[Paparazzi-devel] Reply to: "ESC Startup"

[Chris]

Hi.
As i have constructed many paparazzi based UAVs i would say that for 
small UAVs you need a 2A 5v and a 1A or 2A 3.3 v smps capable of at 
least 18v or better 24v input.
Somehow the best efficiency always occures at just above 18v as it 
requires at least a 5 or 6 cell lipo.
For bigger UAVs where the primary battery pack's voltage is well above 
24V i found that i need at least
one 42V input 12V 3A output smps to power the paparazzi autopilot and 
perhaps the video transmitter along with the usual 5 and 3.3 V smps.
You could also offer an optional smps board as an accessory for the big 
guys :-)
I am just presenting some options here as many will prefer to use a 
second 12v lipo pack for powering the autopilot, camera and the servos 
through a 5A 5v BEC.
For the ESC you just need to make sure that during power up of the 
autopilot the signal to the ESC is 1000ms as 100% of the ESC i know take 
this value as  0% throttle.
It does not matter if the signal comes a little later after power is 
applied as the ESC will not arm
until it  sees a valid servo PWM signal.
By Esc calibration you probably mean the feature some ESC (castle 
creations) have where you need to leave the stick at full throttle for 
at least 3 seconds so the ESC can find out the minimum and maximum PWM 
values and use those for  maximum stick movement resolution.
Many other ESC employ a different method where you set the max and min 
PWM values by using
programming software.
Chris