Wiring of my DC layout

[TomR]

Wiring of my DC layout is coming along nicely.

I have 20 switches wired to control my turnouts and automatically disable power into turnouts that are thrown the wrong way. This lets me park things on sidings and spurs.

I added an auto-reverse on a Y track I'm using to reverse directions. Very simple to wire all this because my switch panel has DC + outputs for normal and DC - for thrown positions.

I can run a train into the stub on a Wye, flip one toggle on the turnout for that Y, and run it out without flipping anything else.

I know, I know. Someday I will have to start with DCC.
http://www.w8ji.com/Model train layout wiring.htm

Tom​

 

[tankist]

i've yet to experiment with photo-detectors personally. but it seems that it is a good idea to have slight delay. perhaps 0.5-1 second shut off delay after sensor goes inactive. should prevent from jitter on the output.

several questions.
Q1,
which photo-transistor did you use (part number)?

J1,
output for optional LED. could you explain that output chain? i understand Q2, but what is the purpose of Q3? and if we already talking about output, could op-amp drive an input of optocoupler without adding transistors?

 

[TomR]

i've yet to experiment with photo-detectors personally. but it seems that it is a good idea to have slight delay. perhaps 0.5-1 second shut off delay after sensor goes inactive. should prevent from jitter on the output.

several questions.
Q1,
which photo-transistor did you use (part number)?

ASDL-6270-D22

J1,
output for optional LED. could you explain that output chain? i understand Q2, but what is the purpose of Q3?

Q3 is an open collector output that can sink fairly high current, like several lights or relays. It's just a switch.

It would be easy to add a capacitor to delay the turn on or turn off or to hold it.

and if we already talking about output, could op-amp drive an input of optocoupler without adding transistors?

I'm sure it could, through a suitable current limiting resistance. I'm playing with driving some optically trigger triacs and solid state relays, but have been busy wiring my tracks to a relay system.