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Adding sound to LEGO trains

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  • Member since
    July 2010
  • 11 posts
Posted by Legoboy3998 on Thursday, January 20, 2011 12:19 PM

DigitalGriffin

Good luck.  Let us know how it works out. :-)

So I finally had some time to try it out.  IT WORKS :)  since all I need to sound module to do is provide sound, all I did is connect the red and black wire to my + and - wires from my onboard battery.  This gives to module power to operate the sounds.  I made the connections temporarily to test to see if it would work.  Now I will have my Uncle (a model railroader) solder the wires perminently.  Thanks to all for your help and advice.

Sal

WFB, WI

  • Member since
    December 2004
  • From: Pa.
  • 3,361 posts
Posted by DigitalGriffin on Saturday, December 18, 2010 5:52 PM

Good luck.  Let us know how it works out. :-)

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

  • Member since
    July 2010
  • 11 posts
Posted by Legoboy3998 on Saturday, December 18, 2010 5:37 PM

According to the MRC module info, it is designed to run on a variety of systems, including DC and Battery powered.  To get around the PWM problem, the LEGO system has built in circuits to convert the power back to normal DC where the motor connects to allow for motor speed control of normal DC motors (i.e. increase voltage increase speed, I tested this with a multimeter).  So it sounds like my only issue may be the Power required and according to the info it looks like it requires only 1.5 amps.  So I think Ill temporarily connect it and see what happens.

Thanks for the Help.

Sal

WFB, WI

  • Member since
    December 2004
  • From: Pa.
  • 3,361 posts
Posted by DigitalGriffin on Saturday, December 18, 2010 4:41 PM

technically speaking

yes you could do it.  But it wouldn't work very well

Your lego module puts out PWM signal.  You could attach the outputs to a simple inductor/cap circuit which will turn it back into varying DC voltage (rough appoximation)  The decoder in turn would run off that.

BUT

Most DCC sound decoders don't start moving until 8 volts.  And you only have 9.  Plus you would have to supply up to 14 watts.  That's a lot for a little lego decoder.  And you have to be very careful with your PWM->DC circuit

It would be better if you used something like Aristo G wire instead.  Sheldon (Atlantic Central) should be able to help you out there if I remember correctly.

 

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

  • Member since
    February 2002
  • From: Quad Cities Iowa
  • 149 posts
Posted by trainman6446 on Saturday, December 18, 2010 3:23 PM

I dont think this setup would work. A dcc decoder on dc needs clean dc power. Your Lego system dosent use a clean power supply.

  • Member since
    July 2010
  • 11 posts
Adding sound to LEGO trains
Posted by Legoboy3998 on Thursday, December 16, 2010 9:45 AM

Ok heres a different one.

I want to wire a MRC on-board sound Module with transmitter into a LEGO locomotive I built. The locomotive uses LEGOS Power Function system and is powered by a DC battery wired to a IR receiver. The output of the IR receiver runs to the motor. The LEGO system has 4 wires, 9v, 0v, C1, and C2.  C1 and C2 are motor control wires, always have full voltage and use PWM to control motor speed.  The LEGOsystem has LED lights which use a bridge rectifier so that if connected in parellel to the motor would get brighter as the motor speed up. The sound Module has a NMRA standard 8 pin plug. I want to wire the module so the bell and horn and prime mover sounds work?  Does the Prime mover sound eed constant voltage and use some other method to increase and decrease the rpm sound or does it use voltage changes to change the sound?

NMRA standard 8 pin plug:

http://mrr.trains.co..._01.ashx?mw=900

MRC module info:

http://www.modelrect...000-1001ins.pdf

If there is any other specific info that would be helpful let me know and Ill try to answer any questions. Hopefully someone can help thanks.

Sal
WFB, WI

Tags: MRC , sound

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