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APM 2.5 ArduCopter - Quad change output channel 4 to another output channel

Posted by Mike Clancy on April 20, 2013 at 1:34am

Hi All,

I have a quick question and was hoping someone could kindly point me into the right direction. My APM 2.5 had a damaged contact on the microprocessor that is connected to output channel 4. Since I'm only using 4 channels on my quad, I was hoping to change the output on channel 4 to either channel 5,6,7, or 8.

I have downloaded the ArduCopter 2.9.1 branch from GitHub and can successfully compile the firmware. I have tried changing the output definition on ../libraries/APM_RC/APM_RC.h

// Radio channels

// Note channels are from 0!

#define CH_1 0
#define CH_2 1
#define CH_3 2
#define CH_4 6
#define CH_5 4
#define CH_6 5
#define CH_7 3
#define CH_8 7
#define CH_9 8
#define CH_10 9
#define CH_11 10

I was hoping this would just swap the output on channel 4 and 7. Although now I do get a PWM throttle response from channel 7. The PWM is not consistant with the output of channel 1, 2, and 3.

If anyone could let me know what other code I must change to achieve this, I would greatly appreciate it.

Kind Regards,

Mike

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Replies

  • Stefano July 24, 2015 at 11:59pm
    hi, i'm a newbie. i think i have the same problem. In my flight controller the port number 2 is not working anymore. I'd like to use other free ports (i have a quadcopter) to control the motor. i'm looking inside the apm 3.2.1 version but i can't find the ap_motors.h you mentioned. do you know if the motor mapping is in another file? if i'll find it, how can i compile the firmware to install it in the drone? thanks
    • Tomasz Ściepłek > Stefano March 15, 2016 at 11:44pm

      Hi,

      I am also newbie, so I am not 100% sure my solution is correct, but it worked for me. 

      After quick look at sources I found out that set_motor_to_channel_map method was removed in this commit, so I checked two solutions and both worked. In my case chanel 4 was broken, so I swapped channel 4 with 5.

      Solution 1 (ArduCopter-3.2.1)

      In file ardupilot\libraries\AP_Motors\/AP_Motors_Class.h I made the following change:

       -#define APM2_MOTOR_TO_CHANNEL_MAP CH_1,CH_2,CH_3,CH_4,CH_5,CH_6,CH_7,CH_8
      +#define APM2_MOTOR_TO_CHANNEL_MAP CH_1,CH_2,CH_3,CH_5,CH_4,CH_6,CH_7,CH_8

      Solution 2 (ArduCopter-3.1.2)

      I simply checkout to version 3.1.2 (git checkout ArduCopter-3.1.2) and made the change suggested by Mike. Note that in this version method set_motor_to_channel_map can be found in file ardupilot\libraries\AP_Motors\/AP_Motors_Class.h (not in AP_Motors.h).

      Hope that helps.

  • Mike Clancy April 20, 2013 at 3:21am

    Hi All,

    Looks like I figured it out, so if anyone is ever curious:

    ../libraries/AP_Motors/AP_Motors.h

     // set mapping from motor number to RC channel
        virtual void        set_motor_to_channel_map( uint8_t mot_1, uint8_t mot_2, uint8_t mot_3, uint8_t mot_4, uint8_t mot_5, uint8_t mot_6, uint8_t mot_7, uint8_t mot_$
            _motor_to_channel_map[AP_MOTORS_MOT_1] = mot_1;
            _motor_to_channel_map[AP_MOTORS_MOT_2] = mot_2;
            _motor_to_channel_map[AP_MOTORS_MOT_3] = mot_3;
            _motor_to_channel_map[AP_MOTORS_MOT_5] = mot_4;
            _motor_to_channel_map[AP_MOTORS_MOT_4] = mot_5;
            _motor_to_channel_map[AP_MOTORS_MOT_6] = mot_6;
            _motor_to_channel_map[AP_MOTORS_MOT_7] = mot_7;
            _motor_to_channel_map[AP_MOTORS_MOT_8] = mot_8;
        }

    Just swapped MOTORS_MOT_5 and MOTORS_MOT_4 in the two bolded lines and motor 4 is now on channel 5.

    Kind Regards,

    Mike

    • Thiago Kern > Mike Clancy January 17, 2015 at 6:15pm

      Hi Mike! 

      Did found the solution for the newest firmwares? Because it seems that after the 2.9 version the code changed and the same tweak you've made cannot be done... 

      Regards! 

    • mhorban > Mike Clancy August 20, 2014 at 9:01am

      I have this same problem but no output on channel 2. So is there a way to edit the hex file directly or do I have to find the arduino file and compile (high I have no clue how to do?). I'm going crazy with this as I just got it together and after one programming blew the 3.3 regarding (which is now fixed) and this no output now. I'm running a hexacopter so I would have to swap to 7 or 8.

      Thanks!

    • Rahul Vyas > Mike Clancy April 23, 2014 at 3:02am

      Please buddy help me do this.
      I am getting these errors even without editing anything-
      I am having many errors in compiling the default firmware, here they are-

      compassmot.pde: In function 'uint8_t mavlink_compassmot(mavlink_channel_t)':
      compassmot:230: error: 'report_compass' was not declared in this scope
      crash_check.pde: In function 'void parachute_check()':
      crash_check.pde:113: warning: comparison between signed and unsigned integer expressions
      crash_check.pde: In function 'void parachute_manual_release()':
      crash_check.pde:180: warning: comparison between signed and unsigned integer expressions
      motors.pde: In function 'bool pre_arm_gps_checks(bool)':
      motors.pde:440: warning: comparison between signed and unsigned integer expressions
      radio.pde: In function 'void init_rc_out()':
      radio:75: error: 'init_esc' was not declared in this scope
      system.pde: In function 'void init_ardupilot()':
      system:127: error: 'report_version' was not declared in this scope
      /compat.h: At global scope:
      /compat.h:12: warning: 'void run_cli(AP_HAL::UARTDriver*)' declared 'static' but never defined
      ArduCopter.pde:175: warning: 'void update_optical_flow()' declared 'static' but never defined
      GCS_Mavlink.pde:284: warning: 'void send_simstate(mavlink_channel_t)' defined but not used
      ArduCopter.pde:219: warning: 'void send_servo_out(mavlink_channel_t)' declared 'static' but never defined
      Log.pde:248: warning: 'void Log_Write_Optflow()' defined but not used
      Log.pde:524: warning: 'void Log_Write_Data(uint8_t, int16_t)' defined but not used
      Log.pde:581: warning: 'void Log_Write_Data(uint8_t, uint32_t)' defined but not used
      Log.pde:600: warning: 'void Log_Write_Data(uint8_t, float)' defined but not used
      ArduCopter.pde:260: warning: 'void Log_Write_IMU()' declared 'static' but never defined
      ArduCopter.pde:261: warning: 'void Log_Write_GPS()' declared 'static' but never defined
      compat.pde:8: warning: 'void mavlink_delay(uint32_t)' defined but not used
      ArduCopter.pde:411: warning: 'void heli_init()' declared 'static' but never defined
      ArduCopter.pde:412: warning: 'int16_t get_pilot_desired_collective(int16_t)' declared 'static' but never defined
      ArduCopter.pde:413: warning: 'void check_dynamic_flight()' declared 'static' but never defined
      ArduCopter.pde:414: warning: 'void heli_update_landing_swash()' declared 'static' but never defined
      ArduCopter.pde:415: warning: 'void heli_update_rotor_speed_targets()' declared 'static' but never defined
      ArduCopter.pde:416: warning: 'bool heli_acro_init(bool)' declared 'static' but never defined
      ArduCopter.pde:417: warning: 'void heli_acro_run()' declared 'static' but never defined
      ArduCopter.pde:418: warning: 'bool heli_stabilize_init(bool)' declared 'static' but never defined
      ArduCopter.pde:419: warning: 'void heli_stabilize_run()' declared 'static' but never defined
      motors.pde:567: warning: 'void servo_write(uint8_t, uint16_t)' defined but not used
      ArduCopter.pde:472: warning: 'void print_hit_enter()' declared 'static' but never defined
      Log.pde:154: warning: 'int8_t process_logs(uint8_t, const Menu::arg*)' defined but not used

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