+ Reply to Thread
Page 1 of 2 12 LastLast
Results 1 to 20 of 23

Thread: Smart Bumper for Robot

  1. #1

    Default Smart Bumper for Robot

    Details to follow. Good stuff, stay tuned!

  2. #2

    Default Re: Smart Bumper for Robot

    You are both cruel and unusual... ;-)
    Whit+

    "We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths." - Walt Disney

  3. #3

    Default Re: Smart Bumper for Robot

    It will be worth the wait, I promise. So much info from just ONE i/o pin!

    Just acquiring the final hardware now, then fabrication, test, & video!

  4. #4

    Default Re: Smart Bumper for Robot

    A teaser message to start the thread. Hmm, I feel manipulated and yet interested.

  5. #5

    Default Re: Smart Bumper for Robot

    Quote Originally Posted by erco View Post
    It will be worth the wait, I promise.
    Well...Okay.
    Whit+

    "We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths." - Walt Disney

  6. #6

    Default Re: Smart Bumper for Robot

    I seem to recall Mike Green telling someone that teasers where against forum rules.

    I thought Matt Gilliland was the only one allowed to post teaser threads.

  7. #7

    Default Re: Smart Bumper for Robot

    Uh-oh. My bad, don't want no forum trouble, especially from my hero Mike Green... I better come clean: long wraparound perimeter bumper is a potentiometer switch. Any contact is readable on one pin, ADC or RCtime tells you where you're hitting. Hi resolution yields accurate object location and is much simpler than having many many many individual bump switches.

    PHEW. Am I off the hook temporarily?

  8. #8

    Default Re: Smart Bumper for Robot

    Quote Originally Posted by erco View Post
    PHEW. Am I off the hook temporarily?
    I'd say you still have a lot of community service left on your sentence.

    Are you talking about one of these? If so that's a great idea. (I have one, I might use it this way.)

    If not it's probably still a great idea. I just don't know what you're talking about.

    Duane

  9. #9

    Default Re: Smart Bumper for Robot

    Good call, Duane! Very similar; I got the 1000 mm Softpot from Digikey: http://search.digikey.com/scripts/Dk...me=905-1040-ND

    And I'm building a 13" diameter chassis as we speak. Plastic? Nah. Plyood? Yeah!

  10. #10

    Default Re: Smart Bumper for Robot

    Wow, I didn't know they made plywood Softpots?!

    Edit: Can we pretend I didn't make such a dumb joke? Apparently by sense of humor has already gone to sleep. It's time for the rest of me to follow. I wish it weren't against my religion to delete posts or I'd delete this one.

  11. #11

    Default Re: Smart Bumper for Robot

    T'sa custom job...

  12. #12

    Default Re: Smart Bumper for Robot

    These are good, but there are a couple of issues to consider:

    1. The SoftPots aren't sealed, so be careful using them outdoors. They sell a HotPot line, which are sealed, but these require more pressure to actuate.

    2. Very hard impacts will permanently damage the membrane. You'd be wise to put the strip within a recess so that it won't take the full force of hit.

    3. It's not possible to read multiple contact points. It will register the nearest point only. (One way around this is to use a second strip, mounted in reverse direction. Then you can tell if there's at least two separate contact points. This is a pretty expensive route, though.)

    I think they're fine as a failsafe for when proximity detection missed an object. Given a one meter strip, and assuming one loop around the robot's base, I'm guessing a one foot diameter bot. That's no bantam weight. With that kind of mass, given any speed at impact your SoftPot may not last long. So be gentle to it!

    You might also consider putting some foam on the outside as a cushion. I don't know how that will affect its sensitivity, but it would probably help it to last longer in the Erco household.

    -- Gordon

  13. #13

    Default Re: Smart Bumper for Robot

    Maybe running a ring of vinyl tubing around the outside of the SoftPot? It might be possible to get some that's rigid enough to give a good contact and soft enough to protect the SoftPot.

  14. #14

    Default Re: Smart Bumper for Robot

    You boys are right on frequency. The Softpots are fragile, if they get kinked or hit too hard I suspect that's the end of them. Digikey shipped it to me STRAIGHT in a huge box, 4 feet long by ~10" triangular cross section. Seems like overkill. How about a mailing tube?

    I'm not a huge fan of circular robots, but yes, this one will be 13" diameter to keep the bend as gentle as possible. And the plan is to have vinyl or surgical tubing all the way around for protection.

    You guys are sharp!

  15. #15

    Default Re: Smart Bumper for Robot

    In my case not sharp, just wise (been there, done that wise).

    Something that would expand the surface area of a bump vertically but not so much horizontally would probably benefit the SoftPot. The combination of the recess and the tube could help prevent the strip from the full force of the impact. As the tube compresses it spreads out to the recess, filling it, and preventing the object from going any deeper -- the object hits the ridges of the recess as a hard stop.

    Maybe you could find an inner tube that's the right size. Steal the one from your kid's first bicycle, maybe. Fill it up to the pressure that still registers the bumps in more or less the right spots.

    -- Gordon

  16. #16

    Default Re: Smart Bumper for Robot

    I like that inner tube idea or even using a thick rubber band or slice of a bike tire. Good thought.

  17. #17

    Default Re: Smart Bumper for Robot

    Softpot installed on my new wooden chassis and the first test looks good: http://www.youtube.com/watch?v=aVF6ETof3tE

    I think large surgical rubber tubing will work well as a protective bumper.
    Attached Thumbnails Attached Thumbnails Click image for larger version

Name:	small2.jpg‎
Views:	107
Size:	71.1 KB
ID:	82175   Click image for larger version

Name:	small1.jpg‎
Views:	92
Size:	57.3 KB
ID:	82176   Click image for larger version

Name:	small3.jpg‎
Views:	98
Size:	55.4 KB
ID:	82178  

  18. #18

    Default Re: Smart Bumper for Robot

    Cool idea and "oohs" and "ahs" for a round wood robot.

    How does a liner pot react if there are two points of contact? Does it act like resistors in parallel?

  19. #19

    Default Re: Smart Bumper for Robot

    Great idea erco! Hope you find a good way to protect it from damage and still be effective.

  20. #20

    Default Re: Smart Bumper for Robot

    @Martin_H: two points of contact= the end of humanity as we know it

    Or, just the same as the lowest resistance reading.

    Whichever comes first.

    @Ron: It's guaranteed to work at least until the first good impact.

+ Reply to Thread

Similar Threads

  1. Bumper Bump
    By Sing America in forum BASIC Stamp
    Replies: 1
    Last Post: 11-10-2009, 09:23 AM
  2. autonomous bumper bot with bs2
    By epicjr77 in forum BASIC Stamp
    Replies: 2
    Last Post: 04-17-2008, 08:49 AM
  3. Need bumper and ir help ?
    By alleykat in forum BASIC Stamp
    Replies: 1
    Last Post: 02-02-2007, 02:14 AM
  4. bumper skirt
    By ltmhall in forum BASIC Stamp
    Replies: 2
    Last Post: 01-06-2007, 06:55 AM
  5. Bumper Boe -Bots
    By musictech in forum BASIC Stamp
    Replies: 2
    Last Post: 04-20-2005, 01:08 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts