Layout Sound Idea

Doesn't the DCS 'Doppler Effect' do this?

I think it would work, but you would need to fade the sound from location to location.  With relays, I think you would notice the sound jump from spot to spot.

Back in the olden days when stereo first came out, we would listen to albums and try to pick out where the different instruments were in the band.  Lots of stereo "demo" records were produced to demonstrate how realistic the sound was.  I seem to recall a train or fire engine demo where the sound progressed from left to right!

Thought provoking....

Ed

I am not 100% sure if I understand this right.What kind of amp will you use to drive the speakers?If there is any interruption on the amp load (speakers) during the relay switching process you run the risk of blowing  the amp finals.One more thing,it has been known that electronic/digital equipment/circuit  boards and mechanical switches/contacts and sparks, don't go well together.I would place several speakers around the layout and provide a continuous feed.Thats what I did on my layout and it sounds great.Nick

I think it would be a little more complex than just using relays because of the two issues mentioned above, constant load on the amplifier, and the jumping of sound.  

With the insanely low prices of small MP3 modules, Amplifier modules, and buck converters for power, one could build a rolling sound car for well less than $10 in parts.  Add a small radio transceiver and you could easily add play/pause, next and previous from remote control.  

If one wanted to get really fancy with it and felt like taking the time to program things, you could use a micro-controller and an accelerometer module to have the car automatically play various sounds as the train speeds up, or slows down, or takes curves.  The parts are insanely inexpensive these days, the programing however is beyond what most folk around her are willing to bite off...most.  

JGL

I don't believe amplifier load would be an issue provided you didn't exceed the impedance rating.  However, I've tried to switch speakers with relays many years ago and there is was noticeable "pop" when the contact is made.

A couple of years ago, I was thinking about a sound system that could use the sounds directly from an engine or tender.  I purchased a small blue tooth transmitter and receiver to transfer the sound to an amp.  I wanted to use a computer system to make the sound 3D so it would follow the train.  The problem I ran into is it could work for 1 train at time but if you had multiple engines running on the layout, it would become way more difficult and expensive.  At the very least you would need a multi channel mixer to combine sounds from multiple engines to feed them into a sound system and I wasn't real sure I could get the the computer software to distinguish between multiple trains for the 3D sound.

If you wanted to use MTH's doppler effect that has been suggested here, you could feed that to a blue tooth transmitter and receiver.  It wouldn't be 3D or even stereo but the effect might be ok.  And if you like clickity clack and run your engines over 30 SMPH, you could get that too.

Tony

JohnGaltLine posted:

With the insanely low prices of small MP3 modules, Amplifier modules, and buck converters for power, one could build a rolling sound car for well less than $10 in parts.  Add a small radio transceiver and you could easily add play/pause, next and previous from remote control. 

Well, perhaps a little more than $10, but I'm working on one that I hope to make into a product.   Here's an early working prototype, but I"m going for more expanded capabilities.  This one does five sound clips of any length and uses a small keyfob RF transmitter to control playback.

Well, if you add the cost of pick-up rollers and such the price does jump up quickly, but the actual electronics are pretty cheap for a simple "play sounds when there is power on the track" type of set up.  

I see listed now, Ac-dc 5v buck converter for $1.26, TF card U disk MP3 player for $1.43, and a wide variety of fair looking speakers for $2.99 or so.  So all totaled, $5.68 with free shipping.  

Now one might want to add a couple pushbuttons with extension wires to the MP3 board to make it's functions accessible in a finished car, or as mentioned before, add a key fob or micro-processor for more functionality, or perhaps a super-cap to prevent sound from cutting out over dead spots,  but honestly the most expensive part of the job is adding the pick-up rollers to the car.  

JGL

That's only if you're able to do all the work.   If you just want sound when power is on, it's indeed pretty simple.

One of the things I want to do is have the wheel sensor so that when the car is moving I can play different sounds.  I'm also considering that I could actually trigger on the speed to change which soundtrack plays, but the transitions are still a problem.

Tom Densel posted:

...A series of speakers would be placed at intervals along the track, maybe every 3 to 4 feet.  

...As the train travels around the layout there would be several speakers under the train working at the same time playing a continuous recording of train sounds

As I understand the proposal, there is one source of audio that is selectively distributed (e.g., via relays) to a network of speakers.  Why not just send the audio over a 99 cent FM transmitter to a boxcar or other rolling stock with an FM radio.  It seems this performs the same function as a network of speakers that must be managed so that the correct one turns on when the train passes over it.  Obviously there are other wireless audio systems (Bluetooth) but 99 cents is hard to beat...

More than one receiver could be playing the audio to distribute the sound across the length of the consist. 

Stan, I question whether this would work for a majority of folks.  From the spec sheet...

I suspect that's an optimistic estimate, this is designed to be a few feet from the car's receiver.  I tried three different Blue Tooth speakers on a pretty small 50 foot track loop and none of them provided dropout-free reception for the whole trip, so I have to suspect this transmitter would have similar issues.

Agreed, 5 meters ain't going to cut it.  Those 99 cent low-cost, low-power FM modulators are of course for sending the audio from your MP3 iPod to your FM car radio so 5 meters is more than adequate. But my basic observation remains.  IF (a big if) you are able to place a wireless audio receiver/radio in a boxcar then you eliminate the point-to-multi-point wiring and relay (or whatever) switching problem. 

Here's one for a $5 that claims 100mW of output power and 100 meter range - your mileage (or meter-age) may vary!  Obviously you can run a longer antenna than 75cm to increase range...though you might need to consult a ham-radio buddy to recognize that 75cm is 1/4 wavelength of FM radio and what that even means!

There are alternatives such as inexpensive baby-monitors that transmit between rooms so well more than 5 meters, or minature Family-Radio-Service (FRS) walkie-talkies that claim 2 miles.  Yes, there are some issues with audio fidelity for various wireless audio systems which is why I first thought of FM radio.

I was also thinking the stereo capability might have some clever application by, for example, having one boxcar playing the LEFT channel near the front of the consist and a 2nd boxcar playing the RIGHT channel (with different audio) near the back of the consist.

Let the brainstorming continue! 

The stereo angle is interesting, one broadcast, two different sound streams.  However, I'm still hung up on being able to change the sound when the car is moving vs. when it's stopped.

I'll work on the "high end" system with the bells and whistles, you can figure out the "low budget" system that plays over the air.

Right.  Distributing the sound is only part of the problem.  Deciding the audio content itself is a separate issue.

The "outside-the-box" opportunity might be to imagine what could be done with track-side sensors (as opposed to in-car sensors).  Apparently the Lionel cars use an wheel-axle speed sensor.  I think I recall from an earlier thread there are sound cars that have wheel truck angle sensors to indicate going around a curve?

For example, an occupancy detector on the track is placed at a curve, then flange squeal sounds could be distributed when the train passes over that section.  While memory is cheap and you can store hours of different MP3 sounds on a microSD card, the fact remains that if you do it all in the piece of rolling stock, then all the sensors (speed, angle, direction, etc.), all the sounds (straight, curve, fast and slow clickety-clack, etc.), and the smarts to manage all this must be in each car.   Sure, Arduino microcontroller modules are just a few bucks and software is "free" but Nothing is so easy as the job you imagine someone else doing.

OTOH, if the sensors are track-side, and the sounds are stored and distributed from a track-side controller, then only one set of sounds and one controller is needed for the layout.  There are i's to dot and t's to cross for sure, but there may be advantages to breaking up the "what gets played" problem in this manner.  That's what I find interesting about the OP's concept; it may allow for a better mousetrap!

I agree it's an interesting concept, but getting sounds on a whole layout of any significant size like that will not be cheap either.  You only need sounds in a handful of cars in a consist to do some pretty realistic things with sounds.  Also, the cars can be incrementally acquired and will work all over your layout and other layouts.  The sound equipped layout just works in one location, I think that's a significant sticking point.

There is certainly room for both types of sound systems, I just like the idea of it being in the cars better, hence that's the way I'm leaning.

The Vision Line Ethanol Tank Cars sensed curves and changed the sounds to match, very cool effect.  I'm bummed they left that feature out of the later sound cars like the PFE Reefers.  It's not like they reduced the price for the later sets!

The first thing I can note is that the 99 cent nRF24l01+ 2.4GHz module is capable of sending sound, though with a 'slow' micro-controller like an Arduino it is probably not an optimal solution to broadcast sounds.  However using these transceivers to control an onboard MP3 module may work out pretty well.  

If one wanted to have a set of cars that could be placed throughout the length of a train and play various effects and background sounds responding to train speed, acceleration/deceleration, and banking/flange noise on curves that is proportional to train speed it becomes some what more complex, leaving aside the collection or recording of all the needed sound clips.  I think this could be accomplished fairly easily, with an Arduino to run the show, a slotted IR encoder on an axle to report speed, and a Gyro/Accelerometer module to detect curves and such.  I would also use perhaps two of the MP3 modules to provide overlapping sounds from the car allowing background sounds and other effects to play at the same time.  It's a lot going on, and the programing won't be fun, but even with all the functions it would provide, you're still looking at something like $20 on parts(+pick-ups and such).  You could also have one "master" car with the sensors on it and use the speed data from it and the nRF24 to talk to other cars, so that they would play the wanted sounds and an appropriate delay behind the first car.  

Another option could be to use RFID tags placed about the layout that would tell each car to 'play sound file 1234 now'  This would be more expensive, but much easier to program.  

In the end it is mostly a matter of how much time one wants to spend programing things.  The parts are dirt cheap these days to do anything we could possibly want to do.  

JGL

The acceleration around curves is pretty low, so you'd have to have a very sensitive accelerometer to actually detect curves.  Of course, Lionel did it with the VL Tank Cars, so I guess it's possible.

JohnGaltLine posted:

 

...I see listed now, Ac-dc 5v buck converter for $1.26, TF card U disk MP3 player for $1.43, and a wide variety of fair looking speakers for $2.99 or so.  So all totaled, $5.68 with free shipping.