I need a Nav Aid, area nav, engineer, model train fan? Somewhat OT
 

I have some ESP32 and ESP8266 micro devices which are quite small (not really tiny) and include WiFi and various analog and digital IO.

We also have a Lego train layout (think size of double garage). Obviously I need to tool up these locos to report their position on the layout and to accept commands from Central Train Control. Reporting and control via wifi is known science but I need to work out a system whereby the position of the trains can be determined, either have trains find their position and report or some remote system determine the position(s).

OK, bar code, RFID, yeah maybe but not very flexible. Camera in the ceiling, OK, but problem at a public display in a hall or suchlike.

So I need an engineer who is familiar with area navigation systems that can be scaled to the distances. Hmmm, how about those WWII era parabolic systems such at LORAN et al? Two pingers at the side and the train detects difference in travel time (phase angle). Do I need VHF/UHF or go the other way to low HF? The trains are not always in sight so that rules out infra red and ultrasonics(I think).

So, using wifi, my notion is that there are two receiver antenna off to the side of the layout. Central control would 'poll' a loco which would respond and Central would triangulate the loco position by comparing time of arrival at the two antenna. I think I might actually need three antenna, whatever.

I wonder where I can find an engineer join the dots and colour in the squares?
Thanks

If you need only to know about location at critical points, then you could use IR-emitters at various locations around the track and an IR-receiver on the train.The emitters can be hidden in the scenery rather easily and their field of view limited. Precision location near an emitter could be by placing a super magnet under the track for a few millimeters location info. For example, a train station would have an emitter at each end and a stopping point at one end have a North-up magnet and the other a South-up magnet, so the train coming North would get the South-end emitter to know to slow down and then creep to get the North-up magnet to align with the platform; the other direction would be the opposite. In between the train can count wheel turns to get an approximate value and resync on IR emitters or magnets.

The emitters can broadcast codes to identify them individually, such as is done with TV remotes. Groups of emitters can be controlled by ESP devices.

Typical trains and model trains are followed via blocks; no train can enter another block that is occupied and the train is considered to occupy the entire block.

Also in real life, US train cars are individually followed using barcodes on the cars. The rule for vandals and graffiti artists is "leave the barcode alone and we won't hunt you down and put you in prison."

Thanks for the comments.

Yes, IR 'beacons' are interesting but I put them in the category of 'fixed' markers along with RFID tags, barcodes, colored markers, things that are certainly interesting but not ideal. I should have mentioned that Lego train layouts are subject to change and rebuilding as that is the nature of all things Lego.

John

Have a look at the Ultra Wideband Positioning Module like the ULA1 https://www.haorutech.com/download/U...rManual-EN.pdf

Thanks very much, that is exactly the sort of thing I need!