Convert Wireless door bell to sensor

Hi.
My friend wants a sensor on his door so when people enter they trigger the door chime.
I picked up a $8 wireless door bell which has a simple push button on it and uses a mini (23a) 12v battery.

Is there anyway to make this so it produces a sensor line across the door so when someone enters it breaks the sensor and triggers the doorbell?
i have seen them somewhere else where its a reflector plate and a sensor.
Any schematic would be appreciated. Also i do have acccess t bigger power supply / more batteries if needed.

cheers
Stuart

There are plenty of ways to go about it. A simple solution might be to start with a kit like this. The linked to PDF does show the complete circuit(s) for the kit.

Then if the existing doorbell needs to be used for wireless transmission the button would have the normally open contacts of the receiver relay placed in parallel with it. It's all about how you choose to simulate a button push of a doorbell button.

Ron

discostuee said:

Is there anyway to make this so it produces a sensor line across the door so when someone enters it breaks the sensor and triggers the doorbell?
i have seen them somewhere else where its a reflector plate and a sensor.
Any schematic would be appreciated. Also i do have acccess t bigger power supply / more batteries if needed.

Click to expand...

You will definitely need a bigger battery or a wall wart. A beam break detector will have to run 24/7. The door bell battery is used only for a brief transmit.

Ken