Archive for February, 2011

24
Feb
11

FIRST Competition Season

FIRST Robot build season for 2011 is complete and now it’s on to the FIRST Competition season. Starting March 3rd the FRC events begin, time for your robots to pucker up…assuming you put that feature on your robot.

I’m going to be a volunteer at the San Antonio FIRST Regional event. I’m going to be working Field Technical stuff. I would appreciate it if anyone is there would drop by and say hi. Since you don’t know my face, ask where Joe Varnell is; that’s me.

I’ve had several rookie teams ask “What should I expect at the competition?” Here are a few things to think about beforehand:

  1. Make sure you bring safety glasses and gloves. All the competitions are fairly strict on wearing safety glasses in the pits.
  2. Be prepared to work on or fix your robot! Bring tools, tie wraps, extra parts in case your robot breaks, duct tape (which is good for everything)
  3. One good idea is to bring ice chests with food for lunch. A lot of teams will be outside having lunch and relaxing during lunch. It’s also cheaper that way.
  4. Read the rules on what to bring. You’ll need a bill of goods, a list of items on your robot that didn’t come out of that years kit.
  5. Bring a long Ethernet cord. They don’t allow wireless communication in the pits so you need to tether your robot in the pits.
  6. Be prepared to keep your batteries that you are not using on the charger. This is so you can have a fresh battery for every match.
  7. Have a banner to display your team number, team mascot, and your sponsors. You should always support your sponsors.

At the competition, on Thursday, be prepared for:

  1. Robot weight in. After you get your robot unpacked and put together you’ll need to get it weighed in and sized. The weight is without the battery or bumpers.
  2. Access point setup. You’ll have to take you white access point off your robot to be setup with the WPA for the competition. This is so it will communicate properly with the Field Control System (FCS)
  3. Robot inspection. Robot inspectors will come around to your pit and verify your robot meets the spec’s from the robot manual. Some of the top things they check are bumper height and that they meet bumper specifications. Also, the pneumatic pressure is 120 psi max on the storage tank side and 60 psi on the solenoid side (make sure you read the pneumatics manual). The electronics power will be checked and probably that the driver station shows the battery voltage. (this is done by powering the analog bumper and putting a jumper on it)
  4. Try to get out on the field for a practice match. This will let you see how matches are run and what to expect.
  5. Don’t be afraid to ask for help. This is important. If you’re having problems, don’t struggle to long. Ask a more experienced team, mainly those with numbers under about 3000 or teams with robots that look really well put together. Also, there will probably be some experts there who can help the teams.
  6. There will also be a practice field somewhere to test your robots operation.
  7. There will also be a machine shop in case you need parts worked on.

On Friday and on Saturday morning are the qualifying rounds.

  1. Be prepared to answer the judge’s questions. There will be judges in blue shirts walking around asking questions. They are judging various categories and there should be students around (except during matches) to answer questions.
  2. Get your robot to the robot queue when it’s called. Look at the match schedule and see about when your matches are. Also, listen for your team number to be announced and get to the field quickly.
  3. Make sure you have time to look around and to watch other teams. This will give you ideas for next year.
  4. Talk to the veteran teams and make friends with them. The next year you can probably go out to other teams and see how they operate.
  5. Before your matches, talk with the other teams you have alliances with. Be a team player and plan your strategy. Learn each of the alliances robots strengths and weaknesses and plan what each team should be doing.
  6. Because of the random alliance parings, even rookie teams have a chance to be in the finals.

Saturday afternoon are the finals.

  1. The top 8 teams will be picking alliance partners, be prepared to pick just in case you make it to the finals. If you are choosing alliance partners and don’t know who to choose, the team rankings will be on the screen (probably behind you). Look at that and pick the top numbered team on the list.
  2. The rules of how to alliance pick will be explained. However, if you don’t understand then ask someone.
  3. If you are in the finals, have fresh batteries ready to go. Make sure your batteries are charged. The finials are fast paced.

I’ve probably left out some things and I apologize for that. There will be a lot going on, don’t let it overwhelm you.

In a nutshell, this is what will go on. My closing advice is to get plenty of sleep, be friendly, eat breakfast, talk to other teams, and, above all, HAVE FUN! It will be hardest fun you’ve ever had.

13
Feb
11

Mentoring and using LabVIEW and Joystick buttons

First I want to share the FIRST in Texas blog on FIRST mentoring. I’m very dedicated to FIRST and helping kids learn about Science, Technology, and Robotics. I also have a lot of fun mentoring and blessed to be able to help.

Next, it’s drawing near the end of the robot build season and time is getting tight. I’m hoping everyone is getting close to getting done or at least has a plan on getting done. With most teams, as in real engineering, the programming is getting done last. Even though the programming is getting done last you still need to test it before you get to the events.

One thing that I’ve found very useful is a way to hit and release a button and cause an action. Then later hit and release the same button and cause the opposite action. For instance, you hit the button to close the grabber and the same button to open the same grabber. Below is one way to do it, using button 8 of the joystick to control a solenoid. All the figures below are the same while loop showing the different case structure code.

Figure 1 is the diagram for the case where the button is still pressed after the processing has happened. The case structure is true when the button is pressed and the last time through the processing the button was also pressed.

Figure 1

Figure 2 below is when the button is not pressed. The result is false and no processing is done. The button is not pressed AND the last time through the processing the button was not pressed.

Figure 2

In figure 3 below, the button has been pressed and it’s first time through the loop to do the operation. This shows the processing when button was pressed AND last time through the processing the button was not pressed. This is when the actual operation is done. The innermost case statement is where the solenoid operation is done. In this case the last operation on the solenoid was turned on and the operation had been set to true. In the inner case statement it’s set to false this time so that next time the solenoid will be set opposite it currently is.

Figure 3

The false case of the innermost case statement would be opposite of figure 3, the solenoid would be turned on and a TRUE sent out. Also, the joystick and solenoid would need to be initialized in the begin.vi.

This vi would allow the opposite operation be done each time the button is pressed. There may be easier ways to do this by the NI folks, but this is the solution I came up with. I hope this helps.