Hello,
I am into model railway and I am currently considering time-of-flight sensors to detect train presence on tracks (HO scale). However most TOF circuits come on PCBs and seem to be mainly available as integrated circuits and have many pins. So I am wondering if any such sensor could be set at a cable's end so to be tiny enough to be placed between two sleepers/ties.
Ah i had to look it up, but then i remembered this item. (itr8307) which is used in my digital heating radiator controller. Tiny Led and photo-transistor in one package. It will require a small reflector for the object passing over it, and i think it's IR, so it won't be visible to the human eye
Thank you. So, this component is both an emitter and receiver? Also, isn't there any risk of accidental activation with ambient light?
That component is a simple reflection sensor. A TOF sensor is much more than that.
A reflection sensor is basically a switch. Yes/no reflection.
A TOF sensor is used to measure the round-trip or amount of reflected light, for exact distance.
To detect trains a simple reflection sensor is enough.
A powerful IR LED and a low sensitive sensor could make it less dependent on ambient light.
Another small reflection sensor.
Leo..
Thank you @Wawa but I think these sensors are too bulky to be inserted between sleepers at HO scale.
So how tiny it has to be? And how far it has to sense?
For example TCRT1000 is smaller, but range is only few millimeters.
Yes it contains a IR LED and an IR Photo-transistor
There might be, you would have to experiment. I have some i can see if i can do some testing for you later.
Given the context,they are railway sleepers, but you may know them as railroad ties
Deva_Rishi There might be, you would have to experiment. I have some i can see if i can do some testing for you later.
This would be very kind from you!
The thickness of a sleeper for my tracks is 2.2mm so anything higher would require to dig the track support, which I'd prefer to avoid.
Drill a hole in the track bed/base board, you are going to have to route wires anyway.
Tom.... 
It's a - technical - solution but it's not discreet at all...
Not sure what you mean by that.
I mean it’s gonna be quite visible in the scenery…
That is a cutaway view, everything is below the platform.
SMD? Like VCNT2020.
As a light sensor, I think the component in post #2 is small enough and probably easier to use (no SMD soldering).
