Sound Car

[ron045]

Just curious if anyone has ever made a sound car for the middle or end of their train to play all the wonderful sounds made by rolling stock.

It seems like it would be fairly simple by adding a HO module to a piece of rolling stock with a speaker and power with a battery or track power.

Ron

[KPack]

I've wanted to do it, but it would require new code to be written.  Basically Ring would need to create code that turned a LM into an accessory or 'slave' module that could be linked to the LM's in the locomotives.  That way the speed of the train would influence the sounds being played from the sound cars.  New sounds would need to be recorded and code written that allowed the sounds to change in pitch and frequency, similar to how the steam chuff works.

Soundtraxx did their sound car decoder years ago and I don't think it ever really took off.  I've barely seen any actually used.  I love the concept, but I just don't know how well it would be recieved.

-Kevin

[ron045]

What if you linked the two LM's as a Consist MU?

[Alan]

No varying motor load on the second LM will be a problem.

[KPack]

Correct, it will mess with the actual locomotives.  That's why I was thinking it needed to be slaved somehow, where it would be connected to the LM's but only read the speed and not be part of the actual consist.

[ron045]

Can you help me understand a little further?  There would be no motor load on the 2nd board if in a box car?  Why would the lead engine's LM care about that?  The Ring video I saw on consisting made it look like both engines want to do the same speed.  If the Lead engine does not sense the 2nd engine is catching up or slowing down, would it just keep moving as directed?

Thanks!
Ron

[Alan]

Two reasons.

First, without a motor load you cannot set stall current. When consisting, the LM is trying to balance the load between two motors and one of them has a stall current of zero.
Second, in operation the LM will continually try to lower the real motor current to raise the missing motor current thinking it is not pulling its share of the load.

I've never consisted to a LM with a stall setting of zero. Why don't you wire one up and let us know what happens. It would be interesting to know.

[ron045]

OK... I just happened to have another LM-3S-G for my next Diesel project.  Here are the results.  It would be best if I could figure out how to automatically have the sounds stop when the train stops.  If that possible?
Ron

[Alan]

Interesting how the train appears to functional normally even with a missing motor. Thanks for doing the test.

[Alan]

HI Alan,

It will work.  The only thing you will need to remember is the sound module (without motor) can not be selected as the lead loco.  In fact it would be best to always link in the sound  module (without motor) last.   All the linked loco motor sounds are tied to the sounds of the lead loco sounds (non-sound lead loco is ok - non sound still sends sound reference for other sound modules to follow). The not connected motor will not make a difference as long as it is not selected as the lead loco.

Tim

Ring Engineering Inc.