Let's Make Robots!

AVR Line Follower

Simple Line follower, with additional ability to stop when objects are detected in front of it and turn around when the end of a line is detected.

I built this robot for a University course on C Programming, and later (after my assessment, although before the end of the course) added the tank tracks to replace the original Tamiya truck tyres. As such, all parts were supplied by the university, and as my course fees were paid by my school there was no charge to me. All extra parts were found lying round my garage, including the tracks and extra mounting hardware.

The course required, for top marks, that the robot must be able to:


  • follow a black line
  • stop, for ten seconds or until a switch was pushed, whenever a grey line was crossed
  • be able to cross a white or black line without deviating
  • be able to stop when an object is detected in front of it, and continue when it was removed
  • stop when the end of a line was detected, and after five seconds turn around and continue 


Before the modifications, it met all of these requirements, although due to it's decreased speed with the tracks it now has trouble with crossing some black lines as it no longer can just shoot over them. It still meets all the other requirements, even though, with an increased wheelbase, it's steering has been dramatically reduced.

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Nice work!

Now that it has been set free from the constraints of uni assesment criteria do you have any grand plans for it or other modifications you'd like to make?

Not really. I may use it in the future as a test bed if I decide to start using Amtel chips for most of my projects, however my long term plan is to move from the Picaxe chips I use now in projects like my robotic arm, to their father chips, the Microchip PIC's, over the course of 2010. My plan is to get a decent understanding of assembler code before I go to university, and besides, PIC's aren't static sensitive as far as I know. C isn't a hard language to learn, and If I find assembler too hard, I may fall back to it as I really want to escape the programming limitations of basic.

Nice Robot ;)

Have built the sensors yourself ,or did you buy them ?

The sensors were supplied by the university. Although the project uses four (three underneath, and one at the front), I used nine over the 4 day course, of which one was faulty and the rest had leads that were too short after the tracks increased the ground clearance and the distance between the pcb and the front of the robot. The last four I've kept for future projects.