Minimalist 555 Line Follower

I successfully combined three of my recent passions into one tonight: cheap line follower robots, the magnificent 555 timer, and using copious amounts of alarmingly cheap Ebay China parts. I've been saying for ages that we're foolish for not using 4-cent 555 timers and multiple nickel photocells in every project. Well, that's nearly all I used here. I hacked one of the $5 Ebay line follower kits. Tossed the 393 comparator, two trimpots, two driver transistors, and four resistors. Now one 555 does it all: reads two photocell line sensors and drives two motors. Minimalism rules. Beau & PhiPi et al: any way to do it cheaper yet?


"When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

- Pablo Picasso

Comments

  • 23 Comments sorted by Date Added Votes
  • ercoerco Posts: 18,185
    BTW, I've wondered if a 555 could line follow ever since Parallax's amazing LFO course in 2012, so I can die happy now.

    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Too bad you didn't think of this a few years ago when they had the 555 contest. Hans Camenzind even was one of the judges, if I recall.
    San Mateo, CA
  • ercoerco Posts: 18,185
    Forgive me, Ken: 555 timer vs. Propeller multicore. :)





    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • ercoerco Posts: 18,185
    Jeff Haas wrote: »
    Hans Camenzind even was one of the judges, if I recall.

    Really? I would have liked to meet him!

    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Unfortunately the website for the contest is gone, but there are still articles about it up.

    Evil Mad Science helped judge the early rounds. Hans and Forrest Mims were final-round judges!
    http://www.evilmadscientist.com/2011/some-gems-from-the-555-contest/

    Then a year later Make had a retrospective after Hans passed away:
    http://makezine.com/2012/08/22/555-timer-contest-highlights/
    San Mateo, CA
  • @erco, The cheaper you get, the better they run.

    Nice and smooth.

    You should be working for NASA or the military, they could be looking to save a few bucks.
  • MikeDYur wrote: »
    @erco, The cheaper you get, the better they run.

    Nice and smooth.

    You should be working for NASA or the military, they could be looking to save a few bucks.

    Amazingly smooth for such a simple circuit. any idea what frequency the 555 is toggling at?
    In science there is no authority. There is only experiment.
    Life is unpredictable. Eat dessert first.
  • ercoerco Posts: 18,185
    Probably 200-400 Hz, depending on the lighting & photocells.
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Nice! I want to make one, can you post the code?

    Seriously though, I love the simplicity, but wasn't expecting it to be as smooth as it was.

    The S3 in your video sounds like a mad rooster.
  • ercoerco Posts: 18,185
    Ha, Yes, smooth. But no, can't turn too sharp, therefore the large radius. The photocells & LEDs are just hanging out in the breeze and the voltage differential isn't that great. Probably with some experimentation, isolation and aligning it could be improved.

    What's funny is that all these parts have been around since 1972. Why weren't there $5 robot line follower kits when I was growing up?
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • erco wrote: »
    What's funny is that all these parts have been around since 1972. Why weren't there $5 robot line follower kits when I was growing up?

    No eBay China, no $5 anything :)

  • ercoerco Posts: 18,185
    edited July 25 Vote Up0Vote Down
    Also uses two photocells. Cute.


    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • ercoerco Posts: 18,185
    Drats. For rock-bottom minimalism, I still can't beat this one-motor, no electronics line follower. :(



    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • The 555 timer is a fun IC to play with. I submitted an entry (555 Music Box Player) to the contest, which I found listed as one of the gems of the contest on the Evil Mad Science link/page below. Unfortunately my entry didn't make to the finals, but it was fun to participate anyway.
    Jeff Haas wrote: »
    Unfortunately the website for the contest is gone, but there are still articles about it up.

    Evil Mad Science helped judge the early rounds. Hans and Forrest Mims were final-round judges!
    http://www.evilmadscientist.com/2011/some-gems-from-the-555-contest/

    Then a year later Make had a retrospective after Hans passed away:
    http://makezine.com/2012/08/22/555-timer-contest-highlights/

    Along with 'Antimatter' and 'Dark Matter' we've recently discovered the existence of
    `Doesn't Matter`, which appears to have no effect on the universe whatsoever.
  • erco wrote: »
    Drats. For rock-bottom minimalism, I still can't beat this one-motor, no electronics line follower. :(

    No electronics?
  • Seairth wrote: »
    erco wrote: »
    Drats. For rock-bottom minimalism, I still can't beat this one-motor, no electronics line follower. :(

    No electronics?

    I had to look it up. Here's a hint, you have to use a smooth surface, like the included board, and something waxy like a crayon to draw the line.

  • ercoerco Posts: 18,185
    All mechanical.
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • I'm guessing two wheels, one on either side of the line? If one wheel gets on the line, it slips and causes the other wheel to pull back to center?
  • Somehow, I have the feeling that erco has a Hugo (movie) automaton at home...
    Prop Info and Apps: http://www.rayslogic.com/
  • ercoerco Posts: 18,185
    Rayman wrote: »
    Somehow, I have the feeling that erco has a Hugo (movie) automaton at home...

    I still haven't seen that movie, so I can neither confirm nor deny these allegations of impropriety. :)
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • ercoerco Posts: 18,185
    Seairth wrote: »
    I'm guessing two wheels, one on either side of the line? If one wheel gets on the line, it slips and causes the other wheel to pull back to center?

    Very good! Actually 3 wheels, all gear linked. One wide rear roller/wheel driving forward and two front rollers, rolling sideways in opposite directions straddling the line. The waxy crayon line is much stickier than the plastic mat, so that friction differential guides the car. Pretty slick mechanical stuff, circa 1977. The 555 timer was just 5 years old, and photocells (electric eyes!) were plentiful then. My cheap & cheesy method coulda been a contender!

    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
  • Turns on a crayon... I find it comforting to know that something worse than turns in reverse exists.
  • ercoerco Posts: 18,185
    You can see the 3 white wheels turning on the red chassis' underside at 4 seconds into that "Trail Tracker" video.
    "When you make a thing, a thing that is new, it is so complicated making it that it is bound to be ugly. But those that make it after you, they don’t have to worry about making it. And they can make it pretty, and so everybody can like it when others make it after you."

    - Pablo Picasso
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