2 Years ago I made a Arduino 4WD And it can be controlled through bluetooth. I also made an app in mit App inventor. I want to modify my app or the arduino code so when i press a button on the app it starts memorizing the instructions( Forward, backward, etc) until i click a stop button, Then when i press a third button the car retraces the path ( or the instructions). I hope you all understand me.. Thank you in advance..
Absolutely! Fairly simple to do so.
You will need some structure to store the list of commands and a process to interpret those commands (this will be very similar to the original process of following the rel-time commands)
There is a tricky part. Following a list of navigation commands by themselves rarely produces anything close to accurate navigation.
Turns by applying power to one side without applying power to the other are inaccurate. Variations in the surface, battery voltage and many other factors will affect this accuracy.
Going straight by applying the same power to both sides will drift. Even adding encoders to wheels does little to create usable navigation.
Adding things like a compass or other sensors lets your vehicle use positional awareness in navigation.
Edit: it will still be fun to do. Experiment with measuring the inaccuracy and seeing what you can do to reduce that.
Your car also memorizes the TIME it takes to perform one function before beginning the next. So yo will have to do this also.