Re: Any Team Using A Timer?
 

I'd advise against it. There is a reason that you have a 3rd coach, whether another student or a mentor. Let them control when you deploy your minibot, its simply not worth the risk of somehow losing sync with the FMS.

Re: Any Team Using A Timer?
 

Has there been a history of the FMS counting seconds differently than the rest of the planet?

Re: Any Team Using A Timer?
 

Yes. Last year, and the year before, the teleop time period was significantly longer than it should have been - by 4-8 seconds as I recall. I timed it using a timer on our robot after one of the other mentors brought up the issue here on CD.

I would caution *anyone* who expects to use a timer to deploy to have some method of testing it during your first couple matches to insure that they've corrected the problem.

Re: Any Team Using A Timer?
 

I'm also sure in your many years of FRC you've seen the robots get stuck for a few seconds longer than usual after autonomous. It's things like this that worry me when designing a timer. We have no idea what's the cause of pauses like this and what may be happening.

If you start the timer in the wrong place, it may be running during that same pause....
ie the same reason you get a head start to initialize your camera could break your timer because yes it uses the same length of a second, but it may not start with the FMS. I've seen all sorts of weird things happen on the official field that I never saw in testing.

Re: Any Team Using A Timer?
 

All cautionary tales assimilated, gents! Thanks!

Re: Any Team Using A Timer?
 

It's trivially easy to start the timer when the robot starts the teleop enabled stage. It is pretty much done for you (at least in LabVIEW).

Re: Any Team Using A Timer?
 

Perhaps, but like I said, although it appears to be foolproof, its a huge penalty if it allows you to fire too early (penalty + no points for minibot) and a huge disadvantage if its late (deployment is everything). Although it shouldn't mess up, it really is not worth the small risk for the even smaller gain.

My two cents.

Re: Any Team Using A Timer?
 

My point is not regarding the ease. Believe me starting a timer in your teleop function is simple. My point is there is no guarantee that what your code perceives as entering and the start of teleop mode is the same as the FMS actual field time.

Where it looks straight forward in your code, there is a lot of code behind what are you doing to make it that simple. Do not assume that what you see as the teleop loop is called exactly when teleop starts. Also don't assume you can simulate the FMS system on your control system. There are nuances to their system that are not exposed to the driver station software.

Re: Any Team Using A Timer?
 

This uncertainty is why there's going to need to be some human interaction in here to remain reliable all of the time, unless you use the idea of detecting the base. Not sure how fast the cRIO would be at this, though, if you're using NIVision.

Re: Any Team Using A Timer?
 

Two possible cases:
1. You driver was too concentrated on the field and didn't get to the climbing pole on time. In that case, no programming in the world can save you. Unless you plan on making your entire dashboard flash red and emit loud obnoxious noises from the driver station. (which we're doing)

2. Your driver gets to the climbing pole on time. The average teenager reaction time is 160ms. The driver is most likely faster than average. Even if you can get a timer to work perfectly every single time, regardless of field conditions, you'll only be getting a 160ms head start every time you deploy your minibot.

I think it would be more wise to invest your time and resources into building a slightly faster minibot/deployment system, instead of spending all that time developing a precise timer (that measures field conditions) that will give you a 160ms advantage. Something which a slightly more charged battery would give you.

If you're afraid of a trigger-happy driver, a better solution is to design a system where both drivers + the coach have to insert their unique physical key and press their launch triggers at the same time to deploy the minibot. Kinda like a nuclear launch device safety mechanism. It'll be completely fool-proof.

Re: Any Team Using A Timer?
 

Well, both drivers AND the coach would be a rules violation, because the coach isn't allowed to touch the controls.

My team DID do a similar system last year - in order to deploy our hanger, the driver had to be holding down both autobalance buttons, THEN the copilot could press the trigger. It worked fairly well, AND prevented our trigger-happy copilot from deploying right away.

Re: Any Team Using A Timer?
 

Has anybody done any tests this year to determine whether or not this years matches are running a little long like people were saying earlier in this thread? or has anyone had issues with deploying slightly early/late if they were using an automated system?

Re: Any Team Using A Timer?
 

In our field tests using time only, the field timer was usually off by less than a second, but in the longer direction, which would result in early deployment. 987 uses automatic deployment with a timer and a photoresistor sensor so as soon as the tower turns blue/red the bot deploys. There is of course a manual button in case we aren't at the tower when it turns or if the sensor fails to read. I would not suggest using time alone.

Re: Any Team Using A Timer?
 

Why do you have to choose one or the other. If a team has mechanical and programming students, they could work on both options -

The difference between 1st place and 2nd place is 10 points, and 10 points has determined a lot of matches.

Re: Any Team Using A Timer?
 

We designed a sensor to detect the tower's on/off sequence. It initially began as a tower illumiantion and color sensor, but the brightness of the field lighting pretty much monkeywrenched that idea. There are six transitions of light to dark (you can count them if you disagree). After the sixth transition a digital high is sent to the cRio to tell it to deploy the minibot. Works like a charm!