FRC Java Beginner - Help

[Joe Johnson]

I was just about to post a similar question. Thanks.

This is our 3rd year and we have used Java in our first two years but we have lost our main programmer to graduation and coding mentorship has been spotty (at best). So we are really starting from scratch.

This is going to be a rebuilding year for our team in a lot of ways. I am pushing each of our subteams to come up with a list of measurable skills that the team should acquire prior to kickoff.

To that end... ...beyond learn Java, the WPI Library, etc. I have made this list of tasks/skills that the coding team should work towards:

1. Read Joysticks and buttons from Gamepad
2. Output values to a motor
3. Output values to multiple motors
4. Read values from a switch
5. Read values from a sensor (potentiometer, angular rate sensor)
6. Read values from wheel encoders
7. Display a value from the robot on the PC screen
8. Display a value in the form of a visual gauge on the PC screen
9. Understand how to use Debugging & Development Features of FIRST control system
10. Use Joystick values to control a mulitmotor drive system with and without a shifter
11. Implement various joystick scaling methods (e.g. “deadband removal”, “dynamic zeroing”)
12. Implement various output scaling methods (e.g. “linearize Victor”)
13. Implement a PID Feedback Loop on an arm or actuator
14. Implement a PID feedback Loop on robot wheels
15. Control a PID Feedback Loop via Joystick
16. Control a PID Feedback Loop via buttons
17. Use Angular Rate Sensor and Encoders to improve high speed “Drive Straight” Performance
18. Use Angular Rate Sensor and Encoders to improve low speed “positioning” performance
19. Basic Autonomous: sequence of steps in series
20. Medium Autonomous sequence of steps some series, some parallel
21. Medium High Autonomous including straight line robot motion back and forth with other steps
22. Difficult Autonomous robot motion including turns
23. Very Difficult Autonomous using camera to auto target using both arm and robot motion
24. Use NetworkTables to implement Full Robot Monitoring System
25. PC Based Vision System Based Targeting (height, distance, & angle wrt Robot)

What do folks think of this list? Would you add/remove anything? How about the ordering?

Do tell...

Joe J.

[Ginto8]

Originally Posted by Joe Johnson

PC Based Vision System Based Targeting (height, distance, & angle wrt Robot)

I would recommend doing this independently from the other tasks, and I wouldn't focus much on doing vision on the cRIO. The performance of a PC-based vision system is orders of magnitude better than one running on the cRIO, and the only major similarity between the libraries used on PC and cRIO is NetworkTables. It'll probably be most worth your time to just work on a PC version.

[tuXguy15]

Where could one start to try to get PC vision working? We would like to use javacv

[otherguy]

Originally Posted by tuXguy15

Where could one start to try to get PC vision working? We would like to use javacv

I would suggest starting by digging through 341's code and the related comments.

Between that and the openCV tutorials online, you should be able to make some decent progress.

A word of warning. The documentation for javaCV is terrible. Or I should say it was the last time I checked which was January/February of this year. The C++ variant seems to be their primary focus. Unfortunately the documentation isn't always 1:1.

Figuring out how to get things up and running in the off season will be a huge advantage to you.

[Ginto8]

A more-current resource you might use is our team's vision system for this year. It's not well-commented (yet -- I'm working on it), but it works on the same basic principles as Miss Daisy's system while also showing how you can make parameters that can be tweaked at runtime through SmartDashboard's properties window.

[tuXguy15]

Being able to see your team's robot this year really impressed me. Your vision system was amazing. Thanks for sharing!