Finally, the Universal MP3 Sound Board Has Arrived

I like it!

Looks good! I had questions, but the document answered them.

Very nice!  I've got recordings of a flat wheel car and flange squeal that I used for Microsoft train simulator, they're already MP3. I also plan on using something like this for ambient sounds for a Diesel facility.

Nice job, John.

Cool!  I was wondering if someone was working on something like this, guess it makes sense that it was @gunrunnerjohn.  I bought an old MTH "Freight Sounds" card that plays "Christmas music and Santa Sounds" on a random pattern.  The trigger is a little pendulum weight centered in a circular cutout of the PCB with a ring conductor.  It takes up the entirety of the boxcar interior and the sounds are...um...nominally Christmas-ey.

Using the trigger and speaker from the MTH board, this seems like it would open up a lot of extra options!

The wheel speed sensor was something I was going to ask about, but saw it mentioned in the documentation.

Looking forward to see how it plays out! (get it...plays out??)

Thanks guys, it's been a long time coming.  I'm still working on the wheel speed sensing board, that will be an add-on when it's ready.  I actually have the completed boards, but the software that looked great in the breadboard seems to have issues in the actual hardware, need time to see what's going on there.  I hope to have that ready in a couple of weeks, the holidays have kinda' infringed on my development time.

Looks pretty slick!!

Nicely done John.  The PDF file provided valuable insight into the capabilities of your product.  Maybe a future YouTube video demonstrating the application of the board would be a great way of getting the word out and generating sales.

Thank you so much for making this. I wish it existed when I was doing some of my prior projects but this will make future ones easier. Sign me up!  Would love to be an early buyer!

A video might be cool when I get the wheel speed sensor board working, that would really showcase what you can do with the unit.

I'm working on the "final" assembly of some boards.  While they come in with the basic components soldering, I still have to integrate the MP3 player and RF receiver after they arrive.  I also have to get all the cables sorted out, but I'm close.

I have more to add to the documentation, but I figured I'd get it out and let people have a peek at it, and maybe even make a suggestion or two about making it better.

Will this need a choke for use with DCS?

Very nice job John!!!  One of my sons-in-law will help me with the MP3 audio.

John,

I've been messing with something like this for two years, off and on.  Actually made a board that I used for another MP3 project (lightning and thunder) and added an RF receiver.  Never had the time, energy or interest to take to completion.  Procrastination has it's benefits!!!!  I'll be stocking up on some for use in cars and around the layout.  Great work delivering a much needed tool/toy/innovation.

Ron Lego

John when you get mine ready as we discussed i would like the speaker you showed me  me with the baffle cover over the speaker if you can tell me the part number and where you purchase it! believe the small speaker will, fit in a box car possibly!

Alan

@Engineer-Joe posted:

Will this need a choke for use with DCS?

Joe, all my products, including this one. have the 22uh choke for DCS compatibility.

@Engineer-Joe posted:

Will this need a choke for use with DCS?

@gunrunnerjohn posted:

Joe, all my products, including this one. have the 22uh choke for DCS compatibility.

Joe, we should all know by now that John thinks of everything! 

Well, that's a little generous Mark, but I did think of that issue.

I like being a generous guy!

Hmmm.  Almost bout a Bluetooth device for a project but might rethink that.

@MartyE posted:

Hmmm.  Almost bout a Bluetooth device for a project but might rethink that.

I thought about BT, but truthfully I'd have to then do the work on the phone end, that's totally out of my wheelhouse.  Given that fact, the key fob looked more attractive and accomplishes the goal of remote control without a ton more development. Also, at least for what I've seen, I'm not entirely sold on the range of BT, my Legacy locomotives have lousy range from the phone, and I've tried three different models.

I'll also soon have a transmitter product that will also interface with the RF link on this module that will allow you to trigger sounds in yet another way.  That could be connected to the Lionel SC-2 or the MTH AIU to trigger sounds from the respective remotes.  It'll use the same opto-isolation as the discrete inputs on the sound board to allow maximum flexibility in triggering sounds for transmission.

@gunrunnerjohn posted:

I thought about BT, but truthfully I'd have to then do the work on the phone end, that's totally out of my wheelhouse.  Given that fact, the key fob looked more attractive and accomplishes the goal of remote control without a ton more development. Also, at least for what I've seen, I'm not entirely sold on the range of BT, my Legacy locomotives have lousy range from the phone, and I've tried three different models.

I'll also soon have a transmitter product that will also interface with the RF link on this module that will allow you to trigger sounds in yet another way.  That could be connected to the Lionel SC-2 or the MTH AIU to trigger sounds from the respective remotes.  It'll use the same opto-isolation as the discrete inputs on the sound board to allow maximum flexibility in triggering sounds for transmission.

I was wondering if the ASC-2 could be used to trigger sounds by connecting a output to each isolated sound trigger.  Cool that you have plans for a board.  Was also thinking about using a minicommand ACC to trigger sounds with this.

This is a great product.  I'm in for two or three!

Either of those options are available, the ASC-2 or the MC-ACC would work fine.

This is very exciting!   Sorry for the delay but as a card-carrying member of the Peanut Gallery:

Power:

100-200mA when audio active. But what is it in standby (no audio)?  I'm thinking of battery applications.

10-18V AC. What determines the limits on the low end? Like your LED-light board, I think you can reach some conventional operators if we understand what's going on ~10V AC. For example, this may be a case where using a chopped-sine CW-80 or Z-1000 controller is preferable in conventional since it provide the high voltage peaks even at low throttle settings.

For a conventional application, what does the MP3 logic do upon loss of power? Is there any provision to, say, add more capacitance so the board doesn't “reset” on a ~2 second track power interruption for conventional direction change? I think it's OK for the audio to mute during power loss but the idea is the audio picks up where it left off without requiring a "new" trigger.

If you draw the 200 mA (max) from the 5V output pins, can the DCS inductor handle this much current when audio is running (itself drawing 200mA)?

MP3:

How is stereo MP3 processed? Does it just combine Left and Right? Seems a few years ago when we discussed this there was some talk of making one audio track separate so that it could be used for non-audio purposes. I suppose this depends on how your MP3 module deals with Left and Right.

How do you name the .MP3 files on the microSD card to correlate to trigger 1...5. Alphabetical, etc.

Triggering:

What is the minimum trigger pulse width?

Does a new trigger over-ride a currently playing sound? Or does it queue up triggers always finishing the first sound before starting a new one?

What happens for simultaneous triggers? I suspect your MP3 player cannot decode/mix multiple MP3 files?

If you keep a trigger active when a sound completes does the audio repeat (loop) or do you need a new “transition” from off to on?

Outputs:

Aside from tacking a wire into one of the 4 RF receiver outputs, is there any method to have one or more 4 RF outputs control/drive a relay or some other non-audio circuit?

Related to above, many RF relay modules that understand 1527 protocol operate on 12V DC.  Have you considered how to pair this module with a DC-powered wireless relay?  Just the DCS inductor and bridge rectifier (I think I see one there) go a long way!  I really believe being able to control sound AND simple ON/OFF whether lights, a motor, an electro-coupler, whatever, would make this even more universal.

Oh... and if you are looking for beta sites you know my address!

Stan I would say you shouldn’t be sorry for the delay in responding. It would take 2 or 3 days to analyze the information enough to think of all these questions and possibilities

Stan, I can always trust you to come up with a list of questions! I'd dismiss them out of hand, but they're almost always pretty insightful and to the point.

@stan2004 posted:

This is very exciting!   Sorry for the delay but as a card-carrying member of the Peanut Gallery:

Power:

100-200mA when audio active. But what is it in standby (no audio)?  I'm thinking of battery applications.

10-18V AC. What determines the limits on the low end? Like your LED-light board, I think you can reach some conventional operators if we understand what's going on ~10V AC. For example, this may be a case where using a chopped-sine CW-80 or Z-1000 controller is preferable in conventional since it provide the high voltage peaks even at low throttle settings.

The power when idle is...  I'll have to go measure it.

WOW, I overstated the power requirements, next rev has to revise that part of the document.  Truthfully, the power varies based on the voltage as the power source for the board is a switching power supply.  At 7 VDC (lowest it'll go without the 5V switcher starting to drop out of regulation), the standby power is 25ma.  Boost the power up to 18VDC, the current is 10-11 ma.  I'm assuming that with AC into the full wave bridge and 680uf cap, I'd get about the same readings.

The power with a fairly loud and busy sound file at full volume and 7VDC is right around 100ma.  Obviously, it jumps around a bit, but stays within 90 to 105ma.  At 18VDC, it's about 42-23ma average, again jumping around a bit.

For a conventional application, what does the MP3 logic do upon loss of power? Is there any provision to, say, add more capacitance so the board doesn't “reset” on a ~2 second track power interruption for conventional direction change? I think it's OK for the audio to mute during power loss but the idea is the audio picks up where it left off without requiring a "new" trigger.

The audio drops out pretty quickly at 18V, and obviously even quicker at 7V.  I didn't actually consider trying to bridge power gaps, that's a bit more challenging, not to mention would likely involve somewhat bulky components.  Anything's possible, but at some point I had to stop engineering and produce something, even it it isn't a "fits-all" solution.

If you draw the 200 mA (max) from the 5V output pins, can the DCS inductor handle this much current when audio is running (itself drawing 200mA)?

The choke for DCS is a 780ma choke, and based on my measurements, it's unlikely to see much more than 100ma, so I don't see any issues there.

MP3:

How is stereo MP3 processed? Does it just combine Left and Right? Seems a few years ago when we discussed this there was some talk of making one audio track separate so that it could be used for non-audio purposes. I suppose this depends on how your MP3 module deals with Left and Right.

The module I use is the BY8001-16P MP3 Player Module, that's a link to the description.  The MP3 player is a stereo device, but it only has one mono amplifier, so I simply convert any audio file to mono to use with the board.  It has stereo output channels that are just low power for earphones or an external amp.

How do you name the .MP3 files on the microSD card to correlate to trigger 1...5. Alphabetical, etc.

This is a place where I spent some time attempting to make the layout of the micro-SD files clear in my latest document revision.  I've updated the manual in the first post, see if that makes it clear.  It is somewhat odd, but I had to live with the limitations of the MP3 module, because I was in no mood to reinvent that wheel.

Triggering:

What is the minimum trigger pulse width?

Don't know for sure, I know it triggers on around 20 ms pulses, and I suspect less.  I use the same triggering as on the RF receiver I'm working on.

Does a new trigger over-ride a currently playing sound? Or does it queue up triggers always finishing the first sound before starting a new one?

Good question, there is actually some jumperable options on the MP3 player module to change the behavior.  There's a jumper pad to select various options, the shipped default is 010.  A second trigger on the playing track will restart the audio.  With the 000 option, only selecting a different track can interrupt the audio.

If I ever get energetic, there's also a complete serial protocol to do all sorts of things with the module, but I decided that would be a longer project that I wanted to make this.  I think it will fit into a lot of slots without having every possible option.

What happens for simultaneous triggers? I suspect your MP3 player cannot decode/mix multiple MP3 files?

Correct, it will play whichever one arrives last, even if it's by milliseconds.  It won't play multiple

If you keep a trigger active when a sound completes does the audio repeat (loop) or do you need a new “transition” from off to on?

You need a new trigger.

Outputs:

Aside from tacking a wire into one of the 4 RF receiver outputs, is there any method to have one or more 4 RF outputs control/drive a relay or some other non-audio circuit?

No, but my soon to be available RF receiver will be glad to do that for you.

Related to above, many RF relay modules that understand 1527 protocol operate on 12V DC.  Have you considered how to pair this module with a DC-powered wireless relay?  Just the DCS inductor and bridge rectifier (I think I see one there) go a long way!  I really believe being able to control sound AND simple ON/OFF whether lights, a motor, an electro-coupler, whatever, would make this even more universal.

Again, I have the relay based RF receiver to do this very task.  Obviously, for the DIY guy, adding a couple components to power the 1527 relay module wouldn't be an issue to add this capability.

Oh... and if you are looking for beta sites you know my address!

I certainly do.

Stan, you are to be commended for coming up with all these questions and scenarios!  It took John a day to reply!!   

I listed a few of these for sale in the for-sale forum, so if anyone want's one, now's the time.

Forgive me here, and I maybe in the minority. I bought a Lionel Trackmobile. yada yada yada, I blew it up. I ran it with my Z4000 and I believe I turned it up too high. Easy fix but costly to me.

I told myself I should stick with stuff that runs at 22 volts max. This product says 18v!

Now that I'm typing, I realize I swapped out my mainline Lionel 180w power with my Z4000. I had to crank it up for my MTH Bigboy. So I may have cooked the boards in my Lionel tank cars??? Urrggg.

Entirely your prerogative Joe.  If you actually really wanted to use one of these, you could easily add a couple of bridge rectifiers wired as opposed diode pairs in series with the power to solve that problem.  That would drop the voltage down to a usable range.

I was thinking of some type of sound car for my RR. Dropping down like that sounds great. I haven't decided what car I want to build yet. I see ones in small scales and like them.

I think a product like this might be ideal for a generator or mechanical reefer car?

Yep, and I'm working on a neat add-on board that will allow you to have the speed of the car pick the sound track!  You could have the reefer compressor by itself when you're stopped, and when you started moving slowly, some track sounds would mix in, and as you went faster, track sounds get louder and the compressor fades farther to the background.  Icing on the cake is you can have on RF channel triggered by the key fob that has a loading/unloading sequence, or anything you'd like.

Three left on my initial "sample" run that I posted in the for-sale forum.

If I understand the directions correctly, to trigger the sounds using the discrete input, it requires a push button type of trigger?  supply the 2-19 volts momentarily and the sound for that input will just play through?  or does voltage need to supplied for as long as you wish the sound to play?

It actually can be ANY voltage source that supplies a trigger of 2V or more AC or DC.  It just needs a momentary trigger to play the sound track.

John  we want one of these and maybe more. We want to use it for roundhouse sounds.

What do we need to do?

Bill, I sent you an email.

Have you messed around with the response time of the MP3 player when starting or re-starting a new MP3 sound?  I was thinking about the roundhouse application mentioned above...and how it relates to the freight car example in your manual.

In the case of the freight car, depending on speed you can play a different sound.  The question is how seamless is the audio when stopping one sound and starting the next sound.  So for example, the roundhouse might be playing some background sounds.  Then the turntable starts so maybe the sound changes to reflect the noisy rotation.  then the turntable stops and the sound changes to a loud latching "clunk" (or whatever) and then back to the normal background audio track.

I don't have detailed notes but in messing with a wide variety of MP3 players over the years, it seems that the memory size of the microSD card affects this gap.  I recall speculating that the MP3 processor software was written to optimize MP3 playback and file management was of secondary importance.  For example, I can imagine how large (GByte sized) cards might have slower access to MP3 files vs. smaller (MByte sized).  As you've documented the player has a rudimentary "file system".

Well Stan, you have one in your possession, so what's your take on the timing.   I haven't really done much of that, I need to source some good sounds for the freight car application to see how it does.  The transition doesn't have any loud transition issues and seems pretty fast, but I haven't quantified it.

However, your TT example is probably pretty hard to pull off seamlessly, but since it's starting the background track again, it can fade in pretty quickly without seeming to have a glitch.  Without having actual sounds and a target result, it's hard to guess at a success rate.