[SOLVED] Help me in a LASER alarm circuit

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archis1991

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I have a schematic of a LASER alarm which can active when the laser beam braked by something. And remain on until reset button is pressed.
Here is the schematic...



But the there is a problem in the diagram.... I don't know what... May be in the switch connection or something else..
Please help me to fix this or any other idea to build the alarm ....
 

Forget this circuit. Explain what you actually want (functionality) in whatever you wish to design.

If you want a laser circuit that rings an alarm when the beam is cut, you can use a simple laser detector connected to a low signal triggered circuit connected to a buzzer.

Something like what I have attached would help.

But explain what you want your circuit to actually do for other members to give some help.
 

Is that L14F1 is a photo transistor ??
Any way i used a photo transistor and a LDR but in both case ... The buzzer went off for a few second whether there was a laser point on it or not then stopped ....
SO the circuit didn't work ....
 

Finally I make the circuit ..... A LASER Alarm .... Which can goes off if the laser beam is broken and don't stop until someone press the reset button ....
Here is the schematic for every one ....


How it works ??
Well for that more three pictures ...
First Power on ...

Then broke the beam ...

And then in order to stop the alarm press the reset button ...


You can use a push switch as a reset button

The PNP transistor can be any Common PNP transistor like ..2N3906 or 2N4403

You can use 2N3904 or BC548 or 2N4401 instead of 2N2222A

and also you can use IN914 diode instead of IN4148.....

Thank You ......
 

Photo transistor uses the light signal on the base to control the transistor operation. Thanks for sharing your circuit also.
 

U r asking or telling ?
If u r asking then yes the ground pin of ic (which is pin 4 for LM741 IC) is grounded but no need to connect the pin 8 to ground .
 

U r talking about the first schematic ..... Ok I don't know about it ... It is not mine ... i just found it from a website , tried to make but failed ....
 

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