[Yaaarc] Fwd: RE: IR sensors

[George Albercook]

Here is a response from an e-mail I sent about this
same question.

George A.

--- Doug Leppard <Doug.Leppard at ccci.org> wrote:

> Subject: RE: IR sensors
> Date: Sat, 12 Aug 2006 11:20:16 -0400
> From: "Doug Leppard" <Doug.Leppard at ccci.org>
> To: "George Albercook" <albercook at yahoo.com>
> 
> Well it has been awhile since I worked on that.  I
> do a lot of FIRST
> robotics mentoring now.
> 
> The robot I had them on is still built, haven't
> operated it in years.
> The second robot moved well and sensed objects well,
> I learned a lot. 
> 
> Now for your questions.  Are you doing the fire
> fighting robot?
> 
> When IR sensors fire they tend to draw a lot of
> current for a short
> time.  My robot had lots of these sensors, two right
> wall, two let wall,
> 6 looking forward.
> 
> So what I did was put a 5V regulator on a pair of
> them with caps loaded
> on each set.  This kept the electrical noise down.
> 
> I don't think I had a problem with the D12s being
> blinded by the flame.
> They have filtering on them and that was not an
> issue.
> 
> BUT, with six D12s pointing forward, 4 of them same
> exact direction,
> they could give you false signals at a distance. 
> Problem is they can
> see each others signal and throw it off.  One IR
> what gave me a distance
> to the next wall I put in a black tube (toilet paper
> tube panted black),
> that way it kept the sensor from seeing other
> signals but did cut down
> distance it could read.
> 
> The reason I had so many sensors is that I was
> looking for objects it
> its path and move around them.  I can try to do a
> diagram if you want.
> 
> I hope this helps.
> 
> Doug Leppard
> 
> 
> -----Original Message-----
> From: George Albercook [mailto:albercook at yahoo.com] 
> Sent: Saturday, August 12, 2006 10:33 AM
> To: Doug Leppard
> Subject: IR sensors
> 
> Hello Doug,
> 
> I just read your "First Steps: Failures" article.
> Thanks for posting it. I'm thinking of doing
> something
> similar and had a question. I noticed that you use
> the
>  GP2D12 and the UVtron. That is exactly what I was
> thinking of doing.  
> 
> I read a couple posts about the GP2D12 having
> trouble
> with noise and with interference form flame.
> reportedly it both generates a lot of noise on the
> power line and sometimes sends erroneous signals. 
> It
> also reportedly "Sees" flame as a reflection.
> 
> Any thoughts? Have you had either of these problems?
> 
> Thanks for any time you can give.
> 
> Regards,
> George A.
> www.Flutterbot.com
>