Position: Index >

A ultrasonic radar alarm circuit

2016-02-18 02:35  
Declaration:We aim to transmit more information by carrying articles . We will delete it soon, if we are involved in the problems of article content ,copyright or other problems.


This article describes an ultrasonic radar alarm  circuit  theory. The circuit in houses, shops and car security and alarm systems, there are many practical applications. It consists of a set of ultrasound receivers and transmitters that operate at the same frequency. While some fluctuation good coverage balanced circuit circuit interference and the alarm is triggered. This circuit is very sensitive and can be automatically adjusted or reset until manually reset after an alarm is triggered. How it works is because it has been stated the circuit includes an ultrasonic receiver and transmitter both work the same frequency.They use a piezoelectric ultrasound transducer as output and input devices, respectively, and their frequency of operation is determined by the specific device in use. Transmitter is built on tw1o NAND Gates four found in IC3 connection is used here as an inverter and a specific circuit to form a multivibrator output drive transducer. Trimming machine to adjust the output frequency of the transmitter P2 and efficiency should be the same resonance frequency sensor is in use. Receivers use the same signal reflected back to the sensor to receive its output is amplified by the transistor tomb, which is a 741? IC1 opamp. This from 9:00 - 12 VDC and operating circuit can use batteries or a power source. IC1's output is sent to the non-inverting input of IC2 the amplification factor adjustment means P1. The circuit adjusts the balance in such a long stay in the same output frequency transmitters. If there is some movement of the cover signal reflected back to the ultrasonic transmitter and receiver become distorted balance of this circuit is thrown. IC2's output changes suddenly and the Schmitt trigger circuit is built in the remaining tw1o Gates IC3 is triggered. This drives the output transistors TR1, 2 in turn gives a signal to the alarm system or if there is a relay connected to the circuit, in the series of tax TR1, will be activated. The ultrasonic radar alarm circuit is very practical.

1049 ultrasonic radar alarm


1049d ultrasonic radar alarm
 In order to solder a component correctly you should do the following:

@Clean the component leads with a small piece of emery paper.

@Bend them at the correct distance from the components body and insert the component in its place on the board.

@You may find sometimes a component with heavier gauge leads
than usual, that are too thick to enter in the holes of the p.c.

@In this case use a mini drill to enlarge the holes slightly.
Do not make the holes too large as this is going to make
soldering difficult afterwards.

@Take the hot iron and place its tip on the component lead
while holding the end of the solder wire at the point where the
lead emerges from the board. The iron tip must touch the lead
slightly above the p.c. board.

@When the solder starts to melt and flow wait till it covers
evenly the area around the hole and the flux boils and gets out
from underneath the solder. The whole operation should not take
more than 5 seconds. Remove the iron and allow the solder to cool
naturally without blowing on it or moving the component. If
everything was done properly the surface of the joint must
have a bright metallic finish and its edges should be smoothly
ended on the component lead and the board track. If the solder
looks dull, cracked, or has the shape of a blob then you have
made a dry joint and you should remove the solder (with a pump,
or a solder wick) and redo it.

@Take care not to overheat the tracks as it is very easy to lift them from the board and break them.

@When you are soldering a sensitive component it is good
practice to hold the lead from the component side of the board
with a pair of long-nose pliers to divert any heat that could
possibly damage the component.

@Make sure that you do not use more solder than it is
necessary as you are running the risk of short-circuiting
adjacent tracks on the board, especially if they are very close

@When you finish your work cut off the excess of the component
leads and clean the board thoroughly with a suitable solvent to
remove all flux residues that may still remain on it.

@There are quite a few components in the circuit and you
should be careful to avoid mistakes that will be difficult to
trace and repair afterwards. Solder first the pins and the IC
sockets and then following if that is possible the parts list the
resistors the trimmers and the capacitors paying particular
attention to the correct orientation of the electrolytic.

@Solder then the transistors and the diodes taking care not to
overheat them during soldering. The transducers should be
positioned in such a way as they do not affect each other
directly because this will reduce the efficiency of the circuit.
When you finish soldering, check your work to make sure that you
have done everything properly, and then insert the ICs in
their sockets paying attention to their correct orientation and
handling IC3 with great care as it is of the CMOS type and can be
damaged quite easily by static discharges. Do not take it out of
its aluminium foil wrapper till it is time to insert it in its
socket, ground the board and your body to discharge static
electricity and then insert the IC carefully in its socket. In
the kit you will find a LED and a resistor of 560 which will help
you to make the necessary adjustments to the circuit. Connect
the resistor in series with the LED and then connect them
betw1een point 9 of the circuit and the positive supply rail
(point 1).

Connect the power supply across points 1 ( ) and 2 (-) of the
p.c. board and put P1 at roughly its middle position. Turn then
P2 slowly till the LED lights when you move your fingers slightly
in front of the transducers. If you have a frequency counter
then you can make a much more accurate adjustment of the
circuit. Connect the frequency counter across the transducer and
adjust P2 till the frequency of the oscillator is exactly the
same as the resonant frequency of the transducer. Adjust then P1
for maximum sensitivity. Connecting together pins 7 & 8 on
the p.c. board will make the circuit to stay triggered till it is
manually reset after an alarm. This can be very useful if
you want to know that there was an attempt to enter in the place
which are protected by the radar.


ultrasonic1 ultrasonic radar alarm


ultrasonic2 ultrasonic radar alarm


ultrasonic3 ultrasonic radar alarm