burglar alarm with IR sensor

I need to construct a burglar alarm with an IR sensor and LDR for an electronics project.
I can make 2 separate circuits or combine them as one. However I need a circuit diagram to start building it.Please help me.
Thanks

pink_scarf said:

I need to construct a burglar alarm with an IR sensor and LDR for an electronics project.
I can make 2 separate circuits or combine them as one. However I need a circuit diagram to start building it.Please help me.
Thanks

Click to expand...

Hi, pink_scarf. Welcome to ETO!
I'm not sure quite what you mean--You want to use an IR sensor AND an LDR? Those are two different types of sensors. Perhaps you meant an IR sensor and an IR emitter? A bit of clarification could be helpful here
Der Strom

nope..thats not what i meant..the ir led & ir reciever is a separate thing and the ldr is a separate thing..
i need a circuit which incoporates both IR and LDR.
If i dont get it i'll just use 2 separate circuits one with the LDR and one with the IR
Please let me know in case u come across a burglar alarm circuit which meets the specifications

Thanks

Sorry thats still not very clear, I imagine the IR emitter and receiver would be a "beam break" type of alarm.
But what is the LDR for ?

Brevor said:

Sorry thats still not very clear, I imagine the IR emitter and receiver would be a "beam break" type of alarm.
But what is the LDR for ?

Click to expand...

hi Brevor,
I think what he is asking for is a combined detector that uses an IR detector and LDR detector, in series or parallel, which gives an output if either, or both of the detectors is/are obscured from the remote IR emitter.???