Line Following Robot

Back in 2011 I was at the library in Mesa Arizona with my wife. I'll be honest this was the first time I'd stepped foot in a library since I was a kid. I feel really bad about that now, because libraries are awesome and should be used by everyone! At any rate, I was a captive audience and I thought that I should try to make the most out of my visit, so I started looking for electronics books. I found several books, but one in particular that I found interesting was David Cook's Robot building for beginners. In his book David walks you through the steps of building a line following robot while teaching you the basics of electronics in a simple to understand way. I checked out this book and left the library excited to build a line following robot!


  • (1) Breadboard and lots of jumper wires
  • (1) Red 5mm LED and (1) 1kΩ resistor (for optional use as a power indicator)
  • (2) CdS photoresistors (aka photocells or light dependent resistors)
  • (1) 100Ω resistor 
  • (1) 20kΩ potentiometer
  • (1) LM393 dual comparator
  • (2) PNP 2N3906 transistors
  • (4) 1kΩ resistor
  • (2) Green 5mm LED
  • (2) 1N4001 flyback diodes
  • (2) geared DC motors with wheels
  • (1) sandwich container

This project post is still being written! Thanks for your patience!

Step 1: The eyes

Building a voltage divider circuit

Step2: The brains

LM393 dual comparator

Step3: The muscles and 'legs'

Step4: The skeleton

Step 5: Building a track

Zach HippsComment