Wiring an Elevator

[kmcclary]

Originally Posted by rocketperson44

Our robot has an elevator lift with a globe motor powered manipulator that could at any time during the match be anywhere from 3 inches to 8 1/2 feet off the ground. We need suggestions on how to wire this motor so that the wires can reach the highest point, but so that we also do not have random wires strewn all over the robot when it is at its lowest point.

I don't know the geometry of your lift, but one thing to consider is running the globe motor wiring through the center of a large bore diameter (1/2" or so) thinwall coiled plastic pneumatic tubing, to create a large diameter "coiled cord". (Be sure to use STRANDED wire, or it'll break!) This is available from most pneumatic supply sources. One end will eventually be anchored to the frame, and the other to the top segment.

For small footprint telescoping column towers, the tubing can be "helix'd" around the entire tower.

For larger, multi-vertical segment tower assemblies with cross braces (like "extension ladder" designs), you may need to use a horizontal stick off of the top segment to hold the upper end of the coil away from the tower's joints.

Running the wire through can be difficult, but can often be done via a "pilot line". First twist the wire pair carefully, to make a nice, even snake to run through the tubing. Note that twisting wire should always be in the OPPOSITE handedness of the strand's twist WITHIN the stranded wire, or it'll kink! You also need to insure the free end of each wire can freely rotate, as they'll need to spin as you twist the wires together.

Now take a thin but strong nylon fishline (or dental floss) attached to a paperwad, and use compressed air to shoot it through the coil. You then use this line to haul the twisted pair back through the coiled tubing (or to step up to a stronger line, and repeat).

The fit between the twisted pair wiring and the tubing's inner bore must be LOOSE or it'll jam partway through, so choose your coiled air line's inner diameter (and the wires to run through it) carefully. The wire gauge needed is defined in the rules, but a wire's insulation thickness often varies widely by wire vendor and/or product line. You'll need to have samples of the wire in hand when you go to find your tubing.

Does this description make sense?

Please let me know if you decide to use this technique! I've done it in the past on some other projects, but would like to see pics of your final config if you decide to use it on your bot. I hope this helped!

- Keith McClary
Chief Engineer, Team 1502 "Technical Difficulties"