help please to create a digital circuit

[gonajenia]

We want to design a system that sounds a buzzer inside our home whenever motion outside is
detected at night. Assuming we have a motion sensor with output M that indicates whether
motion is detected (M=1 means motion detected) and a light sensor with output L that indicates
if light is detected (L=1 means light is detected). The buzzer inside the home has a
single input B that when 1 creates a loud warning sound. Using AND, OR, and NOT gates,
create a simple digital circuit to implement the motion detector at night system.

 

[Jestin_cubetech]

Y= M OR L
M= PIR Motion Detector [active high logic]
L= LDR [active high logic]

 

[gonajenia]

In circuit that you give there is only NOT gates. Am I right? and where are the AND and OR gates?

 

[Jestin_cubetech]

7432 Quad 2-Input OR Gate.

 

[gonajenia]

Thanks for your help. And can I ask 1 question?
How can we know that it is the motion detector at night system.?

I know about it a little and I want to understand... please if you can , tell me

 

[Jestin_cubetech]

PIR Motion Sensor working :https://www.ladyada.net/learn/sensors/pir.html