I wanted to design a circuit the alarms the buzzer " only when " there is some object/person in the door. the buzzer should stop alarming once person moves away from the position.
I'l be using TSOP1738 and IR LED

What changes should i make to the above circuit?
>>>I wanted to design a circuit the alarms the buzzer " only when " there is some object/person in the door. the buzzer should stop alarming once person moves away from the position.

 

Anyone with the answer?
i want LOGIC 1 at the output.

 

It's not going to work with the TSOP1738.

The transmitter sends out just a 38kHz signal continuously. The TSOP1738 is designed to filter out a 38kHz signal that is constant.

Did you read the datasheet for the TSOP1738?
http://www.datasheetcatalog.org/datasheets/208/301092_DS.pdf

The TSOP1738 is an obsolete part. You should look for an IR receiver that is still in production.

You will need to read the datasheets to determine if the receiver will filter out a continuous 38kHz signal or not.

If you already have a TSOP1738, the transmitter will need to send at least 10 flashes, and then wait at least 14 cycles. One way this might be accomplished is to use a binary counter to divide by 16 driving a flip-flop to enable/disable the LED output.

 

Where did you get the schematic?

 

It's not going to work with the TSOP1738.

The transmitter sends out just a 38kHz signal continuously. The TSOP1738 is designed to filter out a 38kHz signal that is constant.

Did you read the datasheet for the TSOP1738?
http://www.datasheetcatalog.org/datasheets/208/301092_DS.pdf

The TSOP1738 is an obsolete part. You should look for an IR receiver that is still in production.

You will need to read the datasheets to determine if the receiver will filter out a continuous 38kHz signal or not.

If you already have a TSOP1738, the transmitter will need to send at least 10 flashes, and then wait at least 14 cycles. One way this might be accomplished is to use a binary counter to divide by 16 driving a flip-flop to enable/disable the LED output.

okay, i have TSOP1738, should i use timer IC555 IC's both transmitter and receiver for that? what happens if i dont use the IC555 at receiver?

@blueroomelectronics
this circuit is Electronic Watchdog! got it from EFy