FAQs on mBot Mega

Electronic

Q1. The LED indicator of a sensor is on after mBot Mega is powered on, but the motor can't rotate, why?

Check whether the motors are properly connected. Make sure that they are properly connected to the motor drivers.

The other possible causes may be:

  • The battery power is low. In this case, replace the batteries with new ones.
  • The motor power value set during programming is too low. It is recommended to set a power value of more than 40%.

 


 

Q2. After I connect the RGB LED module and turn on mBot Mega, the RGB LED module is not lit up, why?

No power indicator is provided for the RGB LED module. If you want to see a power indication, you can write a program to light up the LEDs when it is powered on.

 


 

Q3. The sensors or RGB LED modules do not work properly, why?

The order of the pins may be wrong. Make sure that the 3 pins (GND, VCC, IN) of the module correspond to the PIN pins (GND, 5V, SIG) on MegaPi, respectively.
Another possible cause is that 
the electronic module is damaged.

 


 

Q4. The IR proximity sensor doesn't work, why?

The possible causes are described as follows:

  • The IR proximity sensor works by transmitting and receiving infrared light. If an obstacle absorbs infrared light, misjudgement is caused.
  • The value of the potentiometer on the sensor is set too low. Set it to be closer to the infrared transmitter.
  • The sensor is affected by other light sources, such as a strong light source or infrared light emitted by an infrared remote control.
  • The pins of the 3-pin cable are not connected in the expected sequence.

 

Q5. The line following function is not performed properly, why?

The possible causes are described as follows:

  • The signal wires of the left and right line following sensors are connected reversely.
  • The ground of the operating environment can't reflect infrared light, or the material of the black line can't absorb infrared.
  • The sensors are affected by other light sources, such as a strong light source or infrared light emitted by an infrared remote control.
  • The pins of the 3-pin cable are not connected in the expected sequence.
  • The sensors are too close to the ground. Pay attention to the installation position of the sensors.

 


 

Q6. The impact switch doesn't work, why?

The possible causes are described as follows:

  • The force for pressing the impact switch is not large enough. 
  • The pins of the 3-pin cable are not connected in the expected sequence.

 


 

Q7. How can I use other Makeblock electronic modules? 

You can connect mBot Mega to the RJ25 series electronic modules through a MegaPi RJ25 adapter. Note that mBot Mega is not compatible with mBuild and Neuron electronic modules.

 


 

Q8. Which electronic modules are compatible with mBot Mega? 

mBot Mega is compatible with most of 3-pin connectors, sensors that can work at 3.3V-5V, RGB LEDs and servos. 

 


 

 

Structure

Q1. After being tightened, the wheels shake when runing, why?

This may be caused by the gap in the motor shafts. The shaking may be more obvious when extended shafts are used.

Since the four Mecanum wheels are required to fully come in contact with the ground when they move,  you need to keep a certain movement space for the wheels in the vertical direction.

 


 

Q2. Why do I need to put nylon washers when installing electronic modules? 

If the metal parts of an electronic module are in direct contact with the metal shell of mBot Mega, a short circuit may be caused and the electronic module may be damaged.

 


 

Q3. A deviation occurs when mBot Mega moves in a straight line, why? 

The possible causes are described as follows:

  • The TT motors are common DC motors without encoder sensors. The four motors are not consistent with each other and therefore run at different speed.
  • The ground is rough and therefore the areas of the four wheels come in contact with the ground are different, and thus the friction between the wheels and the ground is different and a deviation is caused.

 


 

Q4. Noise is made when mBot Mega is moving, why?

There are 9 rollers on each Mecanum wheel. When moving at high speed, each roller      maked noise when it comes in contact with the ground.

 


 

Software

Q1. I can't use the default functions (gesture recognition, line following, and obstacle avoidance) after starting mBot Mega, why?

You need to update the firmware to the factory version before you use mBot Mega. For details about firmware update, see Updating the Firmware of mBot Mega.

 


 

Q2. Why does the previous program disappear after I update the firmware?

mBbot Mega can store only one program. Updating the firmware also restores the ex-factory program and therefore the previous program is overwritten. 

 


 

Q3. I can control mBot Mega with my mobile phone or Makeblock Bluetooth Controller through Bluetooth but can't upload a program with a Bluetooth dongle, why?

The Megapi main control board doesn't support firmware update, upload programs, or online debugging with a Bluetooth dongle.

 


 

Q4. Why do I need to install the electronic modules in the positions specified in the building instructions when I am to use mBlock 5 to program mBot Mega?

To use the default functions, the sensors need to be connected to the positions specified in the preset programs. Otherwise, the default functions can't be used properly.

 


 

Q5. MegaPi doesn't support multi-threading, why?

Due to resource limit, the single-chip Arduino doesn't support multi-threading currently.

 

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