Long Distance Pushbutton

[t2]

Controlling a halloween prop about 30+ yards away. Prop1 is at the prop and I have a pushbutton in my hand. No problem on a breadboard, but don't know if the distance changes things.

Should I have the input low and the pushbutton makes the input high or vice versa? Will the 5 volts work or do I need a different solution due to voltage drop? Any assistance in understanding the problem is appreciated.

Terry

[menehune]

I would recommend as large a wire size as possible-18 gauge or larger.  A piece of Cat5 cable probably will not work due to the small wire size (24 gauge) and high wire resistance.  If you want or need to use a small wire gauge cable, you could run 12 volts down the line to the switch, hooked to the relay coil.  You would then be switching a relay on/off which would turn on/off the 5V into the prop pin.

I tried to run a security camera on the top of a three story building once using 18 gauge microphone cable.  The 12 volt input on the ground floor was turned into 9.5V at the camera due to the wire's voltage drop.

Go with as big a wire as possible and as high a voltage as possible to reduce the voltage drop in the cable.  That is why long distance power transmission is in the 100s of thousands of volts (if not millions) and not at lower voltages.

You can compare voltage drops using online voltage drop calculators.  Unfortunately, most are for AC power line voltage (120v, 240v, etc).  Here is one for DC.  With a 0.25A current, 30 foot, 24 gauge conductor, you get a 0.4V drop in the circuit.

[JonnyMac]

I'd be a little leery to connect that much wire to the input of a Prop-1, no matter what the gauge.  You could power a relay (located near the Prop-1) with the N.O. relay contacts acting as you remote button.  Per the post above, however, you still need to size the wire appropriately.