Lots of Electrical Questions
 

We are a future 2005 rookie team. We tried this year but couldn't get the registration fee, but we're building a robot anyway to practice. Electrical is one of our weakest points. Here are our questions, well a few of them.

1) We have an Edu RC, will have either a 2002 FIRST RD or a 2003 one, and are trying to find at least close to an official battery. What other electrical stuff do we need?

2) I am pretty sure we at least need a fuse box. Where does that go and how do we connect it to where it needs to go? And where can we find one and how much does it cost?

3) Where are we supposed to connect the motors to? And what about pnuematics. Where does the compressor hook up to (provided we can find one to use) and where do the solenoids (we have two of those) hook up to?

4) An engineer on my other team (226, I'm a mentor/alumni), one of the engineers someone said something about being able to connect the two RC's (The Edu and the FIRST one) so that our programmer can still use C (What he's been learning) but we can use the operator interface from the FIRST one. Can anybody explain this furthur?

Everything we have so far (6 motors, 2 pistons, 12 bearings, surge tank, 2 solenoids, 8 sprockets, chain, other cool stuff) was donated by 226. Thanks TEC CReW!

Allison

Re: Lots of Electrical Questions
 

Its not clear what parts and controller you have?

the EDU bot from last year only runs Pbasic, not C (and by last year, I mean the 2003 competition year - the EDU robot controllers for this year were actually shipped out in the fall of 2003, but they are considered to be 2004 units)

Have you found the documentation at www.innovationfirst.com ? the documents for the older EDU bots is all there in the 'previous' archive section.

if you have the full size robot controller from a previous year, then you will want to take a look at the archived manual from that year at www.usfirst.org - they have all the wiring diagrams in the robot section of the manual - bwteeen those two websites you should be able to find all the instructions and drawings and schematics you need to expeiment with what you have.

Good luck towards next year - hope to see you at a regional.

and please feel welcome to continue this discussion with any questions you have - I dont mean to dismiss your questions by pointing you towards websites - most of what you need to know is already there.

Re: Lots of Electrical Questions
 

If you have a 2004 Edu RC (which runs C) you can interface it to an old PBASIC Edu RC or old FIRST RC in order to be able to use the old OI and controls to control the new 2004 Edu RC. I wrote some software & documentation for this and it's available here. If you try to set this up and have problems please let me know and I'll do what I can to help.

Best of luck to you getting a team together for 2005!

Re: Lots of Electrical Questions
 

We had enough money to pay our down payment for the EDU, so we have the 2004 EDU kit, but an old full size RC, or will have an old full size RC.

I guess a better question would have been, After the battery and the controller, what is the bare minimum of other electrical stuff. We're running on a 300 budget, hence the reason most of the other stuff was donated.

Hmmm. It was rather depressing when we first found out that we couldn't officialy compete, but I've come to realize a practice year is definiely a good thing. I'm almost glad we weren't stuck trying to figure all of this out in six weeks.

Allison

Re: Lots of Electrical Questions
 

If you're using any of the full-sized motors, you will need some Victor 884 Speed Controller modules (883s will probably do for now) and/or some SPIKE Relay Modules.

Re: Lots of Electrical Questions
 

We have two 3/8" drill motors, two Van Door motors from ?2001? I think, and two other motors that I'm not sure what they are. They are about 2 in long and have a square shaft covered in plastic that lies perpendicular to the motor. I'll take a picture at meeting tonight and post it.

Re: Lots of Electrical Questions
 

Then you will need some speed controllers for the drill motors and the van door motors, and spikes for the window motor.

Re: Lots of Electrical Questions
 

Okay. What do speed controllers and spikes look like, how do I explain to the team what they do, where can I get some, and how much do they cost.

Allison

PS- Sorry about asking so many questions but I really know nothing about electrical, and as I am the team leader I am expected to know something.

Re: Lots of Electrical Questions
 

I think they retail for $120 or so each, but I'm sure some teams will have extra 883s which can no longer be used in competition, but are fine for everything but the latest drill and chiaphua motors. The Victor is a square base with a LED on it, and a mini tower coming up with a fan mounted at the top. The SPIKE is a little box which has either a red or blue SPIKE label on the top. Both are labeled very prominently, so if you see one you'll know it.

Re: Lots of Electrical Questions
 

OK thanks. And when we put these on the robot, We wire the motors to the victors/spikes and the victors/spikes to the RC?

Re: Lots of Electrical Questions
 

A nice electrical diagram put out by FIRST can really help you out a lot:
http://www2.usfirst.org/2004comp/200...rev0120704.pdf

Re: Lots of Electrical Questions
 

Thanks DJ.
So to make sure I have this all right.

The two 3/8" drill motors each go to a victor 883. The victors connet to the circcuit breaker (same this as a fuse box?).

The two van door motors are the same as the drills- motors to victors to circuit breaker.

The two window motors each go to a spike which connects to the circuit breaker.

For the pnuematics, both the solenoid and the compressor connect to spikes.
-Are the spikes really necessary?
-Why do the solenoids we have have four wires each? Do they all connect to one spike, or do we need two spikes for each solenoid?

More questions.
-Do we need more than one circuit breaker?
-How do we connect the Circuit Breaker to the RC?
-Can the 2004 EDU RC handle all that, or do we need to connect that stuff to the old full size RC?

Allison

Re: Lots of Electrical Questions
 

You must have 1 circuit breaker per powered part. You do not connect each circuit breaker to the RC - only one 20 amp, which is used for powering the RC. The EDU RC, I believe, will do fine.

Re: Lots of Electrical Questions
 

Not to be pedantic but you can't use Victor 883's. You need to use Victor 884's (which have been available for the last two years).

As for the spikes connected to the pneumatics, yes they are necessary. Without the spikes it would be impossible to switch the compressor and the solenoids on and off.

You most definitely need more than one circuit breaker. Each Victor gets placed on its own circuit breaker. If the Victor is driving a drill motor or a CIM motor, it should be attached to one of the 40 amp circuit breakers. For any of the other motors, it should be attached to a 30 amp circuit breaker. The spikes which drive motors are connected to 30 amp circuit breakers while the spikes connected to solonoids are connected to a 20 amp breaker. The robot controller is a 20 amp breaker.

To connect a circuit breaker to the RC, you need to put the circuit breaker in series with the positive power terminal for the RC.

You need to use the full size RC on this year's robot. You can't use the EDU RC.

Matt

Re: Lots of Electrical Questions
 

We're not officialy competing because we couldn't get our registration fee, but we decided to build a robot for practice, because we plan to compete in '05. Well actually, It's not just for practice, but we haven't released other plans for it yet, because they're not all ready. OUr drill motors are the old 3/8" ones, so we were going to use the Victor 883's because we were kinda hoping that there might be another team that could lend them to us, because we can't afford them. Also, we have and old Full Size RC, but we're using the EDU one for most stuff (we're using the Full Size for the OI and the EDU for everything else) because it would be a waste of time for our programmer to learn P-basic for the Full Size RC. Thanks for your help.

Allison

Re: Lots of Electrical Questions
 

I believe the 883s are good for any drill motors that aren't last year's or this year's, so you should be fine...

Re: Lots of Electrical Questions
 

We can break things down into to larger categories, analog and digital. There are certain components on the robot that are one or the other. Basically, an analog signal is going to be anything from 0-254 giving a variable output. This is what you want to use on anything relating to a drive motor or in general any motor whose value needs to change. Then we have components that are digital. Now, digital components are either on or off.

1)You have this speed controllers (black box thing with a fan on top of it)-
Now what this does is offer an analog signal to your component in order to get it moving at a variable speed. Case and point, you want to use this on a drive motor(s) in order to get varying speed.

2) You hvae a spike (the smaller unit with four "prongs" sticking out of it)-
This is offers the digital signal to devices that run off of this. This means that it is outputting either a 0 or 1 either on or off. So, you would hook this up to a pneumatic which would give the initial on/off signal.

Now essentially everything you have will go through the breaker panel. This is to protect your electronic devices. Why? Well, if for some reason a certain device begins to pull more current (amperage) than it can handle, the fuse/breaker will "blow" and will protect the device from burning up. Now here, we use the auto-resetting breakers (black with two thick prongs coming out the bottom). These are much better than a regular fuse. With a fuse, too many amps are being pulled and the metal inside breaks and no more electricity is sent through, however, that device will no longer work. Then we have the auto reset breakers which, if too much current is pulled, will "trip" or cut the electricity going to the device and then a few seconds later, will re-allow electricity to flow, so long as that amperage is not being pulled.
Drop me a message on here and I will email/send you the pdf file of the powerpoint presentation I used during the preseason with our students. It discusses many analog and digital sensors, as well as PWM's, victors, spikes, the RC/OI etc.

If you have any other questions....feel free to post them.

Re: Lots of Electrical Questions
 

It seems like you're a little unclear on the meaning of the power diagram. The big power diagram shows all the pure power connections of the robot. These are large gauge wires that transmit electricity from the battery to the motors.

Seperate but related, are the control connections. Victor 883s have 3 wire PWM cables connected to them that you connect to PWM headers (pins) on the robot RC. This is how the RC gets instructions to the Victor to control the speed of the motor. Spikes work similarly, but go to a seperate set of headers.

The best way to find out about this is to go to www.innovationfirst.com and look at all their white papers and documentation about victors and spikes.

Re: Lots of Electrical Questions
 

Don't mind me. I need to read more carefully in the future.

Matt