I don't see a lot of technical messages in any of the forums that I participate in, so I usually don't post.  I like to build / make things for my own modules.  I don't have a lot of storage or running space so I make a few modules, sell them and make more.  Currently I am trying to get my N-Trak centric club to accept T-Trak modellers.  It's an uphill battle.

I am going to attempt to post a photo of two devices - the bigger of the two is an IR reflective sensor.  I use these a lot in Sumo Robotics, and was using them a bit in N-Gauge modules, but they are big (compare to some N-Gauge Kato track in the photo).  In the photo also is an STMicrosystems TOF sensor.  The TOF, when triggered measures the amount of time that a signal sent from the emitter takes to return to the sensor.  There is a processor on board of this device that turns that into a distance.  This device is very fast, you can trigger it often enough to use it as a speed detector.  (I am working up the code to do this, so that I can create a model railroad mini-radar gun.)  This device is also tiny, small enough to put between the ties of N-Guage track (or hidden looking like a tie).  I will be using these as optical sensors for trains passing a position.

If this type of thing interests people here, I can post code and files.

.michael