Do you want precise block detection ? Use infrared

[@EsotericArctos]

You can look at Light Barrier as being the same as Infrared. Infrared is just not visible to us :). Great little video with some great information, as always. I do like the Digikeijs stuff. Compatible with so many things, and not ridiculously expensive.
Totally off topic for this video. Where do you think is best place to buy Australian model trains, as in once based on Australian railways? I kind of want to move away from British based on my layout.

[@ModelRailroadTechniques]

Thanks Brendan. Light Barriers? Do you have a link? Regarding Australian Stock: Depends on the state you live in. Australian Modeler (Auscision) have a great online store.

[@EsotericArctos]

@@ModelRailroadTechniques Light Curtain is more the correct term, but in your video Digikeijs listed it as a light barrier :)
en.wikipedia.org/wiki/Light_curtain.
The wikipedia article talks about in context of machinery safety, but the basics are there is an emitter that emits "light", in the case of infrared, it is inrared light. On the other side is a sensor that detects that light. Usually a light curtain or light barrier will send it in pulses of a certain frequency so it can be distinquished from random light around it, but in the case of detectros we use in railway, it is more a solid on as it is not as critical if the receiver accidentalyl detects random light.