Hey folks, just need to make sure I'm not wrong on this and would appreciate another pair of eyes on this.
I have pins on my Arduino that will be set to INPUT_PULLUP. I'd like to be able to pull those pins low through some toggle switches on a little panel that I intend on mounting far away (let's assume 50 ft). I was thinking of running cat5 between the Arduino and the panel and using RJ45 connectors and sockets to interface and do the hardware.
The concern is how far away the panel is and how I'd be using Cat5. I have 4 pairs of 24 gauge solid wire. I've read that the internal resistor is at 20k ohms(I've seen 20k-50k, so I'm going to figure off 20), which means the Arduino is drawing 0.25mA just keeping the pin pulled high.
Calculating 100ft round trip, with 24 gauge wire, it seems like the voltage drop (at 1mA draw, which I'm rounding up to), would result in only 0.1% voltage drop, which is negligible.
So, I'm under the impression that there would not be any problems doing this. I'm not sure I see any problem with getting only 1 wire from a pair and using that as the ground and then having up to 7 switches.
Anyone see any reason that I would have an issue doing this?