i need a sketch on my arduino uno to start exactly five seconds after i turn on the power.
I think the easiest way is going to be to put delay(5000) at the first line of setup. You can of course tweak it for the bootloader delay, I can't remember where I saw it, but I think it's documented on the Arduino reference somewhere.
as accurate as possible. i'm competing in a sumo bot competition and there is a five second delay before starting.if i start too early i'm disqualified.if i start a second late the other bot has a jump on me.