Question about the connection

Thread Starter

Tommy Lee_1489743474

Joined Mar 17, 2017
39
Motion-Detector-Circuit-Diagram.jpg
Basically there are few questions i want to ask
1) For the transmitter circuit set the frequency to 5kHz?
2) Is the capacitor (100uf) before the speaker is necessary?
3)Is the capacitor (0.01uf) for the NE555 timer's pin5 is necessary?
4) Does resistor is necessary to place before the collector of the phototransistor to prevent damage?
5) can i use 9v battery?
6) Can i add a relay at the receiver pin3 to operate a light bulb?

Problems after i connected the circuit
1) The led is keeps turned 'ON' no matter what. Isnt it suppose to turn off when both ir emitter and phototransistor is facing together? Even i changed the reset pin to ground to reset the circuit. After that, i realized the NPN transistor and phototransistor is damaged i don't know why. :(

Notes:
I brought the ir emitter and phototransistor is both 940nm from KINGBRIGHT :D The picture is not very clear and sorry for my english haha

WEBSITE: http://www.electronicshub.org/motion-detector-circuit/
 

AlbertHall

Joined Jun 4, 2014
8,187
Yes, there should be a resistor in the supply to the collector of Q1 to limit the possible current. The value is not critical, perhaps 4.7k to 47k.
Also if the 100k pot connected to pin 7 of U2 is set to zero then U2 may be damaged. Add a resistor, perhaps 1k, in series with the pot.
 

Thread Starter

Tommy Lee_1489743474

Joined Mar 17, 2017
39
Yes, there should be a resistor in the supply to the collector of Q1 to limit the possible current. The value is not critical, perhaps 4.7k to 47k.
Also if the 100k pot connected to pin 7 of U2 is set to zero then U2 may be damaged. Add a resistor, perhaps 1k, in series with the pot.
So the circuit connection is alright..just need to add some resistors? :D
 
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