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Electronics => Electronics => Topic started by: aruna1 on December 05, 2009, 12:01:42 PM

Title: wide angle obstecle detector
Post by: aruna1 on December 05, 2009, 12:01:42 PM

hello guys
I know that sonar sensor has wide detecton angle so basically it can cover front side of small robot entrely without rotating the sensor,due to sonar signals cone shape.
Iwas wondering if this is possible with IR obstecle detectors (TSOP based simple circuit) ,how to cover front side of small robot with one IR detector.
any ideas?
thanks

Title: Re: wide angle obstecle detector
Post by: definitionofis on December 10, 2009, 08:27:39 AM

I think if you placed a very small right-angle prism in front of the IR
detector, you could get a dual input to the detector. One input would be
forward through the prism and the other would be 90 degrees coming in from
the internal reflection of the hypotenuse of the prism.
I've never done it. It was just a thought.

Title: Re: wide angle obstecle detector
Post by: Soeren on December 10, 2009, 09:24:57 AM

Hi,

Quote from: aruna1 on December 05, 2009, 12:01:42 PM

[...] due to sonar signals cone shape.
Iwas wondering if this is possible with IR obstecle detectors (TSOP based simple circuit) ,how to cover front side of small robot with one IR detector.

It sort of depends on both the width and length of you 'bot and how far in front of it you want it to be how wide.

You wouldn't need to use the full range of the TSOPxxxx (from 10m to 30m = 30' to 90' with direct light), so you could take advantage of the wider "beam"  at a lower range (120° with some of them).

You can test this with your TV or HiFi - when you're far away, you have to be at a direct line of sight in front of it, but if you're close to it, you can usually zap from ackward angles.

Many remotes will work if you stand say 2m in front of it and zap towards your own body, simply by you reflecting enough IR to operate the receiver.

Further, you will get some spread from the diffusion of the IR on the object.

Title: Re: wide angle obstecle detector
Post by: definitionofis on December 10, 2009, 03:09:37 PM

That reminds me of this.

When Your Sensor Needs Glasses

You could very likely use a cheap, very small glass, biconcave lens with a short focal point
to broaden the input angle enormously.
I've haven't tried that either.

I did do the "IR remote control bouncing off a projector screen" with the target
equipment at the back of the room behind me.  It works.

Title: Re: wide angle obstecle detector
Post by: aruna1 on December 13, 2009, 08:00:15 PM

thanks  :)