Help me in my quadcopter

univbiskra · February 16, 2015, 7:42am

hello

my project is small quadcopter using 8 small coreless motors without ESC

motors http://www.ebay.com/itm/251743556401?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Voltage: 3.7 V

Current: the empty set: 0.08 A

Stalling: 1.8 A

Speed: 52000 RPM (the actual speed may be high or low)

Voltage: 4.2 V

Current: the empty set: 0.1 A

Stalling: 2 A

Speed: 60000 RPM (actual speed may be high or low)

motor driver TB6612FNG pololu dual motor driver https://www.pololu.com/product/713/specs

Continuous output current per channel:	1 A
Peak output current per channel:	3 A
Continuous paralleled output current:	2 A
Maximum PWM frequency:	100 kHz

arduino nano v3

battery 3.7 v 1000mah (motor power)

I made a test to know what max current can out from TB6612FNG(thoricly 2 amp) ,

I did that by changing PWM from 0 to 255 ,

I was expect that the current requested from motor should be 2 amp (max current) when the PWM in 255

but I found in my multimeter only 0.4 amp !!!! why
is the frequency of PWM can change the current out ?

This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/help-me-in-my-quadcopter

markusb · February 16, 2015, 8:27am

A robot project shouldn’t

A robot project shouldn’t have the headline ‘help me with my quadcopter’. Move it to the forum please and start a robot project after you have internalized the basics.

dangerousthing · February 16, 2015, 8:36am

The PWN just changes the
The PWN just changes the number of pulses per unit of time (OddBot has a great tutorial on this). At 0, then there would be no pulses sent to the motor, and at 255, the motor is on for the full time.

So the PWN effectively changes the voltage from zero to the maximum.

You should only get the maximum current when the motor is stalled.

I am worried, however that you motor driver may be not good enough. I’ve never tried a quad coppor, just rolling robots, so I may be wrong here. For a rolling robot you need a motor driver that can handle stall current for a long time period. The peak current is usually for just a very short time period.

I would think that for your motors you would need a 2A continuous current per channel.

univbiskra · February 16, 2015, 9:19am

I am not asked aboud PWM but

I am not asked aboud PWM but I mean

Changing in PWM frequencies on Arduino controllers

//---------------------------------------------- Set PWM frequency for D5 & D6 -------------------------------

  

//TCCR0B = TCCR0B & B11111000 | B00000001;    // set timer 0 divisor to     1 for PWM frequency of 62500.00 Hz

//TCCR0B = TCCR0B & B11111000 | B00000010;    // set timer 0 divisor to     8 for PWM frequency of  7812.50 Hz

  TCCR0B = TCCR0B & B11111000 | B00000011;    // set timer 0 divisor to    64 for PWM frequency of   976.56 Hz

//TCCR0B = TCCR0B & B11111000 | B00000100;    // set timer 0 divisor to   256 for PWM frequency of   244.14 Hz

//TCCR0B = TCCR0B & B11111000 | B00000101;    // set timer 0 divisor to  1024 for PWM frequency of    61.04 Hz

what means

Continuous paralleled output current: 2A

univbiskra · February 16, 2015, 9:24am

I am not asked aboud PWM but

I am not asked aboud PWM but I mean

Changing in PWM frequencies on Arduino controllers

//---------------------------------------------- Set PWM frequency for D5 & D6 -------------------------------

  

//TCCR0B = TCCR0B & B11111000 | B00000001;    // set timer 0 divisor to     1 for PWM frequency of 62500.00 Hz

//TCCR0B = TCCR0B & B11111000 | B00000010;    // set timer 0 divisor to     8 for PWM frequency of  7812.50 Hz

  TCCR0B = TCCR0B & B11111000 | B00000011;    // set timer 0 divisor to    64 for PWM frequency of   976.56 Hz

//TCCR0B = TCCR0B & B11111000 | B00000100;    // set timer 0 divisor to   256 for PWM frequency of   244.14 Hz

//TCCR0B = TCCR0B & B11111000 | B00000101;    // set timer 0 divisor to  1024 for PWM frequency of    61.04 Hz

what means

Continuous paralleled output current: 2A

markusb · February 16, 2015, 9:25am

1+1=2. And now move that

1+1=2. And now move that post to the forum. This isn’t a robot project!

univbiskra · February 16, 2015, 3:39pm

I sent you a private

I sent you a private message

I asked you about how can I move this … because I didn’t know how I do that

I asking you again is there an option to move it ???

I hope 1+1 become 1-1=0

sir_pumpkinhead · February 19, 2015, 7:40pm

Being picky

I hate to be that guy but if you are using 8 motors then its an octocopter, not a quadcopter.

Good luck with your project

(sorry i couldn’t provide any actuall help)