A Reminder of Simplicity

[10intheCrunch]

We had about 8 batteries at competition this weekend, and kept cycling them through our three chargers...during elimination matches we ran close to out, but thankfully we didn't have to play any tiebreak matches and stayed powered through it all. If all else fails, I am almost positive another FIRST team would offer a spare battery (especially if they are not in elimination matches) if you are out of fresh ones. Even then, we had about 40 minutes between matches, so if you have 3 batteries you could have stayed powered through preliminaries...sorry if I am discounting teams that don't have the battery supply we do.

Perhaps my aversion to using sensors comes from the ease of using the whip to tap the balls off the tees. We don't have to turn and face into the ball; rather we run along the wall and in fact use the wall somewhat to correct our angle and hold straight. We are planning on putting a light sensor to detect the line and tell us where to stop to only hit one ball, but any more sensors would have only put more hardship on us programmers (we had enough to think about on the arms).

Another problem is serious sensor malfunction. Team 60, the team we collaborated with this year, lost in semifinals because their proximity sensor that was counting gear teeth was malfunctioning. Their autonomous mode, based on this sensor, then flung them into a wall, and they lost a pneumatic fitting, and all pressure. Eventually they lost the match and couldn't get repaired in time for the next one. With our dead reckoning, we can tap the wall a little hard, but we feel safer than if we were letting the robot decide things more.

[mtrawls]

The problem with dead reconking is that you are blind. Sensors give you some sort of input into the outside world. So, if someone rams into you, code based on the IR sensors will still function properly (provided the bot can shove pretty well!) ... or if the robot is placed down in a position where it veers off to one side, the IR code will not be effected ... and other examples abound.

SO far as the batteries, I believe you can only use the 2 they provide in the kit. I'm sure someone will get around to posting the specific rule, but I've got to be off ...

[Cyris12]

I personally believe that sensors would be more useful if your target was moving or at an unknown location. As it stands, teams have the exact position of stationary objects. I'm guessing most people use sensors for two reasons:

1) To generate outputs that would have been too complicated or innacurate to write manually.
2) To have your robot adjust dynamically to changing situations.

As for number 1, the outputs generated aren't usually too complicated (ie the robot just has to move in a straight line). With a little testing, it's possible to determine these values. I personally prefer to have values I know work hard-coded into our program, as opposed to rolling the dice with sensors.

I believe number 2 is less of an issue than people think. I'm not sure that:
a) More than a few robots will be able to reach the center with enough force and time to disrupt you.
b) Sensors will help if you are moved. Most of the dead reckoning programs aren't terribly complicated. They don't tend to involve intricate movements that can be disrupted easily. If something can move your robot enough to seriously hamper the dead reckoning program, I'm not sure sensors would help.