BIG prob

[buland]

after so much of "parishram"....all i ended wid was crap...........
'm making one of those infra-red intruder alarms.....and my reciever module is in a perpetual state of sirens n lights.......i tried each n every waqy to allign my reciever n transmitter modules....but the reciever continuously sounds an alarm..........do you think it might b one of those probs where the light emitted by my infr-red diodes isn't sensed by my photo-diode??????...or is it that a photo diode can sense any light (infrared) emitted by any diode(infrared).....jus in case u wanna know....my photo diode is : tsop 1738

(if u r wondering wat that word "parishram" is....its a sanskrit word for geniune, committed hard work.........)

 

[lord loh.]

I tried something using IR too....

I guess you are using a transistor to amplify the TSOP 1738 signal....The problem might lie here....The transistor might invert your signal....


The other common problem with TSOP 17xx is false start.

When you power on the sensor, It gives one output pulse irrespective of input. The solution is to use a slow starting circuit using a 555 (several EFY projects use them https://www.efymag.com/)

You probably have a Flipflop to latch in the event. This might be causing the false start to latch in....

 

[buland]

hmmm......

yer...i get da probs...but wats da solution??????

 

[lord loh.]

A test to know if your problem is due to TSOP 17xx fake start:

Reset your Flip flop once the perpetual alarm starts. Reset only the flip Flop. NOT the power to your TSOP 1738 or another fake start shall be generated.

If the alarm stops after resetting the flip flop, the fake start hypothesis is confirmed.

Solution : put a 555 timer IC to activate the flipflop after say 100ms of powering on the circuit. So the flip flop shall remain deaf to the initial fake start. (Monostable multivibrator/one shot)

Suppose it is not a fake start check if your amplifing transistor that amplifis the TSOP 1738 signals is inverting or not...

DO tell us what happened by the solution....

 

[buland]

err.....

errr..... i know it might b silly to ask but wats a flip flop n how to reverse it???.......
P.S: srry to take so long to reply...actually i had given away all my hopes on dis project ....see if u can enlighten me up...... :idea:

 

[lord loh.]

Re: err.....

errr..... i know it might b silly to ask but wats a flip flop n how to reverse it???.......
P.S: srry to take so long to reply...actually i had given away all my hopes on dis project ....see if u can enlighten me up...... :idea:

Looks like you have got a kit and are trying to assemble it ?

A flip flop is a memory element. COuld be an IC or may be a combination of 2 transistors. As you design it..... It has two inputs SET and RESET and two outputs Q and Q'

When SET is 1, Q=1&Q'=0
When RESET=1 Q'=1 and Q=0

So just exchanging wires would do....

Anything more I could tell you ? I 'll be glad.

 

[buland]

thnx....... but i'm no aseembling a kit

 

[pink_scarf]

I need to make a burglar alarm with an LDR and IR sensor..please advise me the circuit diagram if possible
Thanks

 

[DerStrom8]

I need to make a burglar alarm with an LDR and IR sensor..please advise me the circuit diagram if possible
Thanks

Please do not post your own question on someone else's thread. It tends to cause confusion and is not very polite

EDIT: I see you have your own thread now, which is good. Check back there for answers.