I have some float switches on my aquarium sump that I want to monitor. The wire length is approximately 15 feet between the float switch and the arduino. Is the internal pull-ups on the arduino sufficient for this length of wire or should I use an external pull-up resistor on each line….perhaps something that is a lower value than the internal pull-ups?
Yes, I would use 1K external pull-up to try and keep noise down.
Why change it if you haven't even tested it ? Wait till there is a problem before implementing solutions.
retrolefty:
Yes, I would use 1K external pull-up to try and keep noise down.
That was my thought as well but I wasn't sure if it was overkill. Thanks!
raschemmel:
Why change it if you haven't even tested it ? Wait till there is a problem before implementing solutions.
My current setup uses the internal pull-ups on an arduino nano and I've noticed that occasionally when one of the 120V pumps comes on it will cause some jitter on the line and sometimes it will even fire off the subroutine attached to that particular float switch.
Internal pullups are 50 or 60k . Most people use 10k. SOME people swear by the internal pullups but I can't think of any reason OTHER THAN YOUR APPLICATION to NOT to use the internal pullups. They work fine for MOST applications. I don't think YOURS falls into THAT category.