Everything is calibrated but in the ground, when I give the motors throttle, one side seems to rotate stronger then other (I think the quadcopter is not perfectly balanced). If I give the motors a good throttle it will not be a problem, rigth? With him at the ground, I give a little throttle and at the GUI I can see 3 motors with the same value and 1 motor with less throttle. I think it should't happen because the quadcopter is on the ground and there's no need of motors corrections since it's perfectly aligned to the ground. I turned off baro and mag and the same happened to that motor. If I give a good throttle the quadcopter will fly without problems, correcting this problem, rigth?
Have you balanced the motor rpms by using the Tx trim switches and the GUI. Level mode off and throttle up to about 50% and then use Tx trim to get all the motor rpms approx the same (take props off for this). Flight test and adjust trims as needed to get hands off hover, even though you have trimmed the motor rpms you cannot trim for any variables in material densities motor friction and other stuff, that's why you trim again in flight. You will probably find that one motor might have more power at start than the others but they will soon catch up you know they will you have seen it in the GUI. Once you have it trimmed you can then set about level mode trim I use the passthrough in flight calibration in the code and find its a doddle to use. Just remember to remove Tx trim before you try to fly again http://ncopters.blogspot.de/2012/04/how ... on-in.html explains how to do it.
Even if motors are showing 1500 in the GUI it does not mean that they are producing the same power that can only be found through flight test.
Set Tx trims to middle position except throttle which should be all the way down, (not sure if the throttle trim to min is really needed but I do it anyway). You can play around with the trim to see what is does to your motors by just moving them from one extreme to the other. When you have finished playing just set them back to mid position.
Remove props, connect to GUI so you can see what is happening.
Power up copter and Tx start motors and set throttle to about 50%.
Look at the motor rpms on the GUI and if they are all the same then you dont need to touch Tx trims. If you have Quad + and one motor is lower or higher than the other on the opposite side then adjust trim on the TX for that motor so it brings it to the same rpm as the other, i.e if front motor is lower than rear motor then adjust PITCH trim to make both motors same rpm. As you move the trim to raise the low motor it will also reduce the rpm for the high motor. If the left and right motors are not the same then repeat process but with ROLL trim.
After this all your motor rpms should be approx the same value a test flight in acro (GYRO) only mode will confirm hands off hover if not adjust trims to get hands off hover.
When you have you copter flying like this you can set about trimming for stable mode. This is where the passthrough method comes in, it is quicker and easier that the old method of making lots of acc trim adjustments via the sticks then a test flight until it was trimmed in stable mode.
With the passthrough method you assign a switch on your Tx to toggle passthrough mode on or off as well as uncomment in flight calibration in the config.h. When you fly you get into a hover then flick the switch for passthrough on, land switch passthrough off and set Tx trims to mid position except throttle. When you switch the passthrough off it writes the settings it has collected inflight into the eeprom and stores them, that is it, your level mode is trimmed you should be able to flick acc on or off inflight and not notice any difference other than when it is on your copter will self level if you let go of the sticks. If you press calibrate acc anytime after this you will have to go through the passthrough trim again as calibration will clear the setting from the eeprom.
