In general, if your electrical design adds connectors these become
additional places where connections can be bad. We cut our PWM
cables to length, keeping the original male plug for the victor or
spike, replacing the female connector with a molex c-grid connector
using proper crimp tooling and careful inspection of the terminals
prior to assembly.
The cable is zip tied down to the mounting board near the victor or
spike and near the controller. The wire goes up-and-over into the
victor, spike, or RC, providing good stress relief.
We cut the female end because the original male end of the PWM
cable is required to get good retention in the spike or victor. Additionally,
one can glue the c-grid connectors together as you install them on the
RC, producing a single connector that is very difficult to have wiggle
its way off. We do this for our array of switches used to select
robot behaviors as they tend to work loose otherwise.
The TTL card is very problematic. You can solder it onto the pins
of the RC using a high quality soldering iron with a very fine tip,
or you can make a bracket to retain it. We made a bracket to retain
ours and had no problems with it working its way off at PNW. The PWM
cable on the TTL card stays on quite well, but it is again very important
to zip tie the cable down with a little stress relief so it can't pull the
connector loose from the TTL card.
The two pwm cables that plug into the camera are very problematic.
We removed the sockets from the board and soldered cables directly
to the board. We also glued the camera to the board using epoxy
and some small wood blocks. The de-soldering job is very tricky as
the board has plated through holes, but it is worth doing in order to
remove the possibility of these connectors coming out during a match.
You could also epoxy a piece of a popsicle stick to the male and female
connectors, to hold the plug in place. Again, double zip tie the cables
to the bracketing mounting the camera near the camera, so the cables
do not get pulled loose from the camera.
We use the AMP mil-spec terminals, and the AMP crimper, available
from digikey. We have been using the commercial grade crimper, but
I have noticed some of the terminals slipping a bit during crimping
and am considering stepping up the mil-spec crimper to remove this
problem. The mil-spec crimper has a feature that prevents the terminal
from sliding as you squeeze the crimper, preventing a bad crimp.
We have never had a pull out on the amp mil-spec terminals,
and we test a few of these to desctruction prior to wiring the robot to
make sure everything is crimping properly. The wire always breaks
before it pulls out...
Before I worried too much about using shielded cables to remove
noise problems, I would use the analog inputs to make some
noise measurements. Your problems might be getting caused
by issues other than electrical noise on the wires.
With appropriate wiring methods, it takes no time at all to change an
RC, or spike, or victor.
Eugene
Quote:
|
Originally Posted by Rombus
As the electrical person for our team, I'm thinking of trying and designing a "Pull out" Electrical board. This idea i had after having issues with our RC and having to replace it quickly, and to ease wiring and make for an over all cleaner look.
So heres a few questions that should start me on my design:
1. Does anyone make drawer pulls or slides that don't have backstops or locks at full extension?
2. any suggestions on what i might try and lock it in with? I'm thinking about some form of clasp kinda like whats on tool boxes.
3. if i ran the battery connector into said electrical panel, Would it be FIRST legal to use the 50amp Anderson connector or would i have to go up to the 175 amp Anderson even though the battery has the 50amp version on it?
4. I know i can remote the program and reset switches, but there is no way to remote the lights on the RC or the lights on the victors/spikes correct?
5. We have had MANY problems with the TTL chip and TTL Connection on our RC and camera, Could we use some 4 conductor cable and connectors and mount the TTL chip flat? What about the possibility of directly soldering the wires onto the TTL Chip?
6. We were having some issues with the camera acting very funny in disabled mode and programming (Jittering, tending to go to 0, 0) And i Think it may have been due to noise in the PWM signal lines. is there anyway i can shield the wires better? Twist them around the ground line?
7. Final question, Do they make such a beast as a right angle pwm cable or something less break prone than the current pwm connections? chances are next year we will be running custom pwms, so I'm looking for the best connectors to use.
Thanks for any help!
|