1. 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%.

2. 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.

3. 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.

4. 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.
  

5. 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.

6. 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.

7. 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.

8. 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.