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dummy55555

New Member
i currently working on this project.

I know that there are several error on the PCB that been drawn.
But i have build the circuit based on the PCB that have been done.

But the problem now is my circuit alarm straight away sound when i on the power supply. I have placed a buzzer(as a alarm signal) between the point 1 and point 9 and connect a resistor with 560 ohm in series.(The resistence value is stated in the project paper) But isn't it the buzzer will still sound when i connect it between the power supply and ground.

In the project paper, it also got stated that a relay can be connected in series with TR1. Izit i have to insert a relay??? If yes, How should i place the relay, there is 5 pins right??

I really appreciate it... Thank you...

ericgibbs

Well-Known Member
i currently working on this project.

I know that there are several error on the PCB that been drawn.
But i have build the circuit based on the PCB that have been done.

But the problem now is my circuit alarm straight away sound when i on the power supply. I have placed a buzzer(as a alarm signal) between the point 1 and point 9 and connect a resistor with 560 ohm in series.(The resistence value is stated in the project paper) But isn't it the buzzer will still sound when i connect it between the power supply and ground.

In the project paper, it also got stated that a relay can be connected in series with TR1. Izit i have to insert a relay??? If yes, How should i place the relay, there is 5 pins right??

I really appreciate it... Thank you...

hi,

You do know that its not really an ultrasonic radar.?

Its an ultrasound movement detector, any distortion of the transmitted/received sound pattern will trigger the alarm.

So if you are moving close to the project it will sound the alarm.

OK.?

EDIT: what type of buzzer have you connected between point 1 and 9..?

Last edited:

dummy55555

New Member
ya, i know that.
I know that this device is used to detect any movement.

But the problem now is my circuit is already sound when the battery is on and there is without any movement at all.

The buzzer i used is very low watt which can replaced with a LED.

ericgibbs

Well-Known Member
ya, i know that.
I know that this device is used to detect any movement.

But the problem now is my circuit is already sound when the battery is on and there is without any movement at all.

The buzzer i used is very low watt which can replaced with a LED.

hi,
Does the buzzer still sound when the switch across points 7 and 9 is open.?

or sound when the P1 pot is turned to the lowest Gain setting.?

or when you connect a temporary shorting link across points 3 and 4.?

Lets know what you find.

dummy55555

New Member
WHy there is a switch across points 7 and 9.
Isn't it the project paper say the point 7 & 8 join together.

And the 3 & 4 is for the receiver right,, after i remove it it still will sound..

ericgibbs

Well-Known Member
WHy there is a switch across points 7 and 9.
Isn't it the project paper say the point 7 & 8 join together.

And the 3 & 4 is for the receiver right,, after i remove it it still will sound..

Yes its 7 and 8.

Make sure 7 and 8 are open and disconnect C11 cap, that should stop the buzzer.
If it dosnt stop, check your wiring for the bottom righthand corner of the circuit diagram.

BrownOut

I hate it when people do this, but now I'm going to do it. I buy these types of motion detectors from Home Depot in a nice, weatherproof housing and common mounting connectors for about US $35. The only thing I have to do to them is convert the 110V ouput to a safer voltage. ( thanks again, eric for helping with that ) As for the circuit diagram, TR3 is drawn improperly. It's not clear how this is supposed to be connected by the diagram. ericgibbs Well-Known Member Most Helpful Member I hate it when people do this, but now I'm going to do it. I buy these types of motion detectors from Home Depot in a nice, weatherproof housing and common mounting connectors for about US$35. The only thing I have to do to them is convert the 110V ouput to a safer voltage. ( thanks again, eric for helping with that )

As for the circuit diagram, TR3 is drawn improperly. It's not clear how this is supposed to be connected by the diagram.

hi BrownOut,
Didn't notice the missing emitter marking on TR3, good catch.!
I expect the OP took TR3 as a npn.?, emitter to 0V.

Make an interesting Sim for LTS.

Regards

mneary

New Member
Other errors in the diagram were spotted last month when we discussed this circuit. There are missing connections, an unmarked resistor, etc.

The discussion should be easy to find.

ericgibbs

Well-Known Member
Other errors in the diagram were spotted last month when we discussed this circuit. There are missing connections, an unmarked resistor, etc.

The discussion should be easy to find.

hi,
Did'nt see that, thanks for the reference.

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