Troubleshootings for mBot Ranger

1. What can we do to verify if the Me Auriga hardware is normal while we encountering firmware update failure.

  1. Try restart the robot, replug the USB cable and update the firmware again, do not move the robot while in firmware updating;
  2. Download the Arduino IDE tools(link: to test the Me Auriga mainboard:
    • using USB cable to connect the Ranger with PC 
    • open IDE tool and click 'File'-->'Examples'-->'01.Basics'-->'Blink'


  • Select 'Tools'-->'Processor'-->'ATmega2560(Mega 2560)', and the USB port connecting with Me Auriga


  • Click '→' and wait for the result, if there's 'content mismatch' error message, it means the bootloader of Me Auriga was missing.



2. Why did the robot not work after I turned it on?

There may be two possible causes:

  • The batteries ran too low to power the robot. Replace the batteries with new ones.

  • The connection cables of the motors may be damaged. Replace the connection cables with new ones.


3. I try to turn the robot to the left but it turn to the right.

You may have connected the two motors to the wrong ports. Swap the ports of the two motors.


4. There were noises after I got the robot tank running.

  • Check the installation of the driving and driven wheels. Make sure that they are properly fitted.
  • Grease the bearings of the driven wheels.

5. The Nervous Bird couldn't work properly.

There may be two possible causes:

  • The batteries ran too low to power the robot. Replace the batteries with new ones.

  • The robot wasn't properly built. Make sure that all the wheels are properly fitted and no obstacle affects its movement.

See Playing mBot Ranger with the Makeblock App to learn how to control Nervous Bird.


6. I can’t connect the Makeblock app with the robot via Bluetooth.

  • Make sure that the Bluetooth on your smart device works properly.
  • Try restarting the app or resetting the main control board.
  • Tap the search icon to search for devices manually.
  • The batteries may run low. Try replacing the batteries with new ones.


7. Why can't I read the values of the ultrasonic sensor and line follower sensor?

Check the wiring of the sensors. Make sure that they are connected to the correct ports as described in the user manual or programs.


8. Why did the light sensor show a high value in a dark area?

Check whether the RGB LED is turned on. If yes, it may affect the sensing of the light sensor.


9. Why can't the line follower sensor detect black lines?

  • The line follower sensor is affected by the sunlight. Do not placr the sensor under the sun.
  • The distance between the the sensor and the line exceeds the detection range, which is 1 to 2 cm. Make sure that the black line is within the detection range.

10. Why the Ranger cannot avoid objects in object avoidance mode?

  1. Check wiring. The default setting for Ranger object avoidance mode is that the ultrasonic sensor connects to Port 10 on Auriga port.
  2. Download and install the latest version mBlock software, then reset default program for Ranger.
  3. Test if the Ultrasonic sensor is defective.

How to test if the ultrasonic sensor is defective?

  1. Download and install the latest version of Makeblock software on your PC. If you have a Mac, then you also need to install a driver.
  2. Connect Ranger with PC via USB.
  3. Make sure the ultrasonic module is connected to Port 10 (required). You should feel a slight click when the RJ 25 cable is properly inserted.
  4. Check whether the red indicator of the ultrasonic module is on. If not, the problem is caused by wiring.
  5. Upgrade firmware. Please refer to FAQ: How to Upgrade Firmware for Ranger”.
  6. Try to run this program, and move your hand in front of the ultrasonic sensor.     


  1. If the panda doesn't say an ever-changing number, try to change another RJ 25 cable to connect the ultrasonic sensor and the Port 9. Then try to repeat the above instruction 3-6.
  2. If the step 8 doesn't work for you either, attach the RJ25 cable with the ultrasonic sensor with port 8. Then try to run the program example, but choose "ultrasonic sensor Port 8 distance" this time.
  3. If the panda does say ever-changing number, please reset default program for Ranger, then try the obstacle avoidance mode again.

If the ultrasonic sensor doesn’t work on the above program, please contact


11. Why does the firmware upgrade failed


  1. Select the wrong board.

Please select the corresponding board then upgrade firmware or reset default program.


  1. The upload failed issue might cause by using defective modules, faulty serial port chip, or faulty Auriga board.
  • Please remove all the modules from Auriga, including RJ 25 cables, then upgrade firmware again. If the firmware is upload finished, which shows the issue is caused by one of the module. We could find out which module is faulty by test it on Auriga one by one.
  • If it is still the same issue, upload “Blink” program on Arduino IDE environment. If the program upload failed, which shows that the Auriga lost bootloader.
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