Subject:
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Re: IR Sensitivity - Was: 1.5/2.0 infrared problem
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Newsgroups:
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lugnet.robotics.rcx
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Date:
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Thu, 23 Oct 2003 03:33:18 GMT
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Viewed:
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4957 times
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chip 1138 / chip 1176
Strange... 38 + 38 = 76
What does that mean?
Rob
"Mark Riley" <markril@hotmail.com> wrote in message
news:Hn6xKJ.1o68@lugnet.com...
> In lugnet.robotics.rcx, Chris Masclet wrote:
> > In lugnet.robotics.rcx, Chris Masclet wrote:
> > > Hi I've got two RCX: a 1.5 and 2.0 version.
> > > I' ve got a problem with IR emiter/reicever.
> > > The 1.5 version seems to be more sensitive to reflected infrared and • its
> > > good to use !
> > > But the 2.0 RCX is less sensitive and for example doesn't receive • reflected
> > > message from my remote control or 1.5 RCX.It has to be exactly in the • axle
> > > to receive IR.
> > > Does anybody know about it?
> > >
> > > CHRISMAKER
> >
> > we ' ve told about this thing with Philo few days ago cause he had the • same
> > problem.
> >
> > So I' ve made several tests with 4 RCX: 2 RCXv1.0 and 2 RCXv2.0 .
> >
> > It seems RCX emitter is the same in 1.0 and 2.0 versions.
> > But 2.0 receiver is less sensitive than 1.0's one..........
> >
> > This is a weird thing!!!
>
> I think there might be an explanation for this and I've been meaning to • post on
> this topic, but never seem to have gotten around to it! :-)
>
> I've opened up my RCX 1.0 and the IR receiver has the markings "TSOP 1138" • on
> it. After looking this part number up, it appears it is an IR receiver
> sensitive to a 38KHz IR carrier. This is the "normal" carrier for RCX • messages.
>
> However, my RCX 2.0 has an IR receiver with "TSOP 1176" markings. I • couldn't
> find any info on this part, but knowing that a TSOP-1140 is an IR receiver • for a
> 40KHz carrier leads me to extrapolate that the IR receiver in my RCX 2.0 • is
> sensitive to a 76KHz carrier (double the 38KHz carrier).
>
> Now, as has been mentioned here before, the Spybot and Manas remotes send • IR
> messages using a 76KHz IR carrier. My RCX 2.0 can receive these messages • just
> fine, while my RCX 1.0 struggles to receive these messages even with the • remote
> a few inches from the RCX.
>
> While the TSOP-1176 is also apparently sensitive to a 38KHz carrier • (otherwise
> it couldn't receive normal RCX messages), it may be with less sensitivity • than
> the native TSOP-1138. This could be the reason for the observed • differences in
> IR reception between the different RCX versions.
>
> Mark
>
> BTW, the TSOP-1176 part is also used as the receiver in Spybots and Manas • motor
> units.
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Message is in Reply To:
 | | IR Sensitivity - Was: 1.5/2.0 infrared problem
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| (...) I think there might be an explanation for this and I've been meaning to post on this topic, but never seem to have gotten around to it! :-) I've opened up my RCX 1.0 and the IR receiver has the markings "TSOP 1138" on it. After looking this (...) (21 years ago, 23-Oct-03, to lugnet.robotics.rcx)
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