How to wire unrealistically well?

[BJT]

I think it takes one person who understands the goal and is also absolutely 100% in charge. Wiring can go from neat to "good enough we're in a hurry" in a split second. There has to be someone to keep that from happening.

[bbradf44]

This is probably an obvious one but test all your electronics(jags, tallons, victors..) Before you wire them to the robot. This year we went from having some of the neatest wiring we've ever had to the worst days before bag because we discovered a fried jag in testing and had to replace it last minute

[RKazmer]

Originally Posted by bbradf44

This is probably an obvious one but test all your electronics(jags, tallons, victors..) Before you wire them to the robot. This year we went from having some of the neatest wiring we've ever had to the worst days before bag because we discovered a fried jag in testing and had to replace it last minute

Or you can plan for a talon or jag to burn up and have an easy way to remove and change the components. Quick disconnects are a very easy way to keep switches simple and easy and having all of the wires ziptied to something other than the talon or jag itself will keep the wire from going everywhere when the talon or jag is pulled out.

[evanperryg]

My team uses the Autodesk wire harness environment to lay out our wiring before actually running the electrical system. Also, I suggest doing your wiring in a way that will make it easy to replace a component/wire. The biggest mistake you can make is to put too many tie points, zipties and velcro strips in your design. Sure, a big bowl of wire pasta is bad, but if you have to cut 100 zipties just to replace a faulty cable it's just as bad. If you're interested, I have a spec sheet on our 2014 electrical system, which lays out design decisions and has some screencaps of some of the CAD work.

[SteveGarward]

Originally Posted by iKiel2012

One thing that my team, 1073, has had problems with in the past is that the electrical portion of the robot isn't in mind when the mechanical aspects of it are being designed. Make sure both of those groups can figure out a design that works for both...

It happens to us all. This year we had the least space we've ever had. It ended up being one of the neatest jobs ever, out of necessity. It also ended up being one of the least accessible ever, so thankfully nothing went wrong! We also wired it in the shortest time we've ever taken - 9 hours, start to finish.

The key is to get the WHOLE TEAM to understand that you are designing and building a robot, which is a complete system - not just a collection of mechanical assemblies stuck together.

[connor.worley]

Originally Posted by evanperryg

Sure, a big bowl of wire pasta is bad, but if you have to cut 100 zipties just to replace a faulty cable it's just as bad. If you're interested, I have a spec sheet on our 2014 electrical system, which lays out design decisions and has some screencaps of some of the CAD work.

I have to disagree on this. If you fail a cable during competition, just unplug both ends, throw a spare cable in, and tie it down. Leave the dead cable on the board and replace it when you get back form the competition.

It's tedious, but nowhere near as bad as spaghetti wiring, which is much more at risk to fail.

[nixiebunny]

We had a very nice wiring setup this year. Three things contributed to this.

The first was to have enough room for the wires to lay flat on the belly pan. We did three iterations of parts placement to get one that fit well. Then we cut it on a laser cutter from 3/8 plywood. The main thing in parts placement is to put the motor controllers between the PD board and the motors, so you don't need to make long wire runs! We used Talons and lined them up in two rows, one on each side of the PD board.

The second is to wire the power stuff with wire that's just long enough, and force it to lay flat against the belly pan. Make the corners square, so it looks neat. That trick by itself is 90% of the secret!

Third, we wired up the PWM and sensor wires on a second layer "floating" above the power wires, using a series of 1" long Vex standoffs and P-clips to support the wires over the power wires. This made a clean package of those wires that usually go all over the place.

The result was that our robot won two engineering awards and was shown to other teams by the inspectors as an example of how to do it right.

[evanperryg]

Originally Posted by connor.worley

It's tedious, but nowhere near as bad as spaghetti wiring, which is much more at risk to fail.

Yeah, too many tie points is better than not enough, but too many becomes a major hassle especially when replacing a component (less flex in the wires, they get in the way more). That isn't to say you should do bad wiring, in fact I take great pride in the quality of my team's electrical work. But even with excellent wiring, parts will fail, and the design should be centered around making part replacement as pain-free as possible.

[wireties]

There are a lot of great looking harnesses in this thread!

It is not magic - there are guidelines to produce a good wiring harness. My company makes racks of equipment used on airplanes and ships (where vibration is a huge concern). Without quoting all the relevant standards, here a a few quick helpful rules to (try to) follow:

- Of course be safe - follow the FIRST rules for wire size and color
- Always use the correct tool to crimp any terminal or pin
- Test each crimp physically (pull on it) and electrically (with a meter)
- Use wireties at every point that a wire or cable leaves or enters a bundle
- Use wireties at least every 6" along a bundle
- Secure the bundles to a guide or structural member
- Wire "orthogonally", run wire and cables straight in and out on X, Y and Z planes (no running wires diagonally across an open space)
- Wireties near an endpoint (connection) should leave a short loop or curve near the connection for strain relief - you want these wires to move some with vibration but not in a way that loosens the connection
- Wireties on the bundle should firmly secure the bundle to the structure - you do NOT want these to move
- Do not exceed the bend radius of any cable or wire
- Do not run wires through a hole (in metal) without protection like grommets or heat shrink or sleeves of some sort (so vibration does not wear the insulation and short the copper to the metal)
- Label every wire at both endpoints
- Document your wiring harness (FIRST already gives you a drawing of required wiring)
- Plan ahead so you have room and mount points for the wires and wireties
- Do much the same thing with your pneumatics

Good luck!

[evanperryg]

A few more things:
-Get a hydraulic crimping tool and the terminals to go along with it. Not only do these look really good once they are heatshrinked, they are impossible to pull apart.
-Wire sleeve, use it. It's simple plastic tubing that goes around wire bundles. Keeps everything together, and protects wires from moving parts.
-Make sure your labeling makes sense. Have a key if your labels only use colors or letters.
-Where you can, use velcro straps instead of zipties. Easier to remove, easier to replace.
-Heatshrink is your friend. Use it.

[RKazmer]

Originally Posted by evanperryg

A few more things:
-Get a hydraulic crimping tool and the terminals to go along with it. Not only do these look really good once they are heatshrinked, they are impossible to pull apart.

This is where you can find the hydraulic crimping tool we have used for the past two years. It works best with metal-only terminals, but it will do plastic covered terminals as well.
http://www.harborfreight.com/hydraul...ool-66150.html

One note about this tool: It does rust if left out, so make sure it gets put away as well as oil it every two to three weeks depending on the amount you use it.

[evanperryg]

Originally Posted by RKazmer

This is where you can find the hydraulic crimping tool we have used for the past two years. It works best with metal-only terminals, but it will do plastic covered terminals as well.
http://www.harborfreight.com/hydraul...ool-66150.html

One note about this tool: It does rust if left out, so make sure it gets put away as well as oil it every two to three weeks depending on the amount you use it.

This is the one we use, and since getting it we don't even use shielded terminals any more.

[M.Kong-Sivert]

Last year, our team started color-coding our wires. We bought several colors of electrical tape and wrapped a piece around a wire every time it was connected to something else. It made the wiring much easier to follow.

[kstl99]

Wiring is so important, not just to look good but to be able to work around it without catching wires with your fingers or tools. Good wiring will not come apart at the worst time during a match (except PWM cables). And good wiring will make it easier to troubleshoot and replace faulty components.

Wireties' list is great and includes almost all the things I would have mentioned. As a controls engineer who spent many years wiring I like to think of the robot as a training ground. As you can see from this thread there are many things to know and tricks that help. I usually do a lot of talking while the students are wiring, hopefully helping them learn.

We plan ahead using AutoCAD Electrical to make a full schematic in the style most used by automation manufacturers and label our wires according to the line they are found on the schematic, and try to make sure the people wiring understand what all components are doing.

Here is our schematic from 2010 (if the link works):

http://www.chiefdelphi.com/media/papers/2384

[cadandcookies]

I just wanted to say that this thread was a great help to and inspiration to 2220's electrical team in the 2014 season. Our electrical team took many of the ideas and principles from this thread and turned out the best and neatest wiring the team has ever had, which not only helped with maintenance, but also allowed us to pursue a better integrated design that wouldn't have been possible if we'd used our previous spaghetti wiring practices.