One of the projects that we are doing in the Pre-Season, is to make our electric wiring neater and more organised. Last year was our second and because we used 6 motors(4 for the gearbox, 2 for the arm & hook) and 8 spikes the wiring looked very tangled. Althought we had the wiring out of the way it didnt look very nice, it was hard to access and hard to identify. Also the 3-pin wires from the controllers were labeled, but still when they were all zip-tied together it was very hard to replace or change a wire(all our wires were labeled). Other than organising we crimp,solder and heat shrink our connectors and make sure that our electrical is safe.
So my request to all the great teams here is that please let me know about different toold & products you might use to make ur electrical neater(wire clips, snap-on connectors,labeling products e.t.c)
For the time I’ve been on my team, we never really had neat and organized wires. During 2004 we attempted to nicely sort out the wires, but later we ripped all the organized wires while hastily trying to repair our drivetrain…
but anyways, I remember seeing 968’s robot with their very neat wiring: http://www.chiefdelphi.com/forums/pictures.php?&action=single&picid=6476
Use 12 gauge wiring liberally. The 12 gauge wire is very easy to keep track of, is very flexible, gives you excellent current characteristics, and is rather forgiving of bends/kinks.
Use “relay farms”. A relay farm is a piece of plexiglass with holes drilled out for up to six relays each. Then six relays are mounted. Use one on each side of the robot. This way, you have spare relays on board (we usually have 1 spare per farm) and can remove all the relays on a side at once.
Do the same as above for Speed controllers. However do not keep spare speed controllers on the robot - they are too easily damaged there - but have holes drilled out for them.
Use color-coded stickes on each wire pair (+ and -) for a device. NOTE DOWN WHAT COLORS ARE CONNECTED TO WHAT DEVICE! DO NOT LOSE THAT PIECE OF PAPER! (I speak from experience; I have lost wire-color maps twice, they are a pain to reconstruct)
Crimp the ends of connectors very very well. Then solder them. You can never have a strong enough joint.
Do not ziptie wires together in a bundle unless you have a very good reason to do so. In general, do not overuse zipties. Use velcro loops instead, as they are far more easily removed.
Make sure the battery connector is easily accessible. You never know how quickly you will have to change it.
Have a diagram of all the wiring on the robot. This diagram should, preferrably, be locatable at critical times during build season and in the pits.
I didn’t have a pic of our final wiring but what we did was channel all of our wires. The direct route is not always the neatest. Take your time, plan ahead and pretend that it is art. If you do, not only will it be neat but easier to follow. If you would like to come visit us let me know.
If you haven’t done so check out the picture Steve links to above. In addition to starting out very neat, all of the power devices are fairly close together. This keep wire runs short (more power to the motors) and has less weight than spreading them all over. (Steve, I may like to use your photo as demo example. Would that be OK?)
Venkatesh, I think you mean #10, that is the minimum wire size for most of the motors and power to speed controllers. #10 Zip cord, colored red and black, is available in spools from Newark. It is fairly flexible, easily routed through mechanical stuff and quick to terminate. Follow Venkatesh’s advice for soldering all crimped connectors. I know it sounds like suspenders and a belt but you can’t play if you don’t work.
Color coding is easy with 3m EIA colored tape, available from Digikey. This comes in rolls of ten colors, I think 3-5 yards of each. We wrap each wire from power distro to speed controller, from speed controller to motor, PWM cable, circuit breaker and CB location. position on RC and spike or victor. With one glance you can see which PWM cable on which RC output feeds which speed control or spike which in turn feeds which motor and know which circuit breaker to pull to disable the circuit or which one to put back when you have removed them for troubleshooting.
Use finely stranded wire so you can get nice contours and bends. In particular, I’ve always thought that the 6 gauge wire provided in the kit is absolutely aweful because it is not finely stranded at all and is very stiff. Spend the money to get some nicer wire (less resistance too)
Also, those sticky backed zip tie “mounts” will come in handy for securing wires.
Last, wire wrap of some sort often (available at auto parts store or maybe hardware store) does a nice job of tidying up things and works great in a situation like a flexible joint of an arm. The stuff is black plastic tube with a slit down one side.
Some good guidelines here, but I have a few questions for you guru’s:
Why do you say to use velcro instead of zipties? Seems to me there would be less stress on the wire bundle to just snip off a ziptie than there would be to try and rip the velcro.
What brands of super-flexible wire are you using? (I know Paul Copioli and 217 have used this stuff on their well-organized wiring jobs - they are my benchmark for great wiring).
Aren’t you supposed to solder the end BEFORE crimping? This is called tinning I believe.
One idea that we have used the last few years: rather than hard mount the polycarbonate control-mounting-board to the robot, we have “suspended” it trampoline style from the frame. Seems to me that this is lighter and it provides some amount of isolation from the vibration of the robot.
No! You should never tin wires before crimping because you won’t get good pressure distribution inside the crimp and it will loosen over time. If you use good quality crimp connectors, sized exactly for the wire gauge, crimped with the right tooling, the connection will be as good as it gets (without soldering). Because there are so many “ifs” in that, soldering after crimping is recommended for most other cases!
When I saw the title of this thread the last thing I expected was for one of my robots to be mentioned, much less alongside the likes of the mighty Travis Covington’s superior wiring techniques. Thankfully John was just brining up a little trick we used that year, and other teams have done as well. Seriously, Travis’ wiring always drops my jaw. It’s something that we all should aspire to wire like.
There are several companies that make velcro just for wire management. I think it is OK for static loads but I question it’s use on movable objects like our robots. The load on a large wire bundle during a hit is likely to open.
Newark sells a #10 zip cord that is not super flex but is more flexible than most off the shelf #10. It is designed for automotive stereo install and has a red and black wire.
A great connection is one that is mechanically stable first. Any connection that will be soldered should be crimped tight first. We use a equivalent to the Anderson connector for #10 connections (to make it easy to change) to motors. We add push on 1/4" connectors for speed controllers. (The same as are on the circuit breaker panels.) All of these connectors start out as uninsulated. We crimp the wire then solder and add a piece of heatshrink over the wire and connector to protect it, the contacts for the Andersons must not have exposed wire after contact insertion. Never “tin” wires before a crimp contact as explained above.
Adding a poly plate to mount everything just adds too much weight for us. I am under STRICT guidelines for weight restrictions. (wink, wink)
I really can’t talk too much (our robot’s wiring job was TERRIBLE!!!) but here’s some good ideas.
Use plugs. If you use, say, a Molex connector, then if you have to pull a component or even an entire board, you just disconnect it. My team is after me to modularize the entire electronics board, so this seems like a reasonable idea. It is, however, one more thing to go wrong.
SOLDER WHENEVER POSSIBLE!!! I really don’t care if you have crimp fetishes or only have crimps or if you have already crimped a wire. Crimps fail much more often than solder jobs. (Last year for our main connector to the battery, we used crimps tightened down in a vice, then we heated it with a blowtorch and put lots of solder on it. Worked like a charm, and looked cool too.)
Never, and I mean never, put a wire under stress and expect it not to come out. If you have a 12" gap and an 11" wire, then go get yourself a 13" wire, dangit! Vibrations can wear through wires, pinch sections can cut wires, and tension can pull your connectors right out. USE A LONGER WIRE THAN WHAT SEEMS REASONABLE! it may weigh more, but it will work.
Neatness and orgainization is a very valuable thing to have on a robot. It streamlines repairs, diagnostics, and makes the robot look good. And your team will love you for it.
1.The Velcro/Zpties debate has went around quite a bit in the manufacturing environment for the plants. We used to see tons of zip ties on the robot and tool dress, some of them waaaay to tight causing a failure point. We then moved on to rubber straps that had some give and were reusable. However we found that people put them on way to tight just like the zip ties and the rubber broke down VERY fast and failed. So the current method is both, but take care not to pull with all your might which can cut into the insulation on the wires, I like things to be ‘snug’
I agree that soldering is a solution to prevent failed connections. I do want to say that there is a way to add too much solder when making connections. Stranded wire will wick solder (just like water soaks into a paper towel) and that extra will end up far from the joint. For most applications this is not a problem, but this wire now becomes very stiff, almost like solid wire. A solid wire on a moving object has a greater tendency to fracture after repeated movement. When soldering connectors (to the 1/4" push on crimp type, for example) heat the connector until solder flows when applied to both the wire and the connector. Add just enough solder for it to be just visible flowing under the wire insulation. After the joint cools, the wire should still be flexible almost to the end of the wire. This is especially important for connections to the controllers, battery and FP motors. A stiff wire will transmit movement into the terminals and cause internal damage over time.
Don’t forget adequate insulation over the soldered joint, heatshrink works better than tape and more fun to use.
I agree with you there. I have often had only tape around, and used it, then regretted it. It sticks to whatever you are using to get it off, leaving a sticky black residue, and it’s not easy to get a good grip on and unwind. Heatshrink, because it’s not sticky, doesn’t have these problems, but be sure you heat the heatshrink slowly and evenly. I have a friend that simply stuck it on a soldering iron, and it melted right through the heatshrink (counterproductive, if you ask me.) Just remember to cut it and put it pretty far down the wire before you solder the connection, as you won’t have a chance later.
My 2 cents.
I don’t know very much about wiring. I wasn’t really involved with the electronics on the robot last year…I wasn’t really involved with the robot for that matter, but I am interested now that I’m taking an electronics course and am doing my very own wiring. I know someone else has probably already said this, but I saw it on our robot, and I think it helped a lot: PUT LABELS ON EVERYTHING. Just little sticker labels on the wires themselves and the places where they go. You can do color coding, numbering, names, etc.
That’s about all the advice I can give, and again, I bet you already knew this. But I hope I was of some help if you didn’t.
I am not sure what product you are referring to as “cold shrink”.
I use a variety of products depending on the application. Heatshrink is the easiest to cut, shape, etc. and makes a nice finish look. When the need arises for a repair justs take a sharp blade and cut down the length of the covering. If you need a higher voltage breakdown just add a second or third piece over the top. It is not waterproof, though, even the meltable interiors tend to leak a little when out in the weather. There is a good product called COAXSEAL, available from many locations including Radio Shack. It makes a good waterproof, ultraviolet resistive, flexible seal but is nasty stuff to work with.
Since waterproof is not a requirement for our robots, yet, heatshrink is easy for everyone to use and electrical tape a close second.