We use PWM extension cables for motors on manipulators that get moved around quite a bit. We’ve found that the cables have a tendency to come unplugged (not enough friction), and we’ve been using scotch or masking tape to keep them together, which is illegal. We’ve tried anchoring the cables down using zipties, which are clumsy and not as effective as tape. Does anyone have a better solution that’s FVC legal? The cables are long enough, with no tension (except gravity) on them.
Hot Glue gun. One glue spot on the place the PWM plugs into the housing works. Both sides if you want to really hold it down.
This is an FVC thread, not an FRC, and glue is not legal in the 2006/7 FIRST Vex Challenge.
The best solution I have seen is just being mindful of where your wiring runs are, and placing the cables and connectors in places they shouldn’t be pulled apart.
You can also loosely knot the connection.
In the past we slightly seperate the wires from one another at the connector and then use a small zip tie to keep both ends connected.
In the future we plan to make our own custom lengths to fit as needed to avoid that situation.
I thought that wasn’t allowed for the Vex competition?
I thought it had to be a standard off-the-shelf vex part to qualify.
Whoops!!! Sorry about that confusion. I should pay more attention to what forum something is in before I post next time. :eek:
As far as an effective solution, it would work and maybe FVC will relax that rule as a solution next year if you give them feedback relating to the problem and the solution I suggested.
Sorry again for the confusion! :o
Currently, the only FVC legal way to keep pwm extension cables together is to zip tie the each side of the connector to some part of the robot. Even splitting the pwm cable to slip a zip tie through, is modifying an electrical component which is not allowed under the FVC rules. Also, custom built or custom length pwm cables is NOT legal for FVC.
I have asked IFI to create a FVC legal product which would function similar to one I found, and use for FRC, made by Maxx Products - a Universal Security Clip. It is being considered and, hopefully, it will be available for next year. If you think its a good idea, you might want to drop IFI or the GDC a post asking to make these FVC legal.
If you’d like to try these clips for FRC here’s the link:
Look about half way down the page for the Universal Security Clip.
I hate when pwm cables get unplugged. Happened to us during a competition, and we lost a match because of it…
anyways, the best way is probably zip tie both sides of the pwm cables tightly, so only the middle stretches/compresses because of your robot’s manipulator moving.
This rule makes no sense. I don’t know why taping the pmw connections together should be illegal. No one wants to win because the other team’s robots pwm cables came apart. I hope they give this rule a good hard look, and either change it or create a product as skimoose suggested
we used eletrical tape which we still had a couple problems with but we found if you can get the close to a stationary object or at least stays straight like a piece of metal zip tie both side down tight. that seemed to work for us but only because we had something to zip tie to. I also agree losing a match because a PWM slips out is not fun it happened to us in the semis at a scrimmage and then in the finals at the socal CSUN competition.
I’m not sure if it would work, but try placing a strip of non slip mat over the cables and fasten it down on both ends, the holes int he mat should expand enough for the cables to go in, but should close enough to keep the cables in.
I’ve never tried that, but it could work, otherwise zip ties are the only vex legal way to go unfortinately
The rule comes from the FRC side. Electrical tape can only be used as an insulator. No tape, of any kind, can be used to join components together.
Engineering doesn’t involve duct tape.
the idea that skimoose suggested is similar to tied the cable down to a stationary part with two zip-ties at both end. this rule make us think of a way around it. :D. but using tape seem convenient, too.
I think Mark had the best soultion, tie the junction in a simple overhand knot and use a trywrap to hold the whole thing together.