model railway signalling

I am about to set up some model signalling.

I am going to use IR beams to trigger signal changes.

I am planning to use a separate DC power supply for the IR emitters. (5V).

This is to minimise unnecessary power through my arduino.

My question(s) is this

  1. Is it good practice to connect the negative of the separate power supply to the GND of the arduino board?

  2. Is it necessary to connect them together?

  3. Are there any pitfalls with such a connection?

(both the supply to the IR emitters and the arduino will be from mains powered, off-the-shelf power supplies) Thanks in anticipation.

If the separate power supply is solely for the IR emitters then

  1. No
  2. No
  3. No

Russell

russellz:
If the separate power supply is solely for the IR emitters then

  1. No
  2. No
  3. No

Russell

Many thanks. Unconnected it is. :slight_smile: :slight_smile:

Hey! How did you go with my code?