<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Robert and all, <div class=""><br class=""></div><div class="">So, here is what I am thinking, please let me know if there is a better way.</div><div class=""><br class=""></div><div class="">1) Transmitter - use a LMC555 timer to deliver 10 , 1uSec pulses a second in Astable mode. The <a href="http://www.ti.com/lit/ds/symlink/lmc555.pdf" class="">data sheet</a> for the LMC555 timer says it can handle . This circuit will be turned on and off by the Arduino but that is all no PWM or triggering required. It will drive a 100mA 850nm <a href="http://www.marktechopto.com/pdf/products/datasheet/MTPS8085P_2015-05-07.pdf" class="">emitter</a> with a very focused beam.</div><div class=""><br class=""></div><div class="">2) Receiver - I will use a <a href="http://www.vishay.com/docs/81527/bpw77n.pdf" class="">matched 850nm phototransistor</a> wired as a common emitter amplifier. That way, the received pulse will cause the interrupt pin to go LOW and wake the Arduino. </div><div class=""><br class=""></div><div class="">3) Software, I will create a simple interrupt service routine that will register a pulse and determine how many if any pulses have been missed. I can use a running average smoothing function to get rid of noise so I don’t count a falling leaf.</div><div class=""><br class=""></div><div class=""><img height="212" width="429" apple-width="yes" apple-height="yes" apple-inline="yes" id="50FF1771-523B-4C9B-9AF3-3E77E54EC996" src="cid:BD4133C7-AD98-4547-99DD-2A04C35359DE@hil-sanmvhf.snd.wayport.net" class=""><img height="215" width="169" apple-width="yes" apple-height="yes" apple-inline="yes" id="C773BF30-33F3-4F54-8A78-35C4E5433181" src="cid:FE8425D0-7A93-445B-B4D1-7AC88EB26B2D@hil-sanmvhf.snd.wayport.net" class=""></div><div class=""><br class=""></div><div class="">I hope I am not missing something. Is there a better way to do this? Will I run into issues with changing ambient light or rain / snow causing problems? Will see but any heads up are appreciated.</div><div class=""><br class=""></div><div class="">Thanks,</div><div class=""><br class=""></div><div class="">Chip</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Aug 24, 2016, at 10:00 AM, <a href="mailto:triembed-request@triembed.org" class="">triembed-request@triembed.org</a> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">Send TriEmbed mailing list submissions to<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><a href="mailto:triembed@triembed.org" class="">triembed@triembed.org</a><br class=""><br class="">To subscribe or unsubscribe via the World Wide Web, visit<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>http://mail.triembed.org/mailman/listinfo/triembed_triembed.org<br class="">or, via email, send a message with subject or body 'help' to<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>triembed-request@triembed.org<br class=""><br class="">You can reach the person managing the list at<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>triembed-owner@triembed.org<br class=""><br class="">When replying, please edit your Subject line so it is more specific<br class="">than "Re: Contents of TriEmbed digest..."<br class=""><br class=""><br class="">Today's Topics:<br class=""><br class=""> 1. Re: TriEmbed Digest, Vol 39, Issue 16 (Robert Gasiorowski)<br class=""><br class=""><br class="">----------------------------------------------------------------------<br class=""><br class="">Message: 1<br class="">Date: Tue, 23 Aug 2016 16:16:57 -0400<br class="">From: Robert Gasiorowski <rgresume@gmail.com><br class="">To: Chip McClelland <chip@mcclellands.org><br class="">Cc: "triembed@triembed.org" <triembed@triembed.org><br class="">Subject: Re: [TriEmbed] TriEmbed Digest, Vol 39, Issue 16<br class="">Message-ID:<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><CAEU50hUQ+S3f4_KTHTAXRCEmMx_tGiuGeb1k61Wq1atiCf12dw@mail.gmail.com><br class="">Content-Type: text/plain; charset="utf-8"<br class=""><br class="">If you decide to use 38kHz carrier, you will either use a lot of energy or<br class="">limit your distance.<br class="">Here's my suggestion:<br class="">1. set IR LED's current to 100mA or higher (up to 1A,)<br class="">2. send 1us-5us pulses, 10 to 50 per second,<br class="">3. use pin interrupt and timer to detect and count missing pulses<br class="">4. use lens (LED) and IR filter (detector)<br class=""><br class="">Alternatively, you could use short bursts of 38kHz carrier (also at higher<br class="">current, but probably not as high as above.) This way, you could use one of<br class="">Vishay's detectors, which usually come with IR filters.<br class=""><br class="">On Tue, Aug 23, 2016 at 1:23 PM, Chip McClelland via TriEmbed <<br class="">triembed@triembed.org> wrote:<br class=""><br class=""><blockquote type="cite" class="">Alex, yes, bought and tested that one. But humans are not reflective sir<br class="">only about 12'. Cars to 30' easy so will eventually use it to replace the<br class="">pneumatic tubes across the road.<br class=""><br class="">Bought a matched pair of IR emitter and phototransistor yesterday. Will<br class="">see if I can build my own circuit as this seems to be a new and novel<br class="">application (!?).<br class=""><br class="">Thanks, chip<br class=""><br class="">On Tuesday, August 23, 2016, <triembed-request@triembed.org> wrote:<br class=""><br class=""><blockquote type="cite" class="">Send TriEmbed mailing list submissions to<br class=""> triembed@triembed.org<br class=""><br class="">To subscribe or unsubscribe via the World Wide Web, visit<br class=""> http://mail.triembed.org/mailman/listinfo/triembed_triembed.org<br class="">or, via email, send a message with subject or body 'help' to<br class=""> triembed-request@triembed.org<br class=""><br class="">You can reach the person managing the list at<br class=""> triembed-owner@triembed.org<br class=""><br class="">When replying, please edit your Subject line so it is more specific<br class="">than "Re: Contents of TriEmbed digest..."<br class=""><br class=""><br class="">Today's Topics:<br class=""><br class=""> 1. Re: TriEmbed Digest, Vol 39, Issue 15 (Alex Davis)<br class=""><br class=""><br class="">----------------------------------------------------------------------<br class=""><br class="">Message: 1<br class="">Date: Mon, 22 Aug 2016 13:28:21 -0400<br class="">From: Alex Davis <alexd@matrixwide.com><br class="">To: triembed@triembed.org<br class="">Subject: Re: [TriEmbed] TriEmbed Digest, Vol 39, Issue 15<br class="">Message-ID:<br class=""> <1471886901.1337427.702662641.4268E605@webmail.<br class="">messagingengine.com><br class="">Content-Type: text/plain; charset="ISO-8859-1"<br class=""><br class=""><br class=""><blockquote type="cite" class="">All, any ideas on a low power (5mA and 3.3-5V) IR beam sensor<br class="">(transmitter<br class="">and reflector) I could use in an outdoor setting? Need to count<br class="">pedestrians walking on a gravel road and the width - 30' - is too great<br class="">for<br class="">ultrasonic. Ideally, could buy the sensor components directly and<br class="">integrate<br class="">them with my data logger board.<br class=""></blockquote><br class="">Chip,<br class=""><br class="">looks like this one (https://www.sparkfun.com/products/11724) can be had<br class="">in a 10-meter version, and uses 2.9 mA average, so maybe ultrasonic<br class="">would work.<br class=""><br class="">I think decent-range beam-break is going to take some decent current.<br class=""><br class="">Alex<br class=""><br class="">--<br class="">"The theater of noise is proof of our potential."<br class="">|\ | (? \/ |?\ |V| |\ ?|? |?) | \/ | | | |?\ (? /? /\ |V|<br class="">|-||_ (_ /\ |_/ @| | |-| | | \ | /\ |^| | |_/ (_ . \_ \/ | |<br class=""><br class="">You won't find me on Facebook.<br class=""><br class=""><br class=""><br class="">------------------------------<br class=""><br class="">Subject: Digest Footer<br class=""><br class="">_______________________________________________<br class="">TriEmbed mailing list<br class="">TriEmbed@triembed.org<br class="">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org<br class=""><br class=""><br class="">------------------------------<br class=""><br class="">End of TriEmbed Digest, Vol 39, Issue 16<br class="">****************************************<br class=""><br class=""></blockquote><br class=""><br class="">--<br class="">Sent from my iPhone - please excuse the typos<br class=""><br class="">_______________________________________________<br class="">Triangle, NC Embedded Computing mailing list<br class="">TriEmbed@triembed.org<br class="">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org<br class="">TriEmbed web site: http://TriEmbed.org<br class=""><br class=""><br class=""></blockquote>-------------- next part --------------<br class="">An HTML attachment was scrubbed...<br class="">URL: <http://mail.triembed.org/pipermail/triembed_triembed.org/attachments/20160823/8522d6a3/attachment-0001.html><br class=""><br class="">------------------------------<br class=""><br class="">Subject: Digest Footer<br class=""><br class="">_______________________________________________<br class="">TriEmbed mailing list<br class="">TriEmbed@triembed.org<br class="">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org<br class=""><br class=""><br class="">------------------------------<br class=""><br class="">End of TriEmbed Digest, Vol 39, Issue 18<br class="">****************************************<br class=""></div></div></blockquote></div><br class=""></div></body></html>