What was the hardest to program this year in Java?

[Robototes2412]

I was going around, and I know that people make classes/interfaces for doing the bizzare things that are used frequently on their robots.

For me is was getting DigitalInputs working, to do that, I made this class:

package com.shadowh511.mayor.inputs;

import edu.wpi.first.wpilibj.DigitalInput;

public class Switch {
    private DigitalInput source;

    public Switch(int channel) {
        this.source = new DigitalInput(4,channel);
    }

    public Switch(int slot, int channel) {
        this.source = new DigitalInput(slot,channel);
    }

    public boolean oldGet() {
        return this.source.get();
    }

    public boolean get() {
        if(!this.source.get()) {
            return true;
        } else {
            return false;
        }
    }
}

what you use to call this is:

Switch ballSwitch = new Switch(4);

or

Switch ballSwitch = new Switch(4,4);

I recommend the bottom one just to be on the safe side.

[SavtaKenneth]

For us it'd have been making our own Gyro code. We used three gyros on the robot and so had to make our own. It ended up being just as accurate as the WPI code and now we are adding some filtering to it to solve for irregularities.

[Robototes2412]

I gave up on the gyro after 3 hours

[FRC4ME]

I think the hardest part for us was working with the Cypress I/O board. I can't count the number of times I got the "Enhanced IO Missing" exception while trying to read inputs from that thing. It turns out you can't read them in robotInit() - you have to wait about a second for the board to be ready before attempting to read it.

[Robototes2412]

I hated that too.

I used a seperate class for the cypress i/o module (com.shadowh511.mayor.inputs.DomBoard) that did all the work by itself.

[cybiko123]

Some issues we had included:

1. Getting the cRIO not to throw random exceptions when using known working code (gotta love that cRIO imaging tool...)

2. Getting our drivetrain working (and not curving). We ended up scrapping RobotDrive and implementing our own Drivetrain class.

3. Making sure we didn't lose communication.

[FRC4ME]

Oh, and I forgot to mention: finding and fixing bugs in WPI's code.

So far we're overriding three of WPI's classes with our own versions: PWM, because someone forgot to cast two integers to doubles before dividing them; Encoder, because someone divided by 0.25 when they should have divided by four; and DriverStation, because the scaling on the joystick axes is wrong (it goes from -1.0 to 0.9 rather than -1.0 to 1.0 due to the use of two's complement).

Not that I'm complaining; when volunteers write 20,000 lines of code there are bound to be a few errors. In fact, I'm glad WPILib isn't perfect, because then my programming team would have nothing to do after week one.

[Robototes2412]

It was actually student voulenteers

[davidthefat]

The hardest and most frustrating is debugging... But a lot of times, it ended up being electrical that was messed up... e.g. IR Sensor not lined up, Pressure sensor not wired up correctly, and ect

[cybiko123]

Was anyone else having a problem getting the debugger to work?

[LukeS]

The hardest part of programming is always convincing everyone that it's not a code problem! Fine, it was twice, when someone accidentally would comment out `break;' on one-line cases in switches.

Things we did abstract farther:
Our side kicker was incredibly complex. So, I created a the `hardware.SideKicker' class that made it work work like ``sideKicker.set(SideKicker.Mode.kLoad);''. It had 4 states: kick, load, close, and wait (which are normally run in that order). Beside that, I further broke the kicker down into the `hardware.sideKicker.Loader' and `hardware.sideKicker.Latch', both of which `hardware.SideKicker' used. Even after that, all the timing logic and such is still fairly complex, but I did manage to make it pretty zen.

Same thing with the front kicker, although it is a lot more straight forward (kick and load), no timer issues other than the 2 second rules of the competition.

We also further abstracted the driverstation ``LCD''.

• LCD.lines[0-5] is an array storing the desired text.
• LCD.update() updates the hardware based on the array, adding spaces if necessary (having parts of long numbers left over can be very confusing when debugging a problem).
• LCD.println(str) adds a line, scrolling the other lines (this changes the array, and runs LCD.update()

[Robototes2412]

to be honest, i stole my team's driverstationlcd class from the Comet's code

[Lord_Jeremy]

Hah, I think the most complex thing in my code was the kicker stepping system, though the order processing system wasn't all that simple either. Of course the autonomous handler and the stepping manipulator building-blocks system were way more complicated but those were disabled in the competition version of the code. This was simply because I had to finish them after shipping and the mentors didn't want untested code in competition. In regard to WPI crap, I ended up doing a bunch of extensions just so I would have my own inheritance tree to play with, and I had to fix some bugs along the way.

Oh and speaking of shifting the blame away from programming, I had some serious issues with that. For two days at our regional the robot didn't move on the field. It worked just fine in the pit, tethered and it worked fine at school on wireless. Eventually I solved the problem by reimaging the cRIO, but that was after the mentors had ordered me to remove the Java code I wrote and replace it with the default LabView code. (There was a lot of fighting about this. Apparently someone from another team that used Java but switched to LabView came over and said that the Java code was the problem.) Unfortunately, this whole mess has now prevented us from going to Atlanta, although we've already paid the fee...

[Egg 3141592654]

Originally Posted by Lord_Jeremy

For two days at our regional the robot didn't move on the field. It worked just fine in the pit, tethered and it worked fine at school on wireless. Eventually I solved the problem by reimaging the cRIO, but that was after the mentors had ordered me to remove the Java code I wrote and replace it with the default LabView code. (There was a lot of fighting about this. Apparently someone from another team that used Java but switched to LabView came over and said that the Java code was the problem.)

Interesting, because something similar happened, except by willingness of I. I have the robot coded in not just java, but in Labview as backup (boredom produces somewhat valuable things sometimes). Since I never had time to test either code before the robot was shipped, I scrapped the java code and perfected the Labview code. It was sad to see 4 days of hard work go to waste and STILL nothing worked (NOTE: it was not a code error that killed our robot, someone just wired all pwms backwards).

As for the actual question, hands down our parallel kicker. It wasn't the code itself, but the implementation and lag prevention that was very difficult.

[Robototes2412]

i solved a similar lag problem with a kicker thread