LK COKOINO Self Balancing Robot Kit with Two Wheels and R3 Board, Bluetooth Control, Easy to Assembly and Code, A Lot You Can Learn

I bought this for my Grand kids to play with. The first one I got had a bad Arduino card. I found that out after it was all put together. I send it back and received a second one. It had a bad servo. It would just make a loud buzzing noise and not move. I figured I could use it without it but was never able to get the car to work. The wheels would roll but the car would not balance. Also it uses a special battery type that's not readily available at most stores. I had to order them off of the internet. Getting the instructions for the device was very frustrating. There's a code to scan and it would not be read by my computer's camera. I email Customer support for them but never received a reply back. I ended up using my phone after installing a QR code reader and was able to get them that way. It just took some time to get them from the phone to my computer. All and all a very frustrating experience.

This robot is probably the best deal for this kind of project, Unless you want to buy and make parts individually.The one I received has everything functional. The only problem was: Amazon put in in tight box so plastic container was cracked.This set is actually pretty good platform to learn PID, Kalman filter, PWM, Hall encoder, Bluetooth and serial communication in Arduino Uno context. So if you want to get physical understanding of these concepts - this set will do it. All code and exercises are supplied in documentation. Comments are mostly in Chinese, but there is some english there also :)For next version it would be nice to add battery voltage resistor divider circuit wired to analog input to stop motors when batteries are low.