Thank you STEVE and VORPAL...

[REal ist]

Hello everyone. First of all, I thank my friend Steve forever. He is a very smart, entrepreneurial and successful friend. I hope he gets more of his work. Steve, your project is very good and I have successfully completed it. I can't wait to show it to my little boy. He will love it too. I want to share the problems I have encountered. First of all, bad engine problem. Especially stay away from sg90. There may also be bad ones in the MG 90s. In this case, the broken motor will draw excessive current and its batteries will fail. This is one of the reasons your robot collapses on the ground. Same with the UBEC problem. Definitely buy the ubec circuit that Steve recommends. Another problem is AT commands. Although I did the AT commands successfully, I tried a lot because I mixed the RX and TX pins each time. After all, the project works great. Pay attention to these. If there are any questions, I can help. Thanks again Steve bro. :) :) :)

[REal ist]

And 
Greetings to everyone from Turkey....

8 Şubat 2021 Pazartesi tarihinde saat 18:39:58 UTC+3 itibarıyla REal ist şunları yazdı:

[vorpalrobotics]

Thanks so much for the kind words, and glad you got the project working! 

Yes you can't use sg90 for this project and other substitutions may or may not work. If you self-source parts, that's fine but be prepared to work through issues that crop up.