Brake overtravel wiring

[PSURacing]

I searched the forum but haven't found anything on this for about 2 years...
I was just reviewing the rules for the brake overtravel switch. It states "Repeated actuation of the switch must not restore power to these components, and it must be designed so that the driver cannot reset it." I am not an electrical guy, but with a team of 6 here i am. My original thought was just to wire the OEM key switch wiring in series with a push pull switch (non spring loaded) on the master cylinder. But this "repeated actuation" has thrown me for a loop. Any sugestions would be great.

[PSURacing]

I searched the forum but haven't found anything on this for about 2 years...
I was just reviewing the rules for the brake overtravel switch. It states "Repeated actuation of the switch must not restore power to these components, and it must be designed so that the driver cannot reset it." I am not an electrical guy, but with a team of 6 here i am. My original thought was just to wire the OEM key switch wiring in series with a push pull switch (non spring loaded) on the master cylinder. But this "repeated actuation" has thrown me for a loop. Any sugestions would be great.

[Nitesh]

for the brake overtravel, we use a switch that switches off all the power when pushed but has to be turned so that it can be switched on. this way, the brake pedal can only turn all electricals off as it can only puch the switch but not turn the knob.
i'll try to get a picture of the switch but don't have it now.

[Laurence]

All our power runs on a relay which is latched on by the primer switch. When the BOT is pressed this relay is unlatched and all power goes off.

[BStoney]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Laurence:
All our power runs on a relay which is latched on by the primer switch. When the BOT is pressed this relay is unlatched and all power goes off. </div></BLOCKQUOTE>

Do something very similar, just a simple SPST toggle that is actuated by the brake if it overtravels (i.e., loses pressure in the system). Here's a pic from our '05 car, you can see the small blue toggle behind the brake pedal about dead nuts center in the photo.

http://img249.imageshack.us/img249/3906/img2029hn1.jpg

[Pete M]

We also use a latching relay. Our ignition on button sends power to the coil of the ignition relay. The relay's output also sends power to its own coil through a diode. The other side of the coil is connected through the dash kill switch and the brake over-travel switch to ground. If either of these is turned off, then the loop is broken. To turn the engine on again, the switch must be reset and the ignition on button must be pressed again. This is pretty simple to do and satisfies the rules.

[Erich Ohlde]

the repeated actuation thing means basically that you can't run a latched button on for the over travel. i.e. you can't over travel the brakes, which kills the ignition, then over travel the brakes again to cycle power back on.

[Pete M]

Flicking the over-travel switch back on doesn't turn the ignition back on. It resets the loop, but since the relay turned off, it's no longer driving its own input. You have to hit the button on the dash again to turn the ignition back on.

For added unnecessary safety, we use a toggle switch as our over-travel switch. Repeated actuation just keeps bashing it into the off position. The electrical circuit above satisfies the rule though. I've toggled the switch as fast as i could and the engine still dies and doesn't come back to life.

[Scott Borg]

Our team uses a normally-open push button switch that simply shorts power to ground, which blows the ignition fuse. The car is very much disabled until that fuse is replaced.

-s-

[Kurt Bilinski]

Nice idea, Scott! Cheap, simple, and light are hard to beat, and no relay to fail either. The fact that it consumes a fuse is trivial given the issues that caused it to be needed in the first place.

(Just as long as you aren't also making your own carbon fiber fuses, lol)