Re: Speed Controller brake/coast setting
 

:ahh: :ahh: i wouldent use a spike unless you wanted to ensure there was some rostin electronics! you can pick up a 5v relay at radioshack for 3.99... or if you wana get realy fancy check out digikey for a huge selection

Re: Speed Controller brake/coast setting
 

Hmmmm.....
Our team tried this last year, we had a set of pedals that acted like "brakes"
The way they worked was they overrided every signal and applied electronic brakes. That way, if we needed to stop, even if the joysticks were pushed all the way down, we could hit the brakes and the robot would come to a stop.
I built a relay box, that had four SPDT relays in it that were controlled simultaneously by a SPIKE.
As far a leagality is concerned... We asked the Q&A and got an ambiguous answer... I will see if I can find the exact response. If time permits we plan on doing the same this year. But instead of four realays we have one 4PDT relay we will use.

Good luck!
-Andy

Re: Speed Controller brake/coast setting
 

Andy,
Bad news...Last year and this year are not very much different in use of the custom circuit board....
5.2.8 Custom Circuit Rules
<R50> The use of additional electronics is intended to allow teams to construct custom circuits for their robots.
The custom circuits may be used to indirectly affect the robot outputs, by providing enhanced sensorfeedback to the Robot Controller to allow it to more effectively decide how to control the robot. The custom circuits must draw power from a 20A circuit breaker. Smaller value fuses may be incorporated into the custom circuits for additional protection. All outputs from the custom circuits must be connected to the analog inputs,digital I/O, TTL Serial Port, or Program Port on the Robot Controller.

The way I read that, a custom circuit may not talk to a speed controller. If I were to inspect your robot last year, I would have had to rule against you. Sorry.
The same rule applies for the use of relays that are driven by spikes. The answer in a nutshell is "NO".

Re: Speed Controller brake/coast setting
 

The Servo will not move if there is no force applied to it on power-down.
We are using a servo to hold a brake mechanism for our winch. When power off occurs, the spring tension will rotate the servo to a non stressed position.

For the purposes of activating a switch, the servo will not be "loaded' and therefore work for you.

Phil

(PS. I fly R/c planes and gliders so I know servos :)

Re: Speed Controller brake/coast setting
 

How do I connect a wire to the brake pins on the Victor 884? I need like a jumper on a wire. I assume also that the default for the jumpers is to coast. That is that if it sees no jumper at all, it will coast.

Re: Speed Controller brake/coast setting
 

Nope, the default is brake, and the Victors come with a jumper. If you need to extend that, I would suggest using one of the triple-wire data cables that are used to hook up the spikes and victors. I think it'll fit.

Re: Speed Controller brake/coast setting
 

This question was answered in the Q&A today (ID: 893):

Unfortunately, the answer is no. You can’t legally wire a digital out to the Victor, but it might work. Ground loop problems are tricky and usually produce noise. They usually occur in audio/video systems.

You could probably stare at Victor 884 and RC schematics for hours debating about whether a ground loop problem would exist. Basically, the digital out current leaves the RC and must return to ground through the Victor (instead of the RC), thus creating a ground “loop”. This could possibly be solved by connecting the ground pin of the digital out to the A pin (which is grounded) of the Victor, but this depends on the internal wiring of the Victor and could produce problems of its own. It really doesn’t matter. FIRST said we can’t use this method and that is all that matters.