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Application circuit of Doppler effect sensor RD627

Published on Jan 20 2011 // Doppler Effect Sensor

 Application circuit of Doppler effect sensor RD627 1

 Application circuit of Doppler effect sensor RD627 2

Application of the Doppler effect sensor RD627
From: Cong Bao lamb Views: 369
RD627 is the use of ultrasound Doppler effect and a sensor made of pieces of moving objects can shift signals into corresponding electrical signals. The device can be widely used in various auto lamps, automatic doors and burglar alarms.
Features RD627-line use of single 7 pin plastic package, Figure 1 is a block diagram of its interior, from the oscillator, transmitter, detector, Doppler signal amplifier, limiter and the power supply circuit and other components. Oscillator generated by the microwave signal by the transmitter sent to an external antenna to the feet of space, resulting in a protection zone of microwave three-dimensional space, when people or other objects moving in the protection zone, the reflected microwave signal with the original signal will produce a frequency shift between, the weak frequency shift signals after the detector to obtain the Doppler signal and then amplified, can be obtained at the foot response to electrical signals with moving targets.
Electrical parameters RD627 Doppler effect sensors typically use the power supply voltage is 12V; effective emitting area greater than 100m2; static pin output voltage of the first 6V; in the effective emission area, when the first goal of moving dynamic output voltage pin Change is not less than ± 50mV, the closer a moving target from the antenna, the greater the output voltage amplitude can be up to ± 5V or more.
Typical Application Circuit RD627 typical application circuit shown in Figure 2, which is a microwave burglar alarm. When people walk around in the net when the output from the ultra-low frequency signals foot buffer by the A2 to the A3, A4 to identify the composition of the comparator. If the signal voltage is the voltage between the two specified comparison, the A3, A4 no voltage output. When the signal is higher than the A3, A4 foot level or lower than the usual electric feet, A3 or A4 output high, the VD1 or VD2 isolation, R6 limit trigger SCR turns on, the alarm bell was electric alarm. SB alarm button for the solution. RP used to adjust the voltage comparator threshold level, which adjusted the alert zone alarm.
Microwave transmitting antenna with a metal wire bent in 3mm 120mm ~ 150mm in the circle can be. A2 ~ A4 available a741 or F006 high-gain integrated amplifier.