Home depot has different sized sheets Richard.

LOL... I used to work part time for the depot... I know very well that they sell Lexan sheets... Problem is, they don't sell round Lexan or poly carbonate....

Build a robot that can hold a laser cutter or dremel, get the robot to cut it to a perfect circle, that wouldn't be too difficult to do with a little EZ-Script

@Rich... What's the formula....? Pi r2 something, something?..... Sounds like some serious math.... I think I might be able to do it free hand...

I think there is an example in the examples for a circle.

Easy way though... secure a modified servo to the centre of the sheet. Build an arm the correct radius with the cutting device on the end of it, let the modified servo spin around. No maths needed (I'm currently designing something similar using EZ-Bits)

Now, If I happened to wire the connector wrong, is the Roomba safe? or would the Roomba go "caput"?

And to do the voltage check(outlined here:Roomba Hardware)I would put the voltmeter on the signal and the gnd on the wire?

Yes, you must be careful when wiring the 7 pin min din leads. The full battery potential is present on several pins. Look at this picture for guidance.