I've done a few tests today with the MRD1 optical detectors. Didn't really want to mess with
wiring and electronics at this time, but further construction on the layout is not really possible without setting in place the infrared detectors and the wires needed. The biggest concern right now is how to hide the emitter/phototransistor pair, since both are rather shiny and bulky - bigger than half a wheel in size. Bushes or some type or vegetation would be a good choice, however there are areas where this just can't be used. For example on a parrallel set of tracks, as they are found on the PT section of the layout, where there are 2 curved tracks bordered by hills/retaining wall,with nothing on them but ballast. To make infrared detection work reliably, the emitter / detector must be placed at different hights (underbody of cars/locomotives where empty space alternates with wheels) and not perpendicular to the direction of travel (gaps between the cars would incorrectly signal the end of a train). Therefore in my case, each of the elements of one pair should be grouped together between the tracks, at a relatively low height, while the corresponding elements in the pair should be hidden in the hills/retaining walls on each side of the track).
So basically what needed to be determined was, if an obstacle is placed between the emitter/detector, for example a thick piece of paper, what is the dimension of the hole through this obstacle so that detection would work reliably. It was determined that for 1 mm, everything works just fine. Even more, if a thin enough paper is used, even if it's coloured, the infrared "shines" through. So for our example it would be possible for a small crate to be placed between the tracks, covering the 2 elements there, then 2 small holes of 1mm should be drilled on each side, and then this small holes could be masked with some paper matching in colour.
For the moment I just need to find alternatives for this crate, which might be too big to fit between the tracks.
. The search for a better way goes on...
wiring and electronics at this time, but further construction on the layout is not really possible without setting in place the infrared detectors and the wires needed. The biggest concern right now is how to hide the emitter/phototransistor pair, since both are rather shiny and bulky - bigger than half a wheel in size. Bushes or some type or vegetation would be a good choice, however there are areas where this just can't be used. For example on a parrallel set of tracks, as they are found on the PT section of the layout, where there are 2 curved tracks bordered by hills/retaining wall,with nothing on them but ballast. To make infrared detection work reliably, the emitter / detector must be placed at different hights (underbody of cars/locomotives where empty space alternates with wheels) and not perpendicular to the direction of travel (gaps between the cars would incorrectly signal the end of a train). Therefore in my case, each of the elements of one pair should be grouped together between the tracks, at a relatively low height, while the corresponding elements in the pair should be hidden in the hills/retaining walls on each side of the track).
Finally - the second half of the board is now done. Or to be more accurate, the photos from the craftsman operating the Nikon D700 are starting to reach me, since the board was just lying around here for a month or so.
