Problem with Remote control and brushless motors

Other Hardware Motors, Mechanics, Power and CNC
1

Hi all ,

I wrote a simple code to read the pulses from the receiver and control the brushless motors for a quad-copter but it`s not running as expected .

the code :-

#include<Servo.h>
 int ch[6] ;
 Servo br[5] ;
void setup() {
  for ( int i=1 ; i<=5 ; i++ )
  pinMode(i, INPUT);                                 // Channels pins
}
void loop() {
   for ( int i=1; i<=5; i++ )
  {
  ch[i] = pulseIn(i, HIGH  );                          // Read the pulse width of all channels
  }
  if ( ch[5]<=1200 )                                 // DISARM
  {
    for ( int n=1 ; n<=4 ; n++ )
    {
    br[n].write(0);
    br[n].detach();
    }
  }
  if ( ch[3]<=1200 && ch[4]>=1200 )                   // ARM
  {
   br[1].attach(8);
   br[2].attach(9);
   br[3].attach(10);
   br[4].attach(11);
   for ( int m=1 ; m<=4 ; m++ )
   {
     br[m].write(20);
   }
   delay(3000);
  }
  
  for ( int s=1 ; s<=5 ; s++ )                          // map channels        
   {
     ch[s]= map( ch[s] , 1100 , 1920 , 0 , 180 );
   }
  if ( ch[3]>20 )                                      // Throttle
  {
    for ( int s=0 ; s<=4  ; s++ )
    {
      br[s].write(ch[3]) ;
    }
  }  
  if ( ch[2]<90 )                                     // Roll
  {
  br[2].write((ch[3]-(ch[3]-ch[2])));
  br[4].write((ch[3]+(ch[3]-ch[2]))) ;  
}
if ( ch[2]>90 )
{
  br[4].write((ch[3]-(ch[3]-ch[2])));
  br[2].write((ch[3]+(ch[3]-ch[2]))) ;
}          
 if ( ch[1]<90 )                                       //Pitch
  {
  br[1].write((ch[3]-(ch[3]-ch[2])));
  
  br[3].write((ch[3]+(ch[3]-ch[2]))) ;  
}
if ( ch[1]>90 )
{
  br[3].write((ch[3]-(ch[3]-ch[2])));
  br[1].write((ch[3]+(ch[3]-ch[2]))) ;
}
}

The result is the that motors have random inputs and got random speeds !! i made sure all my connections are 100% correct .

then i wrote another code :-

#include <Servo.h>
Servo br11 , br9 ;
int ch3 ;
void setup ()
{
  br11.attach(11) ;
  br9.attach(9)   ;
  br11.write(20) ;
  br9.write(20) ;
  pinMode( 3 , INPUT ) ;  // channel pin
  delay(4000) ;
}
void loop ()
{
  ch3 = pulseIn( 3 , HIGH  ) ;           // read the channel signal 
  ch3 = map( ch3 , 1000 , 2000 , 0 , 180 ) ;
  br11.write(ch3) ;
  br9.write(ch3);  
}

and the result is that the 2 motors spin fast depending on ch3 value , slow down , then fast again , and slow down again and keeps doing this ! it seems like the pulseIn function have problems with .write function as when i remove the pulseIn function and control the motor using arduino only, it moves normally with the selected speed !
i made sure all connections are correct , batteries are fully charged , tested every motor alone without connecting the receiver to arduino ..... etc .
can anyone please tell me the problem and how can i fix it !

Thank you

2

Is it possible to log some of the values to the serial monitor as it runs? Then you can check if pulseIn is returning
what you expect, and whether running the motors is causing interference (a possibility). Keeping all the servo cables well
away from high-current cabling is important BTW.

3

Thanks alot for your response :slight_smile: yes the pulseIn() returns the expected value as i used the serial method in my trials before but the problem is motors receives the correct speed and runs at the correct speed then slow down after 2 sec. and runs fast again and it keeps doing this!
One of my trials was to change the default time in the pulseIn function and nothing changed until i changed it to 6500 to be x= pulseIn( 3,HIGH,6500 );
( i tried this in the 2nd code in my previous comment ) and the motors runs at the correct speed with no slow down !! so, i suspect that the problem is in the PulseIn function .
is the code written in my previous comment correct ! or it has some errors that causes this problem !

4

any one can help me please !