PE Lab Counters TestIrDutyDistanceDetector

SRLM

I'm working away at learning the Propeller, and came across this lab (page 31). I buit the IR circuit and the reciever circuit, and ran the provided code. Unfortunately, all the debug displays is a series of zeros, no matter what. I tried turning the LED around, no good. I tried replacing the LED. Did that with the five that I have. I tried replacing the reciever. No good. Likewise I tried it five times. I put a regular LED in place of the IR: it lights up just fine. Through all these changes, the debug terminal read 0. Any help?

Andy Lindsay (Parallax)

Hello SRLM,

You are probably working from v0.81.· I just posted v1.0 and recommend updating. It's available from the PE Kit Labs page.

http://forums.parallax.com/showthread.php?p=617192

Try that out, and please let me know if anything changes.

Also, if you are working from the Propeller Demo Baord instad of the PE Kit, make sure pin 3 on the IR detector is connected to + 5 V. Vdd on that board is 3.3 V doesn't have quite enough voltage to power the 5 V part.·

Andy

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Andy Lindsay

Education Department
Parallax, Inc.

Post Edited (Andy Lindsay (Parallax)) : 10/22/2008 11:44:17 PM GMT

SRLM

Ha. The circuit diagram was wrong (in v 0.8) . The IR detector signal is on the right hand pin, not the middle. That and a bad detector gave me problems. Thanks for the new, corected version. I guess I'll have to print the 50 pages over again... Unless you have a corrections sheet?

Anyway, question on range: I'm able to get about a 0 - 2 ft range. Normal? Not? at the outside of the range, I get 256. However, on the inside I get about 80. I can't help but think that there is an extra 8 in of range to be had. Would this be a correct assumption?

Andy Lindsay (Parallax)

SRLM,

Sorry about that. I thought I had updated the PDF and corrected that error a long time ago. Well, at least it's right in 1.0.

Yeah, your distances are about what I'm getting too, at least for obstacles. Your readings will approach zero if you face the IR LED at the IR detector's IR Phototransistor (the hemispherical bump on the case). You can definitely use that for the 80 to 0 range.

If you find any errors in 1.0, please either post them to this thread:

http://forums.parallax.com/showthread.php?p=648967

or email direct to editor@parallax.com.

Thanks, Andy

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Andy Lindsay

Education Department
Parallax, Inc.

Post Edited (Andy Lindsay (Parallax)) : 10/23/2008 12:54:37 AM GMT

Andy Lindsay (Parallax)

P.S. About reprint vs. list, I would recommend printing out a whole new one because every example that used HyperTerminal now uses Parallax Serial Terminal. Different code, illustrations, instructions, etc. There's a new section about half way through that would make all the pagination and figure references difficult to follow.

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Andy Lindsay

Education Department
Parallax, Inc.

SRLM

Okay. Although, in my version (v0.8) it seemed to work with the serial terminal. Maybe it was just luck...

Andy Lindsay (Parallax)

Hmm, yes, most of the old code examples should work with Parallax Serial Terminal; the formatting just won't look quite right. There'll be more carriage returns than if you use the code for the Parallax Serial Terminal.

That aside, I do not have a change tracking sheet because there are enough adjustments to make such a sheet quite·the rat's nest.

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Andy Lindsay

Education Department
Parallax, Inc.

SRLM

Okay. It's not my dime anyway, it the CS department's...