Re: Bypass Disable Switch
 

On a vex controller this command will put the robot into autonomous,
I don't know if it will work on the full sized RC, but it might. I place this in the User_Ini function.

Re: Bypass Disable Switch
 

From the tx_data_record struct in the 2006 frc code:

The variable exists in the frc code at least, but there's only one way to find out if it works :p

Re: Bypass Disable Switch
 

that means you are only allowed to use it if you are designing an autonomous time machine.

Re: Bypass Disable Switch
 

Wow, thanks for all your replies guys! This is a robot where a person rides on it, which is why we need to be without an OI. I was thinking of just leaving the OI and RC together, always tethered, but I think I will just set the team number to 0. We can do without a radio control mode or anything. There is also a deadman's switch on the robot itself, as well as a main breaker switch, and also a Start switch, so there are no worries about it taking off without a rider :P

Re: Bypass Disable Switch
 

This confuses me. Having an OI doesn't necessarily mean lots of joysticks and controls.

It sounds like your best/easiest solution would be to have your start/stop, deadman's, and any other switches connected to the OI, then tether it to the RC. You could mount these side by side out of the way if you have the room.

Software-wise, you would just a simple state machine with the following transitions:
Then your On state would simply run whatever autonomous actions you want.

Re: Bypass Disable Switch
 

this all depends on how your deadman switch is implemented. When everything is working correctly then the deadman switch will always work

but you need the kill switch for when everything is not working - when some type of failure has occurred - or your SW has jumped out of its loop

that is precisely what the disable switch on the OI is designed for, its outside the part of the design that you have access to, so there is no way you can inadvertantly mess up its functionality.

Having access to the main breaker right off the battery is a good 2nd choice - but even that, if you have to look to find the breaker and get your hand on the level and think about which way to push it, while the robot is carrying you or someone else in a nasty direction..

The kill switch has to be a no-brainer to use - you hit a big red button, the robot stops (no matter what).

Re: Bypass Disable Switch
 

if the dead man switch is not wired to the OI comp-port disable function then you cannot guarantee it will work when needed.

if your SW gets stuck in a loop or does not operate as designed, then it may not read your deadman input switch, or respond to it correctly. And that is when you will need it, when your SW has bugs and your bot goes open-loop.

The real issue goes to the title of this thread: Bypass disable switch. :ahh:

Go into any engineering lab and you will find thousands of dollars invested in test equipment that is used to test and debug new projects, to get them working the way we want them to.

Nobody can design complex systems like robots and get them working perfectly the first time. Thats why the Disable switch is designed into the FIRST control system, and designed in a way that its fool proof. No matter what you put in your code, when you close the disable switch all the outputs on the robot are disabled.

Dont get your mind into a place where you think you dont need it. Its not a bad thing, its a normal and necessary part of every engineered system - a fail safe way to 'pull the plug' when you need it.

Re: Bypass Disable Switch
 

Well, we got everything working software-wise without an OI.

KenWittlief, about bypassing the disable switch, yes, not having one is a terrible idea. However, instead of the FIRST disable switch, which would make us attach the OI to the RC at all times to get the robot running, we implemented our own. We actually used a jetski deadman's switch, which works excellent.

Re: Bypass Disable Switch
 

Yes, you have a deadman switch, but is it read by software, or is it actually opening the circuit to the motors? I hope it is the second one--these RCs have a tendency to do odd things when you expect them to do something right. For instance--our (team 68) autonomous in the IRI quarterfinals, first match was supposed to drive for .5 sec then shift to low gear. For those of you watching, it very obviously didn't do so. I still don't know why. So, for me, trusting the software is one thing I will never, ever do. We're human, and when we need things to work right, that's when we make the fatal mistakes. Please, for the love of (insert biblical figure here), put a hardware kill switch in--so when it has been activated, even if the software is still outputting full speed, the thing isn't going anywhere.

On a side note, how do you plan to power this power-sled? I thought about doing this, but when I thought it through I realized that our Exide match battery lasts about 2 minutes...then it's pretty dead. That isn't a very useful lifetime. And if you put the batteries in series, 6 of them would deliver 12 minutes. Still not very useful.

Good luck,
JBot

Re: Bypass Disable Switch
 

I have yet to see IT, but I do know they have limited packaging space for the controller. I'll have to see how they (geekTeam) implimented the dead man's switch on .... this thing.

I will say they they are normally pretty good about these things. Our robot dongle for auto mode is a dead man's switch - if someone let's go of the dongle, the robot stops.

I will also add that if the kill switch ISN'T hard wired, it will be easy to add that feature. Soon as you fall off, get off, or let go, IT should stop.

Re: Bypass Disable Switch
 

now you got me wondering too. When I read they were using a deadman switch from a jetski I thought "wow thats clever"

but after more thought, devices like that are designed to cut the power to the ignition circuit, or possibly to short the spark to ground so the gas engine will cutoff. I dont think they are designed for 100A continuous service, therefor it could not be in series with the main breaker, right?

so how exactly is the jet ski kill switch wired into the robot?

Re: Bypass Disable Switch
 

now you got me wondering too. When I read they were using a deadman switch from a jetski I thought "wow thats clever"

but after more thought, devices like that are designed to cut the power to the ignition circuit, or possibly to short the spark to ground so the gas engine will cutoff. I dont think they are designed for 100A continuous service, therefor it could not be in series with the main breaker, right?

so how exactly is the jet ski kill switch wired into the robot?

if your bot is sucking the battery dead in 2 minutes your drive train is constantly fighting against itself. A smooth running, well conceived FIRST robot drive train will only draw maybe 10 to 15 amps while the robot is running around (average current) - which would give you about 40 minutes on one of the supplied Exide batterys.

Re: Bypass Disable Switch
 

Kill switches are your frineds. our team has been building a powered dolly to carry driver and robot around. We currently have 3 kill switches planned all wired in series witht he diable port on the OI. we have the OI hard tethered into the RC and it stays like that.

We also built a robot that charges after the light and is supposed to stop when it gets too close. it does this in the defualt routine via a button on the OI which will enable charge! or human steering. Our OI for this demo bot also has a kill switch wired right to the competition port incase the code crashes while charging and simply setting it to human control wont stop it.

Re: Bypass Disable Switch
 

Ahh yes, the jetski switch handles practically NO AMPERAGE. It is just a signal strength current. It is currently software based, which will be improved soon. However, our drive system is currently so under powered, that you almost don't need a kill switch! (Just let it go, let the motors stall, and let the breakers handle it :P)

In our next revision, we will have some HIGH amp relays hooked up to it. This way, with a small signal current going through the switch, it can cut battery power to the whole device.

Re: Bypass Disable Switch
 

You only need to kill power to the RC for an effective deadman switch. If you cut power to the backup battery and the 12v source the robot will stop dead. The RC draws very little power.