AVT841 A

We present a very simple motion detection system. Its basic purpose is to work in car alarm systems and home installations supervising property. It can also be used wherever motion detection is necessary, e.g. as a light switch.
The detector works on the basis of the Doppler effect, i.e. the change of the frequency of sound waves reflected from the moving object. The system works in the range of signals with a frequency of 40kHz (ultrasounds) and therefore completely inaudible to humans. Despite the apparent complications it is very easy to make and adjust. It can be divided into two basic circuits: a transmitter and a receiver with an executive system. The first is responsible for the generation of ultrasound. The second one, receives them, detects a possible change in frequency (i.e., motion within the range of the device) and signals it.

The device is particularly recommended in alarm systems; especially vehicles

Selected parameters:

• the detector works in the field of ultrasound (about 40 kHz)
• two-track system - a separate transmitter and a separate ultrasonic receiver
• the ability to adjust the sensitivity of operation
• operating frequency of the transmitter stabilized by a quartz resonator
• alarm signaling - LED diode
• alarm output - OC type, load capacity 100mA
• possibility of connecting, for example: a relay or attaching a detector directly to the alarm control panel
• built-in power supply stabilizer
• power supply - 12 Vdc
• printed circuit board and documentation included
  A version with a set of components for self-assembly is available
  Detailed description in EP 1/00