Your drawing is close. This link illustrates examples of using a pull up and pull down resistor with a MCU. You write your code accordingly for a pull up or pull down. The receiver board has a jumper to choose when the receiver output is active. As mentioned above the resistor value can be 10K or as shown in the link 4.7K really not critical, either will work.

Ron

 

Got it

 

Referencing the circuit in post#17, I wonder if that "COM" terminal is tied to other than the relay contact common. Why else would the assembly have the two supply terminals AND a common terminal??

Post #17 only reflects two supply terminals (+ and -). The image shows the transmitter and the receiver, two separate units. Transmitter + and - and receiver + and -. The Com and Out are just a switch and in the drawing they tie switch Com to power - or ground. That is an external connection so in the example they switch Com.

Ron

 

Got it
View attachment 265658

Not quite. With that configuration the Com would go to Ground not VCC. When the switch is active the out would be a logic low and when the switch is not closed the out a logic high. You write your code accordingly.

Ron

 

@Reloadron:

The circuit in #22 is correct. The resistor that looks like a pull-up is comnected to a ground symbol.

Bob

 

@Reloadron:

The circuit in #22 is correct. The resistor that looks like a pull-up is comnected to a ground symbol.

Bob

Thanks Bob, looking at things upside down. Yes, that will work. My bad.

Thanks
Ron

 

Ok, In this case what would be logic value on MCU pin when object is detected? what would be logic value on MCU pin when object is not detected?

 

High when detected, low when undetected if the sensor is used in normally open mode.

Bob