STEM kit for everyone Tumbller is easy to assemble and suitable for kids to have some hands-on experiences and learn basic What is Tumbller? Tumbller is a newly designed Self-blancing robotic car kit which has multiple functions and offers you a great hands-on experience. It's also a DIY kit which helps kids with fostering creativity and inspires imagination. [Stand up by itself] Press the command key, it will tilt forward, and press the key again, it will stand up instantly and keep balance by itself. [Obstacle-Avoidance] Tumbller will avoid obstacles ahead of it automatically with the ultrasonic sensors on the platform by sending waves and calculating the distance. Keep your car away from collision and enjoy the fun. [Auto-follow] If there is an obstacle in front, Tumbller will move forward or backward with the obstacle. If there is an obstacle on the left or right side, Tumbller will turn left or right with obstacle. [Glowing] Press the command key, Tumbller will light up one light effect.Press it again, it will switch to another one. There are six light effects and you can switch according to your preferences. [The issues to be aware of when using Tumbller:] 1.The screw on the coupling might get loose after long-time working, please pay attention to lock it tight. 2.When DIY Control on the App, the message to make Tumbller turn right is "i" instead of "r". We wrote "r" in our paper manual. 3.When assembling the expansion board, if you find the infrared sensors on the sides are bent, please twist it a bit and make sure it stands up vertically on the board so it can work properly. 4.When you pick up the Tumbller vertically, the wheel will still rotate. After tilting the Tumbler 27, the rotation will stop. 5.Tumbller cant be used in places where the sunshine or light is too bright, because the strong brightness will affect the sensor. 6.The LED will flash red when the battery is running out of power. 7.The USB interface is only used for burning program. When burning program, please turn off the battery to prevent interference.