Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: Stephanie on July 30, 2009, 10:21:19 PM

Title: Sharp IR interference
Post by: Stephanie on July 30, 2009, 10:21:19 PM

Hello guys!

I was looking at SoR member tutorials and saw this:

(http://www.huv.com/miniSumo/seeker2/Close-IR.jpg)

I plan to make an identical setup (side-by-side, tilted horizontally), but I don't know if they'll interfere with each other (I've never used Sharp IR).

Has anyone here ever tried to put IR Rangefinders that way? I don't have the sensors here to test...

Title: Re: Sharp IR interference
Post by: Stephanie on July 30, 2009, 10:24:41 PM

Double post, sorry

Title: Re: Sharp IR interference
Post by: SmAsH on July 31, 2009, 01:44:55 AM

well, as long as the beams don't interfere with one another there shouldn't be a problem...
one other thing you could do is have them going off one by one if interference is a problem.

Title: Re: Sharp IR interference
Post by: wil.hamilton on July 31, 2009, 06:03:20 AM

unless the beams were completely out of phase with one another (in which case they would disappear) there should be no problem.  The way the sharp ir works is by reflected IR light, so, more ir light to reflect you'd think would be better (although, i could be wrong here...., this is just my intuition talking here)

Title: Re: Sharp IR interference
Post by: Soeren on July 31, 2009, 06:48:33 AM

Hi,

Quote from: SmAsH on July 31, 2009, 01:44:55 AM

well, as long as the beams don't interfere with one another [...]

Hey, this isn't The Ghostbusters ;D

If one unit can "see" the other units beam, the range _will_ be upset in some degree.
If that's the case, break them apart and synchronize them.

Title: Re: Sharp IR interference
Post by: emoseman on August 04, 2009, 10:44:38 AM

Out of curiosity why would the the IR sensors be placed so close together?  Wouldn't one suffice?  Or are you trying to get a wider range of depth detection with an IR sensor?

Would a single IR sensor mounted on a servo that swings the sensor back and forth work to the same effect?

Just thoughts...

--
Evan

Title: Re: Sharp IR interference
Post by: wil.hamilton on August 04, 2009, 10:52:18 AM

@ evan:

they could have different ranges
one could be for farther away (30cm to 1m)
the other could be for up close (4cm to 30cm)
that way you have a better fidelity reading of your environment

Title: Re: Sharp IR interference
Post by: emoseman on August 04, 2009, 10:54:44 AM

Ah that makes sense, I hadn't thought of that...

--
Evan

Title: Re: Sharp IR interference
Post by: Stephanie on August 04, 2009, 06:19:01 PM

Actually, the reason is this: in the competition I'm participating, there is a limitation in the number of motors. A servo is, in theory, a DC motor. And, since I need to follow my opponent (it's sumo), I need at least two to decide where to turn (if the opponent escapes from one of the sensors). The max number of sensors I can use is high, so I'm using two there.

Title: Re: Sharp IR interference
Post by: emoseman on August 05, 2009, 01:36:26 PM

Ah gotcha, that makes sense too. :)

Good luck in the competition!

--
Evan