2014-09-21

DIY drone - tutorial for developers | Part 7 - Motors + ESCs setup and test

Charging up a battery

It is a 3S which means 3 elements of 3.7 volts adding up to 11.1v.
When you'll charge it up through the little connector, you'll see that the charger will show you the state of those 3 sub-batteries one by one and charge them up :


Then it will show the total charge: 


Note: don't put that to charge during the night and forget it, it will beep like crazy at the end of the charge.

Trying your motors directly 

What you need to understand is that your RX (receiver) and ESCs are originally made to work directly together in the classical RC world.

So you can try them out !

Here is the overview :


Always start with no power and connect the battery at the very end !
  1. connect the 3 outputs of the ESC to a motor
  2. connect the ESC to the RX. Be careful, the signal wire (white) on the inside.
    like this :



It is connected on the THRO (throttle) input. The ESC will power the RX.
Be sure your TX throttle is at 0.

Check the polarity of the ESC power, connect black with black, CHECK IT AGAIN OR IT MIGHT BLOW UP AT YOUR FACE IF YOU DON'T. Connect black with black, CHECK AGAIN.
Connect red with red.

You'll hear your ESC beeping, it is normal as they initialize then wonder why they have no input.

Switch on your TX.

The RX should stop blinking, telling you that it paired correctly with the TX.

Play with the throttle to see if the ESC and Motor work correctly.

Take this opportunity to be sure you are in this configuration :



If a motor is reversed, don't panic, swap 2 of the 3 outputs from the ESC and it should start to turn to the other side.

Check your 4 motors and ESC to be sure everything is fine before complicating the system.

Now the ESCs are for anything : cars, boats, propeller hats etc... they are not tuned by default to be for a quadcopter.

Instead of your RX, connect one to the ESC programming card THEN power it up.
Again, be extra careful about all the polarities : be sure that you have connected the signal wire on the right side on the programming card.

The card will switch the ESC into programming mode and will show the factory parameters they have, mine arrived like this :



Play with the little controls at the bottom until it looks like that :


And press ok to push the configuration.

That 4 times, don't be impatient otherwise you'll fry something.

Once everything is tested, you can attach your ESC to the arms of the frame (underneath is better to leave some clearance to the propellers) :


then mount the power bus on the frame. I opened up the bottom and enclosed the power bus inside :



You can then do an integration test with the power bus : 
(hooking the RX to the ESC one by one)


Check the conductivity everywhere between different points of the power bus before that with your multimeter, also check if there is absolutely no conductivity between reds and blacks.

The low level stuff is done, let's take care of the mid level stuff, the flight controller (FC).