What exactly do you want to detect? If a train is on the track, or if the signal is red or green?

Teddy
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Diodentrick, auch für S88 mit Optokoppler

This thread perhaps explains it better, easier to paste it here than to retype it all

http://groups.yahoo.com/...rklinBandG/message/67751

Do this make it more clear??

Cheers again

Steve
Melbourne

Hi Steve

I do not have access to yahoo.

But I hope this helps:

[Image removed because of errors.]

Teddy
__________________________
Kontaktgleis im Selbstbau

Edited by user 25 November 2011 15:24:22(UTC)  | Reason: Not specified

What Dale has said makes sense - current finds the path of least resistance.. Would a diode (or a bridge rectifier) help here?

Hi guys, was surprised to see this thread suddenly come alive again but I appreciate the input (no pun intended)

What you are adding to the thread is largely correct, but don't overlook that I always said that the S88 will only be used (active) when the layout is in full Digital mode.

When the layout is under analogue control the S88 will be passive - ie not connected to the I.B. (or 6050 if I choose to use that).

The single thing I was hoping to achieve was to avoid having to disconnect the S88 completely and whether anyone had also faced this and found an imaginative solution.

I've been surprised at how robust the S88 actually is, and don't forget that even in pure 'digital' mode, the S88 input still can receive full track voltage as an input - ie indexing for the digital turntable or the circuit & contact tracks - you can safely feed the center rail directly to an S88 input and use that to trigger events. I'd probably tend to avoid sending an analogue reverse pulse direct into the S88 but the normal operation of the layout would not cause this.

I've pondered different options for this and have had quite a few suggestions on and off list on ways it could be achieved but some of the possible solutions require more components and circuitry that take it beyond a 'simple' solution. Once I get beyond two or three components (diodes, zeners etc) it rather defeats the purpose and really, it would be easier just to wire all the S88 inputs through a 16 pin plug & socket and just disconnect that when using full analogue.

Thanks again for thinking about it, you never know someone might get a flash of inspiration one day and stumble on something no one else has thought of.

And I also accept my need is a little unusual, most people either run analogue, or they make the move to digital, perhaps even a mix where there is very clear separation. Because this is a display layout, there may be times I'd like to run it analogue completely unattended as originally wired hence the need to be able to easily and quickly slect one or the other.

Cheers

Cookee