I may be able to shed a little light on the arming sequence for the Turnigy series ECS's. Prelude- I'm a total noob with my arduino, having just decided to move into UAV's, yet I'm an avid RC pilot.
Most all esc's I've come across need the first signal to be the max setting (full throttle) then after a signaling beep quickly reduce throttle to zero to arm it or the unit may jump into its 'programming mode'. This step only needs to be done when a new combination of parts is assembled, or a change was made somewhere in the line.(i.e. new rx or tx or motor even)
After the first initialization the esc can and should be habitually started at 20% throttle thus requiring only to be set to zero to arm. But booting at 0% is possible, its just ready to go immediately there after. Not a good thing to have a .01 to 2kw motor swinging a set of knifes that only a minor bump of a lever would set in motion.
The $9 programming card is the only way to go imo, plus you can change the arming tones to any number of common tunes ;D