View Full Version : How to wire unrealistically well?
Hey all,
We're pretty fed up with how horrible our wiring has been in the past two years- simply not neat, not streamlined, not anything.
We would really like some tips and pointers about how to wire extremely neatly and streamline our wiring, I'm looking for something along the lines of:
https://www.dropbox.com/s/rqnwpjmhjkrs4ii/968%20RAWC%2009%20chassis.jpg
http://www.greybots.com/uploads/1/4/6/6/1466639/1060584221_orig.jpg
Believe it or not, there aren't really many tips to do that. The main thing is time. Wiring takes lots of it, so make sure you have enough. Second, it helps to plan ahead where components and wires will go. Finally, use tons of zipties and fasteners.
ehfeinberg
17-12-2013, 20:27
One of the easiest ways to get neat and clean wiring with limited effort and experience would be to use wire ducts (http://www.mcmaster.com/#standard-wire-duct/=puqx40). A few well placed wire ducts on your electronics board can easily manage wiring with little extra work.
449 used this last year, and we would recommend it to all teams who don't necessarily have the resources to create 968/1538 style wiring.
saikiranra
17-12-2013, 20:29
Secret: A metric ton of zip ties, zip tie mounts, and time.
Wire only stays so neat when it has a place to be, and zip ties are perfect for that. Bundle wire going to the same place (for example, PWMs from the DS to the motor controllers or power wires from the PDB to motor controllers) in a neat fashion, meaning line each wire with the same color facing each direction, and zip tie the wires together every few inches.
Keep everything standard. Use the same zip tie colors, crimp connectors, and wire. It looks better.
Actually, thinking about it, thats really it. Just set out to wire well and you will wire well. If it looks pretty, you are good.
I actually don't have any pictures on hand of the wiring on our robot, but this (https://s3.amazonaws.com/ksr/projects/427127/posts/408691/image-213629-full.jpg?1361218722) was us a few nights before bag date last year.
colin340
17-12-2013, 20:47
keep your eyes peel team 340 is going to be shooting a video about a cool 3d printed part that has helped a ton
AdamHeard
17-12-2013, 21:02
We may make a video on our wiring process, gotta convince all the wire monkies to do it first though.
Blueamber
17-12-2013, 21:03
Our team color codes our wires so its easier to trace/ replace if need be.
connor.worley
17-12-2013, 21:13
- An aluminium bellypan is pretty much required for our style of wiring, but a polycarb base with holes drilled out for zipties can also be used. You'll probably end up with some accidental holes and it won't be very pretty, but it's a good start towards cleaner wiring that's easy to maintain. We used white polycarb for this in 2011. Clear might look cool. YMMV.
- Use lots of zipties. Properly trim them, place at regular intervals along wire runs, etc.
- Use heat-shrink tubing over crimps and splices.
- When laying out runs, give yourself a few extra inches of wire when you cut. Connectorize one end, lay it out, then cut the other end to length & connectorize.
- Use zip cord (nonglossy looks better).
- Give yourself enough wire for strain relief.
- Color coding is, in our opinion, not required. Our philosophy is that the wiring should be clean enough to easily trace without any extra markings.
Here are a couple of examples of our wiring 2012 (http://www.chiefdelphi.com/media/img/84d/84d3afa859844fc1a6db221e579aeb7a_l.jpg) 2013 (http://www.chiefdelphi.com/media/img/6f0/6f0bdce7a8eda83cf8fe8693114707a5_l.jpg)
^Connor is just bragging with those pics :P
Totally love the wiring job.
I'm just wondering, but wouldn't that cRIO placement be illegal? Doesn't the cRIO ground itself? Is that a metal matrix under the electrical components.
If you're trying to clean up, why don't you just copy the team's wiring in the model, and tweak it so it fits your needs? An engineer steals one's idea and makes it better!
connor.worley
17-12-2013, 22:04
I'm just wondering, but wouldn't that cRIO placement be illegal? Doesn't the cRIO ground itself? Is that a metal matrix under the electrical components.
If you're trying to clean up, why don't you just copy the team's wiring in the model, and tweak it so it fits your needs? An engineer steals one's idea and makes it better!
There is a rubber adhesive sheet underneath.
MichaelBick
17-12-2013, 22:15
I'm just wondering, but wouldn't that cRIO placement be illegal? Doesn't the cRIO ground itself? Is that a metal matrix under the electrical components.
If you're trying to clean up, why don't you just copy the team's wiring in the model, and tweak it so it fits your needs? An engineer steals one's idea and makes it better!
Because the types of electronics, amounts, and needed routes tend to change every year. For example, this year the reduced robot sizes caused it to be a lot harder to fit in all the required electronics.
BrendanB
17-12-2013, 22:25
Something that hasn't been mentioned so far is time. You need to give your electrical time with the robot to get their job done properly. Unfortunately for us time is never on our side so a majority of our robots have been wired in a few meetings or on practice days.
Hey stuff happens! ;)
MrForbes
17-12-2013, 22:34
We would really like some tips and pointers about how to wire extremely neatly and streamline our wiring, I'm looking for something along the lines of:
https://www.dropbox.com/s/rqnwpjmhjkrs4ii/968%20RAWC%2009%20chassis.jpg
http://www.greybots.com/uploads/1/4/6/6/1466639/1060584221_orig.jpg
In the two pictures you provided, the robots are not completed, so we don't see all the sensor and control wires...only the main power wires. It's when you add the next few layers of stuff, that things tend to get messy.
Like everyone says, planning and taking your time are the keys to neat wiring.
DampRobot
17-12-2013, 22:46
I've heard that EJ from 254 likes to rip out the wiring his kids have done overnight if he doesn't think it's neat enough, just to make them do it again. This really gets great results. You can also employ the RC method of making students do pushups if they don't do quality work. Discipline is a very necessary part of making a neat electronics board! If kids get complacent, they tend to stop aligning the power wires together, making sure that the speed controllers are evenly spaced, and even "just plugging in" the PWM cables without zip-tying them down.
As I always say: beatings will continue until morale improves!
I am generally really picky when it comes to wiring. The biggest thing I notice when it comes to wiring is make sure you dedicate space to the electronics. Often, the electronics are placed where they fit and not properly assigned a spot. Another thing that makes electronics messy is constantly fiddling with them. Moving them for other components, adding more electronics as parts are added and so on. When setting up an electronics board think about how the wires are going to run while setting up the layout. Wire way can be a nice addition to an electronics board as well as wire wrap for bundles of cable. As pretty much everyone has said, Zip Ties. Make sure to use them properly. If you are adding wire to an existing bundle of cable, cut the old zip ties as you add the new ones. It can make it look a LOT better. Labeling can help when there are connection that may appear as though they could go to multiple places (Side Car). Most often I don't see a need to label power because if cut to the proper length it is easy to see where they should go. Wire can also go in places that may otherwise be wasted (inside square tubing, tied inside C-channel and other enclosed areas that are safe) .One thing that can help is practice. The more electronics boards you build the more you will find ways to make them look better.
Nathan Streeter
17-12-2013, 23:31
Here are a couple of examples of our wiring 2012 (http://www.chiefdelphi.com/media/img/84d/84d3afa859844fc1a6db221e579aeb7a_l.jpg) 2013 (http://www.chiefdelphi.com/media/img/6f0/6f0bdce7a8eda83cf8fe8693114707a5_l.jpg)
In these photos it looks like for most of the length of the PDB <-> Victor power wires, both are black... did you heat shrink wire pairs along most of their length?
In many ways that seems like a great idea... it just uses a lot of heat shrink tubing!
DampRobot
17-12-2013, 23:33
In these photos it looks like for most of the length of the PDB <-> Victor power wires, both are black... did you heat shrink wire pairs along most of their length?
In many ways that seems like a great idea... it just uses a lot of heat shrink tubing!
Nope, they just align all their wire so the red is all on the bottom and the black is all on the top. The wire comes with the two strands grouped together, which makes wireing generally easier.
BrendanB
17-12-2013, 23:42
In these photos it looks like for most of the length of the PDB <-> Victor power wires, both are black... did you heat shrink wire pairs along most of their length?
In many ways that seems like a great idea... it just uses a lot of heat shrink tubing!
As DampRobot said its wire that comes connected together and the top wire is black and red on the bottom.
We use the same stuff on our robot this year from McMaster (9697T3 and 9697T4) for both 14 and 12 gauge wire. It was great stuff as it stays together making wiring easier and pulls apart with no effort when you need to put connectors on the ends.
artdutra04
17-12-2013, 23:49
There is one secret to making wiring look neat like the two examples above, and that is to severely constrain yourself to where you can place wires.
Think of wires like cars. You can only drive your car along roads - if you take a shortcut through someone else's property they will get mad. In cites such as New York City, roads arranged in a square/rectangular grid pattern make it easy to navigate. To make your wiring look neat and easy to work on, we will follow this same virtual "road" grid pattern.
This means your wiring should only travel in straight orthogonal directions, and always make clean right angle corners*. To make corners that look good, use a very high strand count wire - in general the more strands a wire has, the more flexible it will be. The more flexible wire is, the easier it is to tame and make it travel along these "roads".
This will cause large sections of your wiring to all begin running along the same path - think of these like your trunk line "highways". Sometimes this means wires intentionally take longer paths than necessary to keep these wires on dedicated "roads", like visible in this photo of FRC 973:
http://www.greybots.com/uploads/1/4/6/6/1466639/1060584221_orig.jpg
But this solution only deals with the power wires - you still need to deal with the signal/PWM/sensor wires. Keeping with the same city analogy, we need to treat these as a subway or monorail and route them on a different level from the cars on the main level.
While running wires underneath a control panel might not always be feasible (especially if it is your belly pan), one idea that works really well is to build pylons using a small (#8/32 or smaller) standoff with male thread (http://www.mcmaster.com/#92745A550) at the top, which is screwed into small (#8/32 or smaller set screw) shaft collars. The shaft collars act as a anchor point for a small 4" zip tie, and the standoffs elevate this above the rest of your wiring. You can then bundle all your PWM/sensor wiring along this trunk line.
I don't have a good photo of this from one of 148's recent robots, so here's a quick sketch instead:
http://www.chiefdelphi.com/forums/attachment.php?attachmentid=15573&stc=1&d=1387341624
* IMPORTANT! Do not make these corners too tight, or you will strain your wire and cause increased electrical resistance. Due to V=IR causing a voltage drop, this means your motors will always receive less voltage.
If you really want unrealistic wiring, the method I have always thought of is a very large circuit board, with all of the wiring embedded in the wafer. This probably breaks several rules, as well as requiring a belly pan, which adds to the already high weight you would encounter with a PCB this size. Another problem would include the time required to print the board and much less capability of switching designs.
Something like this,
15574
This was from our summer build. It's just a matter of routing the wires neatly, and we don't like crimp connections, prefer to solder instead.
Think of wires like cars. You can only drive your car along roads - if you take a shortcut through someone else's property they will get mad. In cites such as New York City, roads arranged in a square/rectangular grid pattern make it easy to navigate. To make your wiring look neat and easy to work on, we will follow this same virtual "road" grid pattern.
This means your wiring should only travel in straight orthogonal directions, and always make clean right angle corners*. To make corners that look good, use a very high strand count wire - in general the more strands a wire has, the more flexible it will be. The more flexible wire is, the easier it is to tame and make it travel along these "roads".
This will cause large sections of your wiring to all begin running along the same path - think of these like your trunk line "highways". Sometimes this means wires intentionally take longer paths than necessary to keep these wires on dedicated "roads", like visible in this photo of FRC 973:
But this solution only deals with the power wires - you still need to deal with the signal/PWM/sensor wires. Keeping with the same city analogy, we need to treat these as a subway or monorail and route them on a different level from the cars on the main level.
While running wires underneath a control panel might not always be feasible (especially if it is your belly pan), one idea that works really well is to build pylons using a small (#8/32 or smaller)
Our team also wired the electronics board like elevated highways. We used standoff and P clamps. To save space, we actually screwed the standoffs on top of the Jaguar's mounting holes doubled as the screws securing them. The outside mounting holes hosted the "power" highway and the inner mounting holes hosted the "signal" highway.
Al Skierkiewicz
18-12-2013, 07:34
Hey, I will be the first one to point out wiring as shown as being pretty cool but...
I am more for getting as much current to the motors as possible and that means short straight runs. Every sharp corner and common path adds inches to the wiring which translates to losses. Simply positioning the controllers near the PD on both sides minimizes the loss. Remember the series resistance is in both the red and the black wiring. One wire foot (1' of #10, 2' of #6, 6" of #12) will drop 0.1 volts at 100 amps. A two foot run is four wire feet.
I think it is best to have a very small electrical team that actually gets work done, because they can communicate much easier. We have two members, Ryan and Ben, who actually get work done while everyone else is messing around!
In short, keep the electrical team short and make sure that they are always working on something! Their ain't any end to improvement ;).
drwisley
18-12-2013, 08:11
In addition to the previous great posts, constrain the wires between components in the nice paths, with clean turns, prior to connecting on either end. Leave 3-5 inches of wire on each end. Once all the runs are complete between the components, then cut, strip, crimp and or connect. If you want beautiful wiring, you will waste tons of wire until you become proficient. I really like Art's post.
One last thing that hasn't been said, but possibly implied. Many times if you aren't building a prototype (second bot), if you want a clean wiring of your bot, you'll have to make the initial runs a bit long and messy, then go back and clean them up. Many times I've wired long messy runs, to test and get it working, only to go back and run the wires neatly and cut to length (new connector). You have to make sure if you plan on doing this, you include the extra time it will take to make these corrections/cleanings. Many teams when prototyping will work on the placement of the components on a bot. When building their compitition bot, already know where everything is going and build their electronics board away from the drivetrain and minipulators only to bring it in and make the final connections. (trim wires to length and connect)
It takes Time (lots of it) and Planning. Sometimes more time planning then actual time doing the wiring.
Like has been mentioned, practice with controller boards in the off season to get more time and experience.
sanddrag
18-12-2013, 08:23
In the two pictures you provided, the robots are not completed, so we don't see all the sensor and control wires...only the main power wires. It's when you add the next few layers of stuff, that things tend to get messy.1538 would disagree. (http://kiet.us/1538/robot_PWM.JPG)
I think a big piece of clean wiring is having enough space for the components. The example pictures are from 254, 968, 973, and 1538: all West Coast Drive teams. WCD has its outer rails as far as possible to the outside, so the middle area for electronics is as big as it can be. It's also possible to get that much space using sheet aluminum chassis. Making wiring look that clean with a C-Base chassis is much more difficult because there's way less space between the rails. We've used C-base in the past three years, and we've had to build a second level for electronics in each case. Having two levels adds some additional challenges for getting the wiring to be organized and nice looking. That was especially true last year with the reduced maximum robot perimeter; the perimeter got smaller, but the power board / CIM motors / cRio / battery / etc still took up the same amount of space on the drive base. Doesn't leave much room for motor controllers.
I just looked up some pictures of our wiring - wow, wires are running in every direction. I'll have to make sure our wiring people read Art's advice before we let them wire anything this year. I can think of a couple of egregiously long wires/cables in particular that irritated the crap of me last year, and people ignored me when I told them to fix it... this year those are getting torn out overnight. Thanks for the pro tip, CD!
MrForbes
18-12-2013, 10:30
1538 would disagree. (http://kiet.us/1538/robot_PWM.JPG)
Would disagree with what?
I'm talking about normal, messy wired robots....ours look great until we actually get enough wires on them to get them working, then they become a mess.
But I guess this thread is all about unrealistic robots, so it doesn't matter
DonRotolo
18-12-2013, 11:58
keep these wires on dedicated "roads", like visible in this photo of FRC 973:Also carefully notice that there is a small "service loop" of wire at the connection (particularly at the PDB) that gives a little slack to allow the wire to be disconnected abd reconnected if necessary. Don't leave wiring so tight it can't be moved.
I think it is best to have a very small electrical team that actually gets work done, because they can communicate much easier. We have two members, Ryan and Ben, who actually get work done while everyone else is messing around!
In short, keep the electrical team short and make sure that they are always working on something! Their ain't any end to improvement ;).OK, we have one kid who is over 6 feet tall - should we get rid of him? He's pretty good at it and we'd hate to lose him...
So these pictures of nicely routed wires are missing a key item.
Cable labels. It's nice for you that wire a robot once and then never need to remove components, unfasten wires, etc.
Cable labels can save the day! I've used the lables that roll around the cable, they come 0-9 and A-Z.
In a more perfect world cables get double labled
]] this end / the other end ------------------------- the othe end / this end [[
(Art has sketching skills, I don't )
This allows you to take the device off and know where the now dangling end goes, or lets you do a traceback through that nice neat bundle of ziptied cables go.
Also carefully notice that there is a small "service loop" of wire at the connection (particularly at the PDB) that gives a little slack to allow the wire to be disconnected abd reconnected if necessary. Don't leave wiring so tight it can't be moved.
OK, we have one kid who is over 6 feet tall - should we get rid of him? He's pretty good at it and we'd hate to lose him...
No. What I'm saying is to keep the team short. Don't get rid of anyone! As long as everyone can effectively communicate with each other, the team is the right size!
Luke Harma
18-12-2013, 18:06
Zip tie and label your wires.
Maybe you could try using software to show a picture of what you would want your wiring to look like before people start wiring it. If people know what it is supposed to look like before they start it might help out. For example, SolidWorks Electrical will allow you to wire components along a 3D sketch or guide line in the CAD model. Then you can flatten this and find out exactly how long each wire needs to be so it can be cut to length beforehand. You can also use the software to check for clearances and interference so you know if you have enough space for all the wires before you start.
Jon Jack
02-01-2014, 17:10
I'm just wondering, but wouldn't that cRIO placement be illegal? Doesn't the cRIO ground itself? Is that a metal matrix under the electrical components.
We use an adhesive backed silicone sheet (McMaster P/N: 8622K41). We cut the sheet to the size of the cRIO and stick it on. You can do this to several cRIOs with one $38 sheet.
Another thing we do is use nylon fasteners. We do this for a few reasons:
Using plastic fasteners on the cRIO helps further isolate it from the baseplate.
You can trim all the fasteners to length (after they've been installed) with a pair of flush cutters.
We're tapping into 1/8" thick aluminum and the threads on the nylon screw will give before we can strip out the tapped hole in the baseplate.
They're light.
Don't forget that copper is heavy. The weight of #12 or #14 wire is not insignificant.
All that neat, right angle turn wiring looks nice, but the hypotenuse of a triangle is shorter than the two sides.
We had a panel with a number of victors one year and wired it all neat and tidy, with a loop so that the panel could be swung down to work on. We needed to lose some weight, though, and ended up cutting about half a pound out of it all without much trouble by re-routing many of the wires.
Layout is important. If the flow from the battery to the main breaker to the PDB to the motor controllers is short, things will be much easier.
Audrey Chu
05-01-2014, 17:52
Last year our team was more successful than we've ever been electrically. We had a two person team. Everyone has his or her own style, but the main things were patience and a perfectionist streak. I think I rewired the robot (meaning stripped it down and rerouted wires) maybe five or six times during the last two weeks. I would suggest that you keep in mind where you want your wires to be or not be throughout your design process and maybe even use markers while prototyping.
We use an adhesive backed silicone sheet (McMaster P/N: 8622K41). We cut the sheet to the size of the cRIO and stick it on. You can do this to several cRIOs with one $38 sheet.
Another thing we do is use nylon fasteners. We do this for a few reasons:
Using plastic fasteners on the cRIO helps further isolate it from the baseplate.
You can trim all the fasteners to length (after they've been installed) with a pair of flush cutters.
We're tapping into 1/8" thick aluminum and the threads on the nylon screw will give before we can strip out the tapped hole in the baseplate.
They're light.
Haha Ya. We screw the cRIO into the wood, but velcro everything else!
My team's wiring was always immaculate, largely because one of our mentors took the time to make a full size drawing of exactly how he wanted the motor controllers/CRIO/power distro board placed. After that, he would show me exactly what path the wires should take to get where they needed to go, and as long as I followed that path and remained disciplined, all was good.
The biggest thing for me was having a plan and then executing it with as little interruption as possible.
Ariane Nazemi
06-01-2014, 02:48
For some strange reason I believe robot wiring should be in an odd space between zen art-form and OCD organization. I always relish the opportunity to bring order to the chaos of wires that need to criss-cross throughout the robot. Making them look beautiful in the process is an added bonus. If you consider the wiring itself to be a kind of art project, it makes things that much more enjoyable (for me at least). I really look forward to seeing what my team can do this year, being rookies I hope we can learn clean and beautiful wiring technique at an early age.
Also this is my first official post on Chief Delphi, so I just wanted to say hi!
Cable labels. It's nice for you that wire a robot once and then never need to remove components, unfasten wires, etc.
Cable labels can save the day! I've used the lables that roll around the cable, they come 0-9 and A-Z.
This is a link to the cloth labels 2363 uses. They are easier to wrap around the wire and stay unlike labels from a label maker(they fall off in a day).
http://www.mcmaster.com/#standard-wire-labels/=sl7zlz
We use the wrap-around wire markers with NEMA colors (blank) and then write the number or voltage needed for the wire.
Also, one of the keys to good wiring is the right material to mount the electronics on. The other pictures show an aluminum bellypan with large spaces in it for ease of using zipties. We ended up using a perforated polycarbonate from AndyMark.
http://www.andymark.com/product-p/am-0836.htm
And of course no wiring job is complete without 1000+ zipties.
iKiel2012
21-07-2014, 15:44
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...
Chris is me
21-07-2014, 20:23
We've been gradually getting better at wiring over time. We'll never be the Poofs, but we've got functional and organized wiring.
This was mentioned already, but one really easy trick that helps a ton is to use zip cord. Red-black zip cord in FRC wire gauges is commonly available and really helps keep things together. Even if you do nothing else, zip cord should cut your wire mess in half.
We've used wire ducting before to get wire runs out of sight, which is neat enough for a lot of teams. You can get wire ducting in the same sizes as rectangular tubing which I think makes the wiring more aesthetically pleasing.
A new thing we used everywhere this year was adhesive backed zip tie mounts. Similar to McMaster part number 7566K64, these little things allow you to put a zip tie wherever you'd like on a wire run without having to drill holes. Since we've rearranged our electronics layout more than a few times, using these instead of holes helps prevent a belly pan that looks like ugly swiss cheese.
221Sarahborg
21-07-2014, 21:00
Make sure to plan ahead in wiring as far as layout goes. We usually get to know what all we need to wire to and where our limits are so we get to work with all of our components on our base board knowing where they would best fit. We also make a digital schematic with all of the parts showing wire connections to what and where they go to. Make sure you keep in mind where mechanical or pneumatic stuff needs to go.
As far as keeping it organized on there, we use wire spiral wrap (http://www.foreandaftmarine.com/639-452251A.jpg) to keep groups of wires together or the wire ducting/highways. You can use zip ties for situations you might need as well, such as if you have one going a long way around your robot.
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
21-07-2014, 21:53
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
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
22-07-2014, 09:55
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
22-07-2014, 10:48
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
22-07-2014, 13:55
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
22-07-2014, 14:13
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.
http://www.nixiebunny.com/4183wiring.jpg
evanperryg
22-07-2014, 17:19
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
22-07-2014, 21:42
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
23-07-2014, 17:06
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.
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/hydraulic-wire-crimping-tool-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
24-07-2014, 09:32
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/hydraulic-wire-crimping-tool-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
15-09-2014, 17:09
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.
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
15-09-2014, 23:52
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.
BrendanB
16-09-2014, 08:58
Our team worked much harder this year on making our wiring neater and it was well worth it! During week 6 we were able to set aside two meetings for our electrical team to have alone time with the competition base while the mechanical teams worked on the practice robot and competition assemblies. We also took the time during the design stage to come up with a plan for mounting the electronics and had them in our CAD model so we knew they fit.
The general power and signal wires were all neatly tucked away in wire duct and it was the first year we didn't have crimp connector or pwm fail which I can only believe was because our messy wiring in the past left them loose and exposed.
If you look at our robot now it doesn't look very neat because the top layer is the pnuematics that were thrown on the robot at the last second but underneath is a beautiful board. Next year's plan is to focus on making the electrical and pnumatics neater.
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