However, they are very expensive for just programming (maybe it is worth it for debugging purposes), this is why I have always used another Arduino board as ISP programmer ... ATMEGA8U2-MU in original ...

This step-by-step guide will show you how to build a professional-grade line follower robot using Arduino UNO, with complete code explanations ... The L293D has 16 pins, the pinout of L293D is shown ...