2014-09-21

DIY drone - tutorial for developers | Part 9 - Calibrating your ESCs and fix the throttle

Connect your ESCs to the FC.

Again, be careful and connect the signal wires (white) on the inside.

You should use 2, 3, 5, and 6.


They should match those numbers for the motors :


** do not mount any propeller on the motors **
I don't say that because I consider you a 5 yo but because the motors might go full throttle during the calibration if the ESC doesn't catch up the calibration signal and really hurt you. It happened to me with the propellers off so it happens don't do it.

Go to your config.h, uncomment the symbol : ESC_CALIB_CANNOT_FLY (here)

Build and flash.

Disconnect all power (USB / battery) then connect the battery.

The 4 ESCs should make a triple beep, then a long beep. Done, your ESCs are calibrated for the inputs the FC will give them. Disconnect the battery.

Rebuild a normal firmware (with the ESC_CALIB_CANNOT_FLY commented out), and reflash.

Reconnect the battery.

Now you need to learn how to arm / disarm your quadcopter.

There is a security to prevent you from accidentally powering up your quadcopter.

You can arm your quadcopter doing this :



You should see the leds A and C on the FC switching to solid ON.

Now you should be able to play with the throttle on your TX and see how it reacts (still props off).

Ideally the motors should be off at minimum throttle and start off slowly once you push it up.

Once you want to check out a setting or do something else, don't forget to disarm it :


The leds A and C should be off when it is disarmed.

A last settings you need to fiddle with is the MIN_THROTTLE and MIN_COMMAND.

This is in the Misc Menu and/or config.h :


Note: here there is a trick you have to click to the upload arrow once you have change anything otherwise it won't be taken into account (yeah it took me 3 or 4 tries to figure that out !)


Remember the motors are actually compatible with the input from the RX. But here you can change the RX values Multiwii will emulate for you.

The motors won't run if the throttle is too low, to preserve a full resolution you need to find the minimum value of MinThrottle that you can have where the motors will start to rotate when you just started to push the throttle. Try to dychotomize it to its perfect value.

MinCommand is the level Multiwii will send to the ESC when you disarm it. It has to be a safe value you are sure no motor will rotate.

You are almost ready to fly your quadcopter !