I will be attaching buttons as input to my Arduino and I want an indicator LED to know when the button is pressed. However I want LED functionality wired directly to the button - not controlled via Arduino digital output.
My first thought was to simply wire the LED in parallel with the digital read circuit (10kOhm pull up resistor). (See left figure).
But I realised I could simplify the circuit on the right and simply use the LED with its resistor as my pull up resistor for the digital read pin. (See right figure)
I think this should work but I just wanted to check quickly - is there any reason this might not be a good idea?