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Old Jan 25, 2013, 09:08 PM
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can I convert a brushed motor to brushless

I made this question in a different area ., but not sure if i was understood or was asking in right area . have few questions and hope i will get the answer .

If i have a quad copter the cheep ones for $50 from china whatever brand ...etc they have small brushed motors ., however these motors go bad after a while.

can change the motor all 4 for example to different ones and the cycle continues., however, . if i want to install brush less small motors i have few small ones and i do have the control units for them .can i build a small circuit where i can go from the + and - wires for the brushed motor to the control unit for the brush less motor .
.,
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Old Jan 25, 2013, 10:47 PM
Life begins at transition
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A store-bought voltage - PWM converter (goes between the brushed ESC and the brushless ESC)
http://www.miracle-mart.com/store/in...oducts_id=3949

A thread doing similar things with a micro heli:
http://www.rcgroups.com/forums/showthread.php?t=1500927

If you can find a PWM for each brushed ESC somewhere (on the controller board, or between the controller and ESC if they're off-board), you can just feed that straight into the brushless ESC.
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Old Jan 26, 2013, 12:38 AM
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Originally Posted by Odysis View Post
A store-bought voltage - PWM converter (goes between the brushed ESC and the brushless ESC)
http://www.miracle-mart.com/store/in...oducts_id=3949
One thing to watch out for is that the brushless converter needs to have fast response. I tried using the Extreme converter to drive a brushless tail motor on my GWS Mini Dragonfly helicopter, but it was much much too slow and the gyro could not the tail steady. To fix this this I wrote my own firmware and loaded it into the converter.
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Old Jan 26, 2013, 12:50 AM
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Originally Posted by Bruce Abbott View Post
One thing to watch out for is that the brushless converter needs to have fast response. I tried using the Extreme converter to drive a brushless tail motor on my GWS Mini Dragonfly helicopter, but it was much much too slow and the gyro could not the tail steady. To fix this this I wrote my own firmware and loaded it into the converter.
fimware use ATMEGA48 ,you can convert to ATMEGA8 ?
it is compatible with many types of 4in1?

can show me the schematic? i do not understand connect input PWM with code

; Atmega48 with 16MHz ceramic resonator.
; LED on PC2 (pin 25), connected to GND via 1k resistor.
; Motor PWM input on PD6 (pin 10), low = motor on.
; Servo pulse output on PB1/OC1A (pin 13)
thanks Bruce abbot
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Old Jan 26, 2013, 12:57 PM
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as a start this great info.and thank you all indeed for the time and response.,
., so the link to the converter you say ., however there is a note on that site This converter is NOT suitable to use on Blade MCPX., i think the mcpx is something to what i will be doing .NO
, and according to the 2nd response by bruce it will work but too slow ., need to modify ?.
the IC on the converter is an Atmega of some model..., and needs to be replaced ,and program the new atmega with the code he wrote.??
if that is the case ,and worked for (bruce ) would you please provide me all information for to complete the project ..what IC do i need to modify the board ....etc

2.odysis is saying if i can tap into the the quadcopter board somewhere and feed the brushless controler... is that what he is saying ,?
if so. so i have to just do trial and error until i reach that pin on the board .., that is if there is a place to tap.
again for real nice work people . just need more and complete info to start the project.
sincerely
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Old Jan 26, 2013, 01:14 PM
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Some time ago I developed a direct motor-PWM to brushless software for a commercial ESC.

Here is the page:
http://home.versanet.de/~b-konze/blc_6a/blc_6a.htm

and this is the appropriate software:
http://home.versanet.de/~b-konze/blc...cp_pwm_r02.zip

It is important to feed in the motor signal in the right way. If you use more than one lipo, it is necessary to adapt the motor signal to input port of the atmega8.

quax
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Old Jan 26, 2013, 02:29 PM
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Quote:
Originally Posted by fantasy1988 View Post
fimware use ATMEGA48 ,you can convert to ATMEGA8?
Converting to ATMEGA8 should not be difficult.

Quote:
it is compatible with many types of 4in1?
Yes. It automatically adjusts to the incoming PWM frequency.

Quote:
can show me the schematic? i do not understand connect input PWM with code
The circuit is powered from the brushless ESC's BEC (via the throttle servo plug) but the PWM + input is connected to the original brushed motor's power supply. R3 and R4 reduce this voltage down to logic level, and are the correct values for 2S Lipo. If you are running 3S Lipo then the value of R3 should be increased to 2.2k Ohms (to keep the input voltage at pin 10 below 5V).

I just realized that the code on my website is out of date.
Here is the latest version.

***EDIT***

Found bug in V0.3 code - analog comparator's inverting input was being forced to ground (worked OK on the bench, but unstable in heli!) Now updated to V0.4. Also included hex files for ATmega48, and ATmega8 (untested).
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Last edited by Bruce Abbott; Jan 28, 2013 at 04:21 PM. Reason: Corrected circuit diagram, updated code to v0.4
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Old Jan 26, 2013, 03:06 PM
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This converter is NOT suitable to use on Blade MCPX.... according to the 2nd response by bruce it will work but too slow
Correct. Co-axial helis have gyro control of motor speed, and the stock Extreme converter is too slow for this use (it's fine for single rotor helis where main motor speed is controlled manually by the pilot).

Quote:
the IC on the converter is an Atmega of some model..., and needs to be replaced ,and program the new atmega with the code he wrote.??
The MCU does not have to be replaced - the existing one just has to be re-flashed (there are pads on the pcb for connecting to the programming pins - see picture below). Alternatively you could make your own board from scratch. You just need an ATMega48 chip, a 16MHz crystal or ceramic resonator, and a few resistors and capacitors.

Flashing your brushless ESC with quax's code is an is even simpler option (you just need to make the voltage divider to cut down the input voltage) but you can't go back to the ESC's original firmware, and it only works with ESC's that have an ATMega8.

Quote:
odysis is saying if i can tap into the the quadcopter board somewhere and feed the brushless controler... is that what he is saying ,?
if so. so i have to just do trial and error until i reach that pin on the board .., that is if there is a place to tap.
"cheap ones for $50 from china" probably do all their processing internally, and don't don't have any place to tap into.
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Last edited by Bruce Abbott; Jan 26, 2013 at 03:17 PM.
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Old Jan 26, 2013, 03:14 PM
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this is very exciting I love this. Thank you for all these great replies suggestions...etc
Bruce just to make it clear. I still need to buy Brushed to Brushless Signal Converter from the store, the link I was provided, and then replace the atmega on board with the atmega schematic the one you have placed here
Just by looking at the schematic you have provided ,it looks as a complete circuit board for the whole project ., has input output the whole thing, i do not see the rest of the control unit in there ...
don't need to buy any converter. Your schematic is complete working circuit ?? do i understand you right .? or im not as ok with electronics as i thought.

either or so know i need to look for a programmer or find the one i have or build one ., hey maybe buy the atmega too. please bare with me here
sincerely
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Last edited by electrontube; Jan 26, 2013 at 03:39 PM.
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Old Jan 26, 2013, 03:43 PM
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You can either buy the Extreme converter and modify it (connect pin 30 to pin 13) or get your own components and wire them according to my circuit.

The only other hardware you need is a programmer. I used a simple AVR isp parallel port programmer with PonyProg.
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Old Jan 26, 2013, 04:18 PM
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ok great as soon as I'm home in few I'm getting started and I'll keep you updated i know this will be great to see it working, i can modify my quadcopter to brushless , that is great.
I'll keep you updated sincerely
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Old Jan 26, 2013, 05:22 PM
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One more question if i may ask . i found few atmega 8and 128 in my junk collection . ...the old days when i used them., you are using atmega 48 .
the question can i use the atmega 8 or atmega 128 instead of the 48

... and of course your code was build for the 48 .ofcourse if they are the same great i dont need to wait a week to place an order .. shipping the order ..etc

if they all the same.? what do you need to change in the code so it will work with the atmega 8. or the 128 .

anyhow i want best results so if i need to buy i will buy the Atmega 48 i will buy few
sincerely
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Old Jan 26, 2013, 05:47 PM
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Now there all great idea's and do work.
Brushed controller > Converter >Brushless ESC > Brushless Motor
Used both options that Qaux made there great.
Tools
AVR's (mcu)
Programmer USBasp or printer port cheap (have used it without resistors but you shouldn't) Could even use Arduino as an Programmer

Other way
Brushed controller > Brushless ESC > Motor
This time using Silabs based ESC guessing you want small and cheap 2g esc

Tools
Arduino UNO or Arduino Mini Pro.
Cable

Software https://github.com/bitdump/BLHeli
Thread to help with problems http://www.helifreak.com/showthread.php?t=390517
Other thread for programmer / Setup software http://www.olliw.eu/2013/ardubox/

I'm doing a multiWii using 2g esc and 2g hexTronik
Ok the motor can be bad (buy extra) mostly because there so small and soldered cables do come apart but!! when you get that sorted using SSkaug code is a joy, Olliw inter face/ programmer makes changes super simple.
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Old Jan 26, 2013, 06:07 PM
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Quote:
Originally Posted by SadSack View Post
....
Software https://github.com/bitdump/BLHeli
Thread to help with problems http://www.helifreak.com/showthread.php?t=390517
Other thread for programmer / Setup software http://www.olliw.eu/2013/ardubox/
.....
SadSack, you are right, I also think that this is the best solution.
My software is somewhat "overaged"

BLHeli should be the choice.
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Old Jan 26, 2013, 06:24 PM
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don't say that I've still got 3 working Nano Fleas and 6amp modded ones takes a lot to burn them out.

You should check out v9.4. I can watch 2g motor very slowly start to spin and smooth speed change all the way to max . He's done a great job with it. I have rewinded one of my old ones for fun. None load speed 45000 rpm. I did swap out fets on esc there little bit slow but once done pretty rapid to respond
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