Why the Ultrasonic Obstacle Avoidance Mode doesn't work on mBot?

If you find your mBot cannot avoid obstacle when you set it in Ultrasonic Obstacle Avoidance mode, please follow below steps to do troubleshooting.

1. Make sure the ultrasonic module is connected to Port 3 (required by default program).
2. Double check the wiring of the ultrasonic module and make sure the connection is firm and well. Check whether the red indicator of the ultrasonic module is on. If not, the problem is caused by wiring.
3. Update the factory firmware for mBot, look here for detail instruction.
4. Press button B on the IR remote control to enter Ultrasonic Obstacle Avoidance Mode if you use the IR remote controller. When it set in Ultrasonic Obstacle Mode, onboard light should be green on.
5. Make sure the battery on mBot can provide enough power. According to our test and research, it is suggested to use rechargeable Li-ion battery or rechargeable nickel-metal hydride, nickel-cadmium which can be bought from amazon or local shop. Or Alkaline battery with good quality like Energizer, DURACELL.