Recently I got around to trying out some block detectors that I have had for some time. One is a single channel model from NCE and the other a dual channel model from Team Digital. Both use the principle of sensing the current passing through one track feeder wire.
I bench tested both types and they seemed to work very well. The loco does not need to be running nor do the lights need to be on to get a detection. Just the decoder being in contact with the track is enough. The NCE version required a double loop of feed wire through the coil as per the instructions.
The outputs of the detection boards can drive small, low current 12 volt relays. I made a small relay board and mounted both boards on a scrap of 1/4 inch plywood to create a dual channel unit with dry contacts as outputs.
These are great little units for track occupancy on a DCC layout. I also tried them out with DC but they seem to be for DCC only. I do have something in mind for these and that project will be the subject of the next post.