mBot Ranger freezes with android app, and then resets


I have a brand new mBot Ranger kit. I have followed the instructions for building the Land Raider. I then downloaded the android mBot app, and successfully operated the Land Raider using the manual mode and the virtual joy stick. However after successful operation for about 15 minutes, the next time we connected the robot with the app the manual mode begain to perform poorly. We can connect the app in bluetooth mode, and operate the robot for about 5-10 seconds before the controls freeze. at this point, after about 10-20 seconds the robot resets on it’s own. if I reconnect the bluetooth, it will work for approxoimately 5 seconds again, and the process repeats.

The app is installed on a nexus 7 tablet running 6.0

BTW: if i turn on object avoidance mode, this seems to work correctly.

Any ideas on what’s going on?
thank you


Hi wdmcgrory,

This should be the issue on battery. It is easily for ranger to function abnormal if the battery cannot provide enough power.
It is suggested to use rechargeable Li-ion battery or rechargeable nickel-metal hydride or nickel-cadmium which can be bought from amazon or local shop.
Or you can use Alkaline battery with good quality like Energizer, DURACELL while this kind of battery may not supply enough power for long time.
Since the Ranger is a robot which need high power during its operation which it easily consume the power in the battery, please change the battery have a check.

Besides, do you use the makeblock APP HD since the mBot APP is for mBot only not for Ranger?


Thank you for the information,
I originally used fresh energizer alkaline batteries, and will try replacing with fresh again, and see if that solves my problem.

Looking at the specs for Li-ion batteries I see that they are rated at 3.7ish volts. I looked for specs on the arduino mega 2560 and see max input voltage of 20. is the 22ish volts safe for this board?

And yes, I am using the HD app.


Hi wdmcgrory,

It is better to use the battery which provides input voltage in the normal range.
Here is a battery which I borrowed from my colleague and Ranger works very well with it. just to you for reference


So, you have ranger kit and building land raider for that reason download mBot Application. But within some seconds that’s not working as well. In that point I can suggest you a site where you can download application without any bug. Most of the time I downloaded apk from here.


You can also use APK Pure or SourceForge. (Assuming that anyone looking at this uses Android).