How to convert brushed flight controller to brushless


#21

Derp. I saw gate, typed gated, brain was thinking drain. Nvm


#22

Are you sure the gate runs at battery voltage? Generally MOSFET’s gate pin is isolated from source/drain and is switched at whatever the controlling chip is running at, unless it has a voltage level conversion chip between controller and MOSFET.

That said, I haven’t inspected many FCs looking for this.


#23

Fixed. Facepalm.


#24

missing one commentary of yours? Typed gated where?:smile:


#25

Sorry for the delay, I have been away, if you are using a pdb then yes + & - on the pdb, the esc’s get battery power either from the pdb or directly from the battery it depends on your set up, a pdb just distributes the power and puts it closer to where you need it.


#26

thks once more!


#27

Sorry to insist, but I think you were writing something about Gate and Drain but it disappeared!:smile:


#28

I had accidentally swapped terms in my head, the resulting response was wrong, so I deleted it. Nothing to add.


#29

thks for your contribution!


#30

Have you gotten your brushless motors to work on this board?


#31

As my soldering skills are bad I damaged my board. The new one is arriving Monday or Tuesday! Anyway there is an Indonesian guy that has already made a semi-conversion! He already flies with brushless motors but he must have the brushed motors also connected (and spinning). The challenge now is to remove these last motors!


#32

any result on your hubsan brushless conversion?


#33

Hi, I gave priority to 2 different builds , one of them linked somehow to this project (the brushless motors I had for the conversion project were assigned to it) that can be seen in a week or two.

But I still have a spare motor to test the conversion but not sure if it is ok after so many tests!

Enviado do Outlookhttp://aka.ms/weboutlook


#34

Hello all :slight_smile: i am attempting something similar myself , although with a little variation as i want to run 2 servos as well as a motor , i have so far had reasonable success , i have gotten the esc/brushless motor to work and the servos within Betaflight but so far am unable to have them working whilst outside ie powered by the battery.
These are the 3 boards i am attempting to use , the first and third boards have a built in Flysky receiver



So far i have been able to get it mostly working correctly , however for some reason no matter what i do the boards will always power the motor on and the motor will always be at full throttle and using the slider in the Motors Tab of Betaflight reduces the motors speed ( rather than increasing it ) however never to the point the motor is off. I have tried PWM, Brushed settings , reversed the motors polarity , tried reassigning the motors output incase i had a faulty output etc etc.

Any help would be appreciated.

scouse


#35

Go in your esc blheli suite and try inverting the incoming signal. Not sure exactly what the setting is called but that should fix it. Escs by default decode the signal based on when the signal is low. Always low (100% duty cycle) means full throttle and always high means low throttle. If you are grabbing your input signal for the escs off the mosfet with a resistor across the pads … your signal is inverted. You just need to tell the escs to listen to the other part of the square wave.


#36

Hi, thanks for the quick reply, sorry i shouldve been more precise.
On the board with the built in Flysky receiver : i have it set as “flying wing” as the mixer in Betaflight, i have assigned A00 and A01 as motors 1 and 2 and A02 - A03 as servos. The servos work correctly and in the gui everything moves as it should, but when i connect a brushed motor to positions 1 or 2 they start as though throttle is full and then increasing throttle using the slider the motors rpm will start to reduce until approx half way (1500) were they stay at a constant speed. The fets and resistors on that side of the board are untouched and reverting the firmware back to a QuadX and brushed setup brings everything back to working as it should.
The second board is pretty much the same except when a brushless esc is connected to the motor outputs it responds as it should ie waits to be armed before initializing throttle but connecting a brushed motor the motor start spinning.
The simple answer is of course to just use the brushless esc but while i am just experimenting i wanted to test with a brushed motor. I will video the boards in question tomorrow and post the video to see if there is anything glaring at me that i am missing.
I thought it was going to be the servos that gave me a headache lol they were the easiest part to complete.
Thank you for your help
Scouse