We’re team 3992, a rookie team from Delray Beach, FL.
I’m posting here because we pretty much have our basic drive train right now, and have electrical components mounted, but I wanted to get a few words in from you since this is my first time doing this.
We have the PDB, 2 jaguars, cRIO, Digital Sidecar, D-Link Router, Battery, and killswitch mounted.
What else should we put on? Is there a “best” or "recommended way to set up the electrical configuration? If you have them, can you recommend or link us to some wiring diagrams or electric set-up guides? What gauge wires should we use, and for which connections? Where can we purchase additional electronic supplies?
You can purchase additional electric parts such as wire and terminals at local stores such as Radio Shack, Ace Hardware, or auto parts stores such as NAPA or CarQuest. You can also find a lot of electronic parts online at places like Digi-Key.
Put the jaguars in places where absolutely no metal shavings or other debris could get into them! This will ruin them!
In an effort to keep your robots COG low make sure these are as far down as reasonable. Also make sure the battery, main breaker, cRio, and digital side car are easily accessible. Your team will need to get at those fairly regularly throughout the season.
The rules specify where it needs to be seen from, don’t they? maybe [R57]?They have in past years. It’s mainly for the field personnel to tell if your robot is talking to the field system. So it needs to be visible from the front of the robot
So the field operators/head ref and others know the state of your robot. It has to be in a visible place where said personnel can see it. It has it’s own port on the sidecar, right next to the power input.
Yes, it required.
The light should be seen from any side of the robot. - we always try to keep our high on the robot.
This light shows the field team the status of your robot. Either have the light on steady, of how fast/slow the light blinks. Help the field people determine if there is a problem, along with the lights on the router. - which should also be in a higher location to avoid problems. (loss of signal)
The rockwell light is so that it is easy to tell your robot is working, it needs to go where it is easly visible. Your main circuit breaker should go where it is easy to get too. R29 lists the wire for the battery, R44 lists the wire gauges for each circuit. In general you should try to minimize the length of the cable, based on the current carry capacity. That is to say your PDB and battery should be very close together and your signal wire can be longer with out causing problems.
If you want to know about legality and rules, there’s this handy dandy thing called the manual. It will contain everything you need to know, favorite it and search for the info you want.
As for electronics, sensors will be your friend; the reason that factories have become more automated is because computer systems operate much, much faster at simple tasks and operations than any human can. Similar reasoning also applies to FRC robots; sensor systems can and will automate basic tasks, like shooting balls and loading them, and also semi-automate (help human operators) in more complex tasks, like driving around and navigating.
Personally, the most useful sensors that can be hooked up are, in no particular order, and I highly recommend you consider using, are:
Motor shaft encoders, for determining rotation speed
Ultrasonic sensors, for medium-range object detection
IR sensors, for close-range object detection
Limit switches, for close-range object detection
The accelerometer/gyro KoP combination, for tilt and speed referencing (making sure there aren’t bad readings)
Camera imaging (many uses)
One possibility that I’ve considered but never used is a current sensor, which is mainly as a fail safe for small, easily destroyed motors.
K,
This is a time that I must suggest you contact a veteran team in your area for a couple of hours of discussion. There are a lot of documents on line both here and on the First site that can help. Please look for my electrical presentation. While somewhat dated, most of it is accurate. For my money, here is a list of do’s.
Mount the PD and battery close to the center of gravity on your robot and make sure they won’t fall off when your robot turns over. You can’t run if the battery is laying on the floor. Insulate your battery terminals ASAP and keep them insulated at all time. The fully charged battery can supply over 500 amps. That is enough to weld metal, melt tools, and cause sparks.
Mount the PD and battery in the center of your electrical loads/speed controllers, this helps with losses and keeps wiring short.
Mount the 120 Amp breaker close the PD and battery but in a position where it is easily accessible to someone who has never seen your robot and who is trying to keep your robot from setting itself on fire.
Keep power wiring short! Yep, I think it’s that important to mention twice. Data, PWM, CAN bus, sensor and pneumatic solenoid wiring can all be long without any bad effects. Power wiring is a different story.
Make sure your Crio is electrically isolated from the chassis.
Make sure you supply power to all analog and digital sidecars and that you include the +5 volt regulator connected to the marked 12 volt supply connector a the end of the PD. This regulator will feed your wireless gaming adapter.
Be sure to wire the Crio to the dedicated +24 output on the end of the PD.
Make sure you do not have any whiskers sticking out of your connectors, anywhere on the robot and insulate all connections.
If you use crimp connectors, use the “tug test” to insure all crimps are properly made. Grasp the terminal in one hand and the wire it is attached to in the other and tug like crazy. If the connector pulls off the wire, replace it and try again. Loose connectors fail and heat up.
Use the color code and wire size minimums listed in the robot rules. Using small wire with small breakers won’t allow the performance from motors that you expect. CIM motors draw 133 amps when stalled. If you use #18 wire and 20 amp breakers smoke will result.
And as a PS, read the manual, three times at least today. Then reread a couple of more times and then be aware that Team Updates are published every Tuesday and Friday which will modify the manual. Those changes will initiate a manual revision. Last year we were at Revision K at the Champs.
Lots of good advice already given. In addition, try to find someone who is experience in wiring, preferably machine wiring. There are so many things to know about wiring such as tight connections, neat wiring secured and away from sharp edges and moving parts. In just two years of FIRST I have seen many robots fail through little wiring failures.
I’d recommend adding corresponding letter or number labels on the end of each wire, then a wiring list describing the gauge of each wire, it’s source and destination, as well as its function. A wiring list takes a bit of time to set up, but is hugely beneficial for quick fixes. It eliminates the need to trace a wire through webs and nests that will almost certainly build up on your robot.
Keep in mind that this board is missing a circuit breaker, which you must have (you seem to be referring to it as the “killswitch”).
Other things that you may want to take a look at are spiral wrap and the plastic routing chain that comes in the igus bag. They’re both handy ways of protecting long wire runs, and in the case of the latter, ensuring a constant direction of motion for said wire run as you actuate an appendage.
Thanks for mentioning that, i forgot ours was elsewhere on the robot that year.
You may someday decide to make your electronics removable like that panel, in which case certain crimps make it easier to remove and replace quickly like these anderson connectors. (also pictured in the left corner of the electronics panel i posted) http://www.powerwerx.com/anderson-powerpoles/powerpole-sets/
