This is the latest installment of the robot stuff for making patterns in the sand. So I managed to get the motors of the robot to run at different speeds in order to do smooth curves. It makes things a bit easier in a way. Describing curves is possible by  looking at it as line segments, but waaaaaay easier if you can incrementally adjust the motor speed settings. Here's the latest offering, a 760 second exposure - it's certainly a little more interesting:
And here's the perpetrator, or as I'm calling it "The Perpetrator":
The servo will be for lowering the stick/rake/device onto the sand. Yes, even I think that it might not work quite perfectly. Perhaps the trick will be to cause as much disruption to the surface of the sand with the least mechanical effort, so as not to strain motors and waste batteries. The real knack will be in doing a pattern which will be photographable (even I don't know if that a real word, my spell checker says it's not - blaaaaaaaaaah).
And here's the code for the PICAXE:
  let w1 = 3000 'forwards length
  let w2 = 4000 'pulse width
  let w3 = 120 'turn period (via for...next loop)
  high 0
check: let b1 = pins
  if b1 = 000010 then
  low 0
  pause 2000
  goto main
  end if
  goto check
main:  
  high 4 high 7  'forwards
  pause w1
  high 4   
  for w0 = 1 to w3  'turn
  pulsout 7,w2
  pause w0
  next w0
  low 4 low 7   'stop turning
  goto main
I'm so inefficient at programming, but it gets the job done, so hey.
D'you know, I almost forgot to say that the coolest and smallest thing on this robot is the RGB LED - how else would I get multicolour light lines for 50p?


 
 
This is so very cool! Excellent idea - your results are fantastic.
ReplyDeleteThanks, John, much appreciated.
ReplyDeleteOK, you have inspired me to try this as well. You can see my results here if you like.
ReplyDeleteOh, wow, those are awesome, just awesome. I bought a Full bridge IC the other day so that the bot would do this on sand, but I've yet to find two similar motors I can use.
ReplyDeleteFor motors you could try the surplus outlets. They usually have tons of gearhead motors:
ReplyDeletehttp://www.mpja.com/products.asp?dept=100
http://www.goldmine-elec-products.com/products.asp?dept=1300
http://www.allelectronics.com/make-a-store/category/400/Motors/1.html
And of course ebay is loaded with gearhead motors perfect for hobby robotics.
Would love to see pictures of the sand designs when you do them.