1. Why doesn't mBot Ranger work in Line Following mode?

We suggest you put the line following map in a place where the light is weak when you test mBot Ranger. The line follower sensor doesn't work so well in strong light.

When you use the line follower module, if mBot Ranger can't complete a line following task with a line following program for it, you can perform the following checks for the line follower module in order.

(1) Check the quality of the module

Connect the line follower module to a port on the main control board, power on mBot Ranger, put mBot Ranger in a place close to a white paper or a white desktop, and see if the two blue LEDs on the line follower module are on (normally, the two LEDs are on when the distance between mBot Ranger and the desktop or the white paper is about 1cm, and the two LEDs are off when mBot Ranger is far away from the desktop, as shown in the following picture).

If none of the above situations occurs, you can replace the RJ25 cable for the line follower module, or connect the line follower module to another port on the main control board, to rule out the possibility of a power supply failure on the main control board.

(2) Check the connection

In the default Line Following mode of mBot Ranger, line following fails if the line follower module is not connected to port 9 on the main control board.

-If line following still fails in default Line Following mode, you can try to update the firmware.

(1) Check if power is normally supplied

Connect the ultrasonic module to the main control board, power on the main control board, and see if the red PWR light at the back of the module is on normally (as shown in the following picture).

If the indicator is off, you can replace the RJ25 cable, connect it, and see if the indicator is on. If the indicator is still off after replacing the cable, it indicates that something is wrong with the ultrasonic module.

(2) Check if the connection is correct

In default, Avoid Obstacle mode of mBot Ranger, the ultrasonic module should be connected to port 10 on the main control board (if you compile the program, check if the port connected to the ultrasonic module is the same as that in the program).

(3) Read values on the PC client of mBlock 5

Firstly, update the firmware of the mBot Ranger. Secondly, connect mBot Ranger to mBlock 5, and select the Live mode.

Lastly, select the check box on the left of the ultrasonic sensor port 10 distance block (the port connected to the ultrasonic module should be the same as that on the stage), and see if the value at the top left of the stage changes.

3. When I connect mBot Ranger to [Makeblock] App, the system displays [Firmware unrecognized]. Why?

When you connect mBot Ranger to [Makeblock] App, if the connection fails with any of the following prompts, you can do troubleshooting by following the instructions below.

(1) Low battery

We recommend that you use 6 new dry batteries with good performance or the rechargeable lithium-ion battery pack provided by Makeblock (as shown in the following picture), for they have a strong discharge capacity. Dry rechargeable batteries are not recommended.

(2) Low version of [Makeblock] App or firmware of mBot Ranger

• To solve the problem of the low version of [Makeblock] App, you can download the latest version from the software application store (App Store for iOS or Tencent MyApp for Android is recommended).
• To solve the problem of the low mBot Ranger firmware version, you can read How to install firmware in the FAQs and upgrade firmware to the latest version.

4. Why does mBot Ranger go and stop from time to time while beeping?

After you connect mBot Ranger to [Makeblock] App and control it on the Drive interface, mBot Ranger goes and stops from time to time while beeping. In this case, you can troubleshoot in the following order.

(1) Low battery

We recommend that you use 6 new dry batteries with good performance or the rechargeable lithium-ion battery pack provided by Makeblock, for they have a strong discharge capacity. Dry rechargeable batteries are not recommended.

(2) Tight track

You can take the track off, control mBot Ranger with [Makeblock] App, and see if the motor can rotate normally. If the motor can rotate normally now, but can't rotate after the track is installed, it may be tight track caused by positioning error of metal beams upon assembly. You can check it by reading the instructions, or reassemble mBot Ranger.

5. Why can't mBot Ranger keep balance in Nervous Bird mode?

mBot Ranger can't keep balance after you assemble it into a Nervous Bird (as shown in the following picture), connect it to [Makeblock] App, and select the Nervous Bird mode.

You can see if it is due to any of the following reasons.

(1) Inverse connection of motor cables

Swap the connecting positions of the two motors on the main control board. That is to say, connect the motor connected to port M1 on the main control board to port M2, and connect the motor connected to port M2 to port M1.

(2) Low battery

• If power is supplied by using a battery compartment, you can insert 6 new dry batteries with good performance. Don't mix old and new batteries.
• If you use the 18650 lithium-ion battery pack provided by Makeblock, we recommend you try again after charging the batteries for a while. You can adjust the assembly position of the lithium-ion battery pack at the same time.

(3) Assembly problems

Assembly problems (such as positioning errors of metal beams and loose screws) can lead to instability of the center of gravity, and even affect the self-balance mode. When the motor can't regulate balance normally, you can check carefully by reading the assembly instructions. The following picture shows a positioning requirement for assembly (hole 1 and hole 3 should be locked with screws while hole 2 should be kept unlocked).

(4) Motor problems

If you have any other blue 180 motor, you can replace the motor, and see if the problem still exists then.

6. When I use [Makeblock] App to control mBot Ranger, the track comes off or is too tight. Why?

It is usually because of positioning errors of metal beams or wrong use of wheels (there are 8 black wheels of two sizes in the kit, and 6 small wheels of the same size are used in Land Raider mode) upon assembly.

In this case, you can read the paper instructions packed or the Build in [Makeblock] App before carefully checking the assembly. You can also dismantle the metal structural parts and then reassemble them when necessary.

7. After I power on mBot Ranger, it moves around. Why?

It is usually due to the change of building form. For example, you build mBot Ranger as Land Raider now, but you built it in another form (such as Nervous Bird) before. The hardware (building form) changes, but the software (firmware of the main control board) doesn't change due to the memory of the main control board, so mBot Ranger hasn't been changed from another form to Land Raider yet.

You can change the firmware of the main control board, from another form to the current form (supposing mBot Ranger is built as Land Raider), by selecting the form of mBot Ranger (select it based on the actual form). You only need to complete the following two steps for the change.

(1) Power on mBot Ranger and open [Makeblock] App, and then connect them via Bluetooth.

(2) After you connect mBot Ranger with [Makeblock] App, click Play, and then select Drive.