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Re: Adding sound to my train controller

PostPosted: Fri Jun 24, 2016 6:50 pm
by Roche
Are you able to measure the voltage? The spec says 3.2 - 5.
Another thing to try - run a heavy gauge of wire from the output of your regulator - both 0V and +5, directly to the supply pins of the MP3 module, with a 0.1uF and a largish electrolytic across the supply by the module.

It seems the module uses 3.3V internally. It is suggested that a 1k resistor in the tx line (when using a serial interface) will reduce noise. I would try that in your trigger line.

On a different note, if you go to the separate power supply, if you share the ground with the existing supply, and only use the new supply for the MP3 module, you won't need to isolate the trigger line.

Re: Adding sound to my train controller

PostPosted: Sat Jun 25, 2016 1:12 pm
by grandpa jay
Roche
I tried the common ground and still had the static in the sound. I am going to try the optical isolators. This is the schematic that I am working on, any suggestions will be appreciated.
Jay

Re: Adding sound to my train controller

PostPosted: Sat Jun 25, 2016 2:41 pm
by Roche
Hi GPJ, you need a resistor in series with the drive to the LEDs of the opto-couplers - say about 220R, and a resistor going from the collector of the opto coupler to +5 of their respective supplies.

I'm on holiday for a week...

Re: Adding sound to my train controller

PostPosted: Tue Jun 28, 2016 4:28 pm
by grandpa jay
I have the sound woking with no static. I added a second power supply. My problem now is that I can not get the sleep to work. It acts like it is just stepping over it. The relay is energised when the sound is about half done. It is programmed to energize 2 sec. after the sound ends.
Jay