I have some home automation, and want to put a
rain sensor far away (about 30') from my computer.
(EDIT: Rainfall meter or rain gauge, not a sensor. as per Transistor)
The sensor uses a mechanical teeter-totter with a magnet that momentarily triggers a reed switch as it tips.
I want to use the reed switch to set a flip-flop (74?109) that the computer can read at its leisure, then I want the computer to clear the flip-flop.
Do I put the flip-flop far from the computer and near the sensor running Vcc, Gnd, Clr, & Sens, or put the flip-flop near the computer only running the reed closure through the wire?
Reliability, of course, is paramount. I am thinking noise issues, and impedance.
My arguments for each case...
If I put the flip-flop near the reed switch, the reed switch will reliably trigger the flip-flop, but there may be a lot of noise on the clear line triggering false clears.
On the other hand, putting the flip-flop close to the computer will make that reliable, but the 60' of wire may not trip the flip-flop as the magnet goes by. Also, there may be noise on that line and may trigger false sets.
In either case, I have lots of old 4-conductor telephone (CAT3?) cord.