Using light-sensor night lights for triggering accessories, etc.

David,

    I have been wondering about sensors along the same line.  From past construction projects, I have some used room-entry light sensors that are sensitivity adjustable.  Also, have some new (remove from units to be made manual operated by client request) sensors from the "auto flush" feature of new urinals, all on an entirely new site, nothing used, here.  Have not gotten to the attempt of trying for various activation circuits, but have many interesting ideas and options.

Jesse

Sounds like a good concept !  Keep us posted ! 

I think if you go to eBay, you can find tons of purpose-built sensors that you don't have to disassemble anything to use.  This module will directly drive a 10ma coil 5V relay.  One such relay is the TE Connectivity 3-1462039-0, 5V at 10ma coil.

ebay #: 252156585800

Driving this relay

If you "do" eBay, search on "photoresistor relay module"

There are different versions.  Most have sensitivity adjustment.  Most operate on 12V DC.  Here's one I use:

Good find Stan, I looked and didn't find the one with the relay.

How well does that resist stray light triggering the sensor?

It's the same CdS photocell as used in household nite-lites.  It has a trimmer adjustment for stray/ambient rejection.  There are versions on eBay that have the photocell soldered to the board and save you a few cents but I believe the cabled-photocell version gives more flexibility in placement. 

For the serious (i.e., "have soldering iron, will travel") DIY'er you can inspect the circuit and realize you can replace the photocell with an infrared (IR) sensor.  To the OP's idea about occupancy sensing, you could simply flood the area in question with IR energy with cheap IR LEDs and mess with home-brew ITAD functionality.  That is, this would allow running the layout in the dark using the same train-shadows-the-detector scheme. Or you can mess with colored light filters or IR plastics that pass IR energy like the dark lenses in front of IR remote control devices.

Thanks for the info John and Stan. That relay module sounds a lot simpler than taking apart / configuring a night light, well worth the few dollars.   Plus 12v is better.     Don't need 120v running under and up onto the layout, especially next to my small pond with real water!  (just kidding).   I just have a drawer full of night lights wasting space.    If I can't find on Ebay, I will look at electronic parts sites  (Mouser, Jameco, etc.).

Gunrunnerjohn - I grew up in Philly and my brother and myself would visist Hennings (around the 80's).  Seems to me my brother would drop off AF for repairs, and also purchase some.  He then later lived in Bethlehem and Allentown.   How long have you been with Hennings?  My wife is from Atlanta, so I thought I would move here to make our marriage work.   37 years now!  I miss all of the trains stores in the NE.  Not as many in Georgia.

John and Stan,

  I concur, thanks for the information concerning the ebay available sensors.  I still intend to find a use for the motion detectors I have, they are new and not encased in any hardware.  They are loose with only the wiring attached, can be placed anywhere on the layout.  have been thinking of placement under the layout, looking upward to the track overhead to detect passage of any consists.

Jesse     TCA   12-68275

Drummer3 posted:

Gunrunnerjohn - I grew up in Philly and my brother and myself would visist Hennings (around the 80's).  Seems to me my brother would drop off AF for repairs, and also purchase some.  He then later lived in Bethlehem and Allentown.   How long have you been with Hennings?  My wife is from Atlanta, so I thought I would move here to make our marriage work.   37 years now!  I miss all of the trains stores in the NE.  Not as many in Georgia.

I've been doing repairs and upgrades for about three years for them.  We are certainly in the sweet spot of the country for model trains.

I remember a hobby shop that I think was called the Train Station on county line road (or street road?),  I think at the edge of Bucks county.   They had tons of O and S gauge.

Don't know that shop, but that doesn't mean it doesn't exist.