Multiplexing Serial Ports - Two Rx pins in to one

I have a transmitter which is connected to two receivers or (detector) modules. I need both of them to detect the transmission simultaneously and send a feedback signal to digital pin 2 on the other Arduino board. But so far I’m able to make only one detector circuit work at a time. If I connect both the detectors to digital pin 2 (as shown in the image attached), a distorted signal is received. So is there any other way of doing this? I’m open to any kind of suggestions even if I have to change the components.

Two photo diodes in parallel (both between pin and ground),
with a single pull up resistor from pin to VCC (3.3volt).
Leo..

Hi,
OPs image;
2e87bfb685baef509b13518743dc277f93bff7ff.png
Tom… :slight_smile:

Hi,
@Wawa circuit.
UNO_PhotoDiodes.jpg

Tom… :slight_smile:

@TomGeorge.
Thanks for posting the diagram.

Don't know why I said 3.3volt.
Must have assumed a 3.3volt Arduino.
If this is a 5volt Arduino, then the resistor can go to 5volt.
Leo..