Rookie Electrical Questions

[varunsrg]

Hey guys I am rookie this year at my robotics team. I am doing electrical. I wanted to know the basic things an electrical needs to know help build the robot. If any of you guys have like a walkthrough or some kind of website where I could get educated please post and help me. THX

[MrForbes]

Welcome to the fun of build season!

First place to look is at FIRST

http://www.usfirst.org/community/frc...nt.aspx?id=452

Section 8 - The Robot is mostly what you need, be sure to download and read all of this stuff! The rules are most important, but the Power Distribution Diagram and Tips, Guidelines and Good Practices document explains how to wire up the robot and important info about motor selection, etc.

[JesseK]

Big tip: make sure you use the proper gauge wire for the motors and other components. The rules for wire gauges are there for a purpose, and that purpose to prevent you from inadvertently catching your robot on fire due to a bad gauge + bad crimp combination.

To get you started, the first thing we do is crimp quick-disconnect connectors to the end of every motor, victor, and spike. This gives us practice with stripping/crimping, which may not be a glorious job but there are noticable (10-20%) robot performance differences if you're good vs. bad at it. It will also allow you to quickly change the configuration of your electronics board setup.

Pegboard + zip ties is a great way to quickly mock the board up as well.

[team1203 4life]

some advice dont lable your wires with ductape because the judges will flip out and make you take it off cause ductape is illegal

some other advice is for you to get out will you still can run away run far away before you lose your mind like the rest of us

[David Brinza]

The best resource available to all teams is the :
Guidelines, Tips and Good Practices Manual

This document is the closest thing to an instruction manual for building the robot. If you follow the guidelines here, you should have few problems with the grumpy robot inspectors such as myself.

[clark_noah]

keep your electrical board organized.... this was a big problem for our team, because when everything is confusing, it is hard to re-connect wires if they do fall off...

[keen101]

Originally Posted by clark_noah

keep your electrical board organized.... this was a big problem for our team, because when everything is confusing, it is hard to re-connect wires if they do fall off...

Yes, that is the best advice you can get. keep your electronics organized and very accessible. (also have plenty of extra PWM's)



also this may come in handy.
http://www.ifirobotics.com/frc-robot...overview.shtml

[vhcook]

Make sure you really understand what's going on in the power distribution diagram. If there's something there that you can't figure out after reading through the rules and the tips and good practices, ask.

Correctly stripping and crimping the wires is the most essential skill. Also make sure you put enough tension on the screw connections on the Power Distribution Block and the Maxi Block. All of your connections should pass the "jiggle test" -- if you jiggle the wire a bit, it shouldn't pull loose. If it doesn't pass the jiggle test, it's likely to work loose in competition, which can result in your robot being disabled, becoming immobile, or, in extreme cases, catching fire. Use the proper gauge wire for the breaker protecting the circuit (bigger wire is ok if it fits, but will cost you weight).

We're using a lot of current here, so don't skimp on the electrical tape to cover any exposed conductor, particularly your battery terminals once you've got the Andersen connector hooked up.

Make sure the main breaker button is always easily accessible in case you need to do an emergency shutdown (you need to be able to get to it without having to remove a cover first, but you'll want to position it so that other robots/trackballs aren't going be able to accidentally shut you down).

Make sure you leave enough room by the robot controller to be able to get the serial cables in and out -- those bulky connectors are not terribly maneuverable. (That's the mistake we made as rookies.)

Label wires at both ends, especially the PWM cables to the motors. A labelmaker is your best friend.

You're going to want to build or buy a disable/autonomous mode switch to hook to the OI for testing purposes. During actual matches, the field will take care of that for you, but for practice, you'll need a set of switches.

[keen101]

Yes, a disable/autonomous switch comes in handy. I think the wiring diagram is on the IFI site.

I was not aware you could buy one though.

[redbarron]

Originally Posted by keen101

Yes, a disable/autonomous switch comes in handy. I think the wiring diagram is on the IFI site.

I was not aware you could buy one though.

I know AndyMark had one last year they have a clean design and are reasonably priced.

[MrForbes]

Originally Posted by redbarron

I know AndyMark had one last year

yes, here it is

http://andymark.biz/am-0016.html

[Al Skierkiewicz]

Originally Posted by varunsrg

Hey guys I am rookie this year at my robotics team. I am doing electrical. I wanted to know the basic things an electrical needs to know help build the robot. If any of you guys have like a walkthrough or some kind of website where I could get educated please post and help me. THX

As pointed out, reading the robot section and Tips and Guidelines are the best start for rookie teams. If you have further questions, you may ask here or PM me and I will try to answer your direct questions.
Please follow the guide for wire size selection as it closely relates to the breakers you use in your design. My recomendations are to feed all Chalupa motors (CIM), Fisher Price and the compressor with #10 wire as short as possible. Use the terminal block to distribute loads and returns so that currents are not shared in the same wire. Above all, any wire used in the terminal block must be stripped 5/8" before insertion. Any less and you will push the wire out of the terminal when you tighten the screws.

Finally, the WPI site should have some of the rookie workshop presentations up in a few days. When they are posted I will alert you here. There is an electrical presentation in PowerPoint that will be available.

[Billfred]

One other good practice, if you have time (ha): Read Al's posts (you can click to get a list from his profile or postbit). There are many electrical nuggets of wisdom tucked in between his caption contest entries.

[lukevanoort]

Originally Posted by team1203 4life

some advice dont lable your wires with ductape because the judges will flip out and make you take it off cause ductape is illegal

some other advice is for you to get out will you still can run away run far away before you lose your mind like the rest of us

That is not true:

Originally Posted by Section 8: The Robot

<R38> Adhesive backed tapes shall not be used as a structural fastener, or to connect two or
more parts together. Adhesive backed tapes may only be used as follows:
• Textured or coated tapes may be used to provide an alternate surface finish or treatment to a
portion of the ROBOT.
• Velcro tape, any hook and loop tape or double-sided sticky foam may be used for attaching
components to the ROBOT.
• Reflective tape may be used with optical sensors in small amounts.
• Adhesive backed tape and labels may be used for labeling purposes on wires, cables,
pneumatic lines, etc.
• Electrical tape may be used as an electrical insulator.

(Emphasis mine)

You may want to bring a printout of this rule with you though, it is very possible to get inspectors who don't know the rules very well (I've had it happen at least twice). Also, based off of the posts on CD, tape-related rules seem to be the most inconsistently enforced of the inspection rules.

[Al Skierkiewicz]

So that no one will be confused...
The no duct tape rule comes from on high and is not part of the robot rules. It is a well known and long held belief that Dean does not want duct tape to appear on FIRST robots. Other adhesive backed materials will be evaluated per the rules by your inspectors.