The Playing Field

[Administrator]

Answers to your questions about the Playing Field will be posted to this thread.

[Professor Proton]

I went to Home Depot and Lowes today and Sonotube are sold in 2 slight different dimensions- The 8-inch tubes fit inside of each other so that they stack in the store inside each other. I assume that either tube is okay- the inside diameter is off by about 1/2 inch. Is this a safe assumption.

Yes, all of the Sonotubes labeled as 8-inch size are acceptable.

[Wil Wheaton]

2.4.5 <G15> states - "Field and field element tolerances may vary by as much as +/-1.0" (2.54cm). Teams must design their Robots accordingly.

Several instances within the field Complete Build Guide, the term Critical Dimension appears with a red lightning bolt. Does the +/-1.0" tolerance apply to these Critical Dimensions? If not, what is the acceptible tollerance for these Critical Dimensions? Perhaps we need a <G16> for clarification.

Also, does the +/-1.0" tollerance apply to any non-field elements? Things like the 18" robot sizing box.

A1: The tolerances are as indicated in <G15>. The critical dimensions in the building guide are to make sure that the field is as accurate as possible. During match play, elements (and sometimes the field walls) move. It would be a good idea to design your team's robot to be tolerant of variations in the field.

A2: No. The +/- 1.0" only applies to the field and field elements.

[Wil Wheaton]

When looking through the manual, it was talking about the magnet balls, but it never specifies their weight. What would the weight of the magnet balls be, and would it vary? If it does vary, how much would it vary by?

A: based in quick measurements, the magnet appears to add approximately 0.12 oz to the weight of the ball.

[Sheldon]

Is there any possibility of acquiring (or learning how to make) a magnet ball. We know that the regular balls are just normal raquetballs, but what strength, size, etc. magnet would be inside of it? Is there a way to either recreate one or borrow one pre-tournament?

A: The type of magnet used in the magnet ball can be found in the BOM which can be downloaded from the FIRST website http://usfirst.org/sites/default/fil...v_10172011.pdf

To make a magnet ball a ~1inch long slit is made in the racquet ball and the magnet is slipped inside. The slit is then glued back together with super glue.

[Professor Proton]

Hi Technic does not sell a IR slave beacon. We are building a competition field. Can we just use 2 stand alone IR beacons (FTCBCN)?
Thank you.

Yes, two HiTechnic Master IR Beacons can be used in place of the Master and Slave IR Beacon setup.