. Farco Technologies Limited manufacture high-end video motion detection systems that are used in red light cameras and traffic signal controllers. They also produce a range of low-cost *Murray Downes is the Sales & Marketing Manager for Farco Technologies, Ltd. 46  Silicon Chip VMD devices that utilise high-speed image processing technology. The “Wachit” is a small, sturdilyhoused unit that’s connected between a video camera and a recording device. It comes equipped with relay outputs and can directly control a recording device via its inbuilt infrared remote learning capabilities. Farco also offer the VMD-19 module for those that wish to use VMD technology in their own products. The module consists of a small printed circuit board with the same footprint as a standard 18-pin 0.6-inch wide IC. It can be directly connected to a composite video source to detect the motion of objects within the video signal. From the outset, Farco designed the VMD-19 for easy integration in security cameras, VCR designs, video switchers, quad processors, multiplexers, etc. VCR surveillance When integrated with a VCR, the VMD-19 transforms it into an intel- ligent motion-detecting surveillance device. When motion is detected within the video signal, the VCR automatically starts recording the scene. Once the motion ceases, the VCR stops recording. This avoids hours of recording of non-eventful static images. With video motion detection, there is no need for the additional cost The VM-19 module consists of a small PC board carrying a single IC and a number of tiny surfacemounted components. The complete assembly is the same size as a standard 18-pin 0.6-inch wide IC. siliconchip.com.au and complexity of external triggering devices. False alarms that can be triggered by camera noise are largely eliminated in the VMD-19. This technology creates an ongoing role for those VCRs that have been made redundant by DVD players. By incorporating Farco’s low-cost IC into their circuit designs, electronics enthusiasts now have the means to develop state-of-the-art security/ surveillance systems. The VMD-19 is not just limited to controlling video recorders and can also be put to work in a multitude of trigger and/or indicator applications. Here are just a few possibilities: • video loss detection • security light switching • alarm system enabling/disabling • gate and door monitoring • lighting control in storage and utility areas, stairwells, works of art, car parks, freight holding areas, etc. As well as the obvious home security applications, the VMD-19 has also been used to trigger recording and remote alarms for monitoring wild life (eg, nesting sites). For more information, contact Murray Downes on +64 3 374 5534 siliconchip.com.au Fig.1: this simple circuit demonstrates the capabilities of the VM-19. The composite video signal is fed directly into pin 18. Sensitivity is determined by the logic states of pins 12 & 13, here connected to a 2-way DIP switch. When motion is detected in the video source, pin 14 goes high, illuminating the LED. In an application circuit, this pin would be used to control external recording and/or alarm equipment. or email sales<at>farco.co.nz. You can also write to Farco Technologies Ltd, 200 Armagh Street, Christchurch, NZ. Product datasheets and online sales are available from their website at SC www.farco.co.nz September 2006  47