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Last post 11-21-2009 4:37 PM by cacole. 8 replies.
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11-04-2009 12:02 PM
Offline Robert Frey
Not Ranked
Joined on 08-08-2006
Greendale, WI
Posts 23

A very simple IR Train Sensing Circuit.

On page 20 of the December 2009 issue of Model Railroader is a Correction to the IR Train Sensing Circuit published on page 64 in the October 2009. In general, the 470 Ohm and the 470K Ohm resistors got reversed.  This circuit problem was as figured out in the DCC Forum http://cs.trains.com/trccs/forums/t/160848.aspx  A very simple IR Train Sensing Circuit is using just one IR Sensor, one Transistor and one LED is showned in the following picture.  It can sense the tip of your finger more then 1/2 inches away. 

Robert Frey

 

 
11-04-2009 1:01 PM In reply to
Offline rxanand
Not Ranked
Joined on 11-24-2005
Teaneck, New Jersey
Posts 93

Re: A very simple IR Train Sensing Circuit.

Using IR to sense train movement is also an interest of mine. I have found an inexpensive two component solution to this problem. Please check out this article on my web site. Edit: Not sure why the link did not show up. Here is the link: http://www.coralfringe.com/IRDetection.html
11-04-2009 5:27 PM In reply to
Offline Robert Frey
Not Ranked
Joined on 08-08-2006
Greendale, WI
Posts 23

Re: A very simple IR Train Sensing Circuit.

My Digi-Key Part Search: http://www.digikey.com/

QRB1114 is $1.51    MPSA27 is $0.47   511-1250 is $0.27  The picture is of a Fairchild Optoelectronics Group  QRB1114 IR Sensor that is mounted under my HO Track. 

Robert Frey

---------------------------------------------------------------------------------- 

Article by Rangachari Anand  October 26 2007

Three albums of photos from the streets of Hyderabad in India.

http://www.coralfringe.com/IRDetection.html

 

His experiments in using IR to detect HO train occupancy.

IR Detector is S471FE  Sharp Microelectronics     Digi-Key Part is 425-2069-5-ND             

IR Emitter is QEC113 Fairchild Optoelectronics Group  Digi-Key Part is QEC113-ND

“A cost-effective way to utilize IR detection on a train.”

 

 
11-04-2009 7:24 PM In reply to
Offline larak
Top 500 Contributor
Joined on 10-03-2005
Ulster Co. NY
Posts 1,187

Re: A very simple IR Train Sensing Circuit.

rxanand:
 

How's that?

11-05-2009 4:22 PM In reply to
Offline Robert Frey
Not Ranked
Joined on 08-08-2006
Greendale, WI
Posts 23

Re: A very simple IR Train Sensing Circuit.

Three albums of photos from the streets of Hyderabad in India by Rangachari Anand

 http://www.coralfringe.com/  

He also made reference in his article to IRDOT detector from Micro Mark.“Standard IRDOT-1 mounts to underside of track base board.Emitter/detector pair installs through hole drilled between ties. Trains passing overhead reflect the beam and trip the circuit.”

http://www.micromark.com/SearchResult.aspx?deptIdFilter=0&searchPhrase=IRDOT

“IRDOT-1DEW with extended wire-leads has separate emitter and detector attached to 18 inch long leads for mounting in tight spaces or for use as a beam splitter (trains break the beam and trip the circuit). Features a 4 to 5 second delay on detection drop-out so that indicating lights don't flicker as a train passes over the detector.”
11-05-2009 11:12 PM In reply to
Offline willy6
Not Ranked
Joined on 01-27-2003
Ridgeville,South Carolina
Posts 674

Re: A very simple IR Train Sensing Circuit.

www.logicrailtech.com I like the stuff they have and simple.
11-20-2009 10:11 PM In reply to
Offline Robert Frey
Not Ranked
Joined on 08-08-2006
Greendale, WI
Posts 23

Re: A very simple IR Train Sensing Circuit.

Yes, Logic Rail Technologies does make easy to use Optical Detectors.  The Optical Detector OD-1-IR for example, utilizes an infrared emitter and detector between the rails. When the beam is not reflected the OD-1-IR will activate its green output.  Use this version under any layout lighting condition.

http://www.logicrailtech.com/sigani.htm 

 
11-21-2009 1:59 PM In reply to
Offline maxman
Top 500 Contributor
Joined on 02-15-2008
Posts 868

Re: A very simple IR Train Sensing Circuit.

Robert Frey:
Yes, Logic Rail Technologies does make easy to use Optical Detectors. 

Quite a difference in price between this commercial product and your two designs isn't it?  Will your design work just as well?
11-21-2009 4:37 PM In reply to
Offline cacole
Top 25 Contributor
Joined on 07-23-2003
Sierra Vista, Arizona
Posts 8,601

Re: A very simple IR Train Sensing Circuit.

By substituting a 2N3903 transistor for the more expensive and hard to find MPSA27, I have gotten Robert's circuit to detect up to 2 inches away.
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