Line Following Car

...It's a lot harder when the car is not programmable!

Class Name: EE/ME 7 (Introduction to Mechatronics)

Institution: Caltech (Undergrad)

Project Duration: November-December 2022

Project Description: Make a line-following car out of timers, op amps, and discrete electronic components

Other notes

As you can kind of see from the video the car did not really work perfectly. Here's an incomplete list of mishaps:

• I wasn't able to power it off batteries because the wires wouldn't really stick into the breadboard. I ended up using the bench (well, "floor") power supply. Also, the slight voltage differences between the batteries seemed to make my op amps unhappy

• I had a LOT of trouble incorperating op amps into my circuit:

  • Instead of having one non-inverting gain op amp I could have also used the provided circuit below from another lab (Courtesy Glen George, Caltech teaching professor). This would have made my control voltage more adjustable. 

           However, I didn't get that lab working very adjustably so to reduce complexity I decided to just go with one op-amp. Whenever I chained the op amps    together one of the three would act funny and mess things up for the other ones.

• Less is more: I troubledshooted my breadboard connections a LOT and had to completely rebuild them at one point. To reduce the number of jumper wires in the future I would probably choose a different design that didn't involve duplicating the same circuit on both halves of the car.

  • For example, using transistors to invert the PWM signal for one of the motors would have allowed me to give the two motors two different signals with just one LM556 dual timer.

• In the future I would write out my complete design before starting...I didn't really compute the mechanical requirements for the car to move until much later and was mainly putting together peices from my other labs on the fly.

  • I also kept switching out resistors on the fly so my final product doesn't fully match my design values