where does he say that?
im saying it would work, but would shorten the life
maybe 7.2V for the regulator
oops sorry it wasnt admin
anyway (quote): As far as I understand the 9V pin provides the same voltage as the input battery, so when you use the 6V battery
as input, the 9V pin will provide these 6V.
It should work, but not with a 6V battery. It needs at least 7.2V to properly power the Arduino board. Ok, here is why: there is a diode to prevent accidental power voltage swapping and the voltage regulator is not a Low Dropout. The voltage drop on the diode is 0.7V plus the voltage drop on the Vreg of 1.2V, makes almost 2 volts over the 5 volts of the output. That means 6V battery is out of the question. If you replace the diode with a wire and replace the Vreg with a Low Droput Vreg (like LM2940), then you can use a 6V battery to power the servos directly and the board.
But the servos should work at 7.2V. This is what I am using for my CD-bot. CD-bot is a $50 robot in a round CD case that I am building to test out code for pathfinding and object finding using an AVRcam.
PS: could i use any battery that matches my required voltage(7.2V) and has a large mAh?
but i have 3 servos do i still need the same voltage if i would use 1? and i have a IR sensor which woltage i dont know...do i have to use another battery for that? :S