DIY Bluetooth sound in N scale

[bc6]

• I guess I should ask has anyone personally installed Bluetooth in N scale DIY fashion. Im sure its available professionally done but its usually expensive.

 

• Im almost 100% sure that I can do it with the parts that I have unless I'm wrong which could be the case. My inspiration for DIY Bluetooth sound was this video and of course it's in Japanese and Im not a Japanese speaker nor did I have the same parts as the person in the video. 

 

• I have a speaker, Bluetooth headset and a 2.5 watt mono amplifier can I use these items to make a Bluetooth speaker or do I need to go a different route.

 

• How would I connect the parts, Do you think the Bluetooth module can drive the speaker without the amplifier the speaker is an 8 ohm speaker.

 

 

 

Edited March 29 by bc6

[cteno4]

Are you going to battery power this? If so is the amp 5v? Looks like the Bluetooth has a usb on it so I assume it works from 5v. You can see if the Bluetooth can power the speaker loud enough but if it was a head set the speaker was a very low power one. Basically just wire the speaker output on the to the audio input of the amp and the  speaker to the audio output of the amp. If you are running both the Bluetooth and amp you may need to add more of a battery than the Bluetooth may have (assuming it has a battery).

 

try hooking the speaker to the Bluetooth and see what it sounds like. It too weak, add in the amp. 

 

you may need a little sound box or tube for the speaker as a small naked speaker is not very loud and can sound very tinny. On the tiny mp3 players I put in some of my wife’s knit toys for the grandnephews and grandnieces I’ve used tiny round speakers and cut a whole in the bottom of a small plastic bottle and glued the speaker on there pointing into the tube. Amazing how the resonance of the chamber makes a huge difference. There are some commercial speaker/soundboxes for n scale out there and I’ve see some 3d print plans for some.

 

you might look at some of the little Bluetooth speaker sets to start from. I have some that are like 1.2” dia and about the same height. Speaker might be too big but the board and battery lasts a couple of hours.

 

Jeff

[bc6]

Hey Jeff the BT module is battery powered the battery is on the other side of the module (pic below) The original speaker on the BT module is where the Black & Red wires are located. Great idea I am going to solder the Digitrax speaker to the location of the original speaker on the BT module and hope that the BT can drive the new speaker. 

 

I think I've seen some enclosures on the internet for micro speakers like the one I have. 

 

How would you power the amplifier in case I need to go that route, I guess some micro battery with a micro USB charging circuitry would work.

 

I guess Its possible to tap electricity from the BT module to the input of the amp and hope the battery can power both. 

 

Thanks for the suggestions I appreciate the help. 

 

Edited March 29 by bc6

[cteno4]

You can check the output of the lithium battery on the BT, I’m guessing it’s 3.7v. What is the input voltage of your little amp?

 

jeff

[bc6]

The input voltage is 2.0V-5.5VDC.

UPDATE:

So some news I connected the speaker to the BT module and the sound is low.

It looks like some BT headsets don't support music like my headset,\ unfortunately.

So it's off to look for a BT module that's small enough to fit inside an N scale train body and support music

it can't be that difficult right lol. 

Edited March 29 by bc6

[cteno4]

Should work then as the battery is probably around 3.7v. Just check it with the multimeter. But with both drawing from the battery may not last long.

 

jeff

[SwallowAngel]

On 3/29/2024 at 2:22 AM, bc6 said:

I guess Its possible to tap electricity from the BT module to the input of the amp and hope the battery can power both. 

Yeah, you would defo need an amplifier to power any speaker at a reasonable volume. Personally I would try to tap the power directly from the battery and put them in parralel to avoid any unexpected voltage drops.

 

On 3/29/2024 at 5:44 AM, bc6 said:

It looks like some BT headsets don't support music like my headset,\ unfortunately.

I assume you tried using some call-center-ish headsets? I personally would try using some boards meant for arduino/rasberry pi use, as documentation is much better (+ anyone who wants to recreate this has a much easier time finding the parts). VHM-314 modules look somewhat fitting, though for these you might want to try removing the connectors to save as much space as possible.

 

The whole project does look quite interesting, though I personally would opt for some stationary solution rather than trying to cram everything within a body shell. Something like the KATO Sound Station but more open source and DIY would be ideal for me personally...

[cteno4]

Yes agreed tap battery directly for the amp. If it was from a headset then yes it’s not going put out that much wattage.

 

might look at the really small Bluetooth speaker (33mm dia x 31mm tall) as they have amplifier built in. Btw I got a couple of the small speakers above to perhaps put into buildings with a usb battery for some random city noises. I’ve not torn one apart to see the board and its size and battery size yet. They are sealed up quite well. I was surprised about the sound that came out of them.

 

maybe an issue with arduino to get boards you need small enough to fit into a car. some are made quite small but many even smaller ones wouldn’t fit into a car. But there are a lot out there.

 

jeff

[bc6]

@cteno4

Hey Jeff the tap did work but I couldn't tell if the amp was working but there was no power indicator.

 

It's funny you mention getting a really small Bluetooth speaker because I've ordered the same one last night and as soon as it shows up I'm ripping it apart lol.

 

I've been researching tiny Bluetooth modules and there are a lot of them out there. The thing is that you don't want them so small that you need a 

microscope to connect them to other devices. 

 

I bumped into a company called DFRobot that I think has the board with the features that I want on it,  I'm going to research it some more before I make a purchase. 

 

 

@SwallowAngel 

 On 3/28/2024 at 9:22 PM, bc6 said:

I guess Its possible to tap electricity from the BT module to the input of the amp and hope the battery can power both. 

Yeah, you would defo need an amplifier to power any speaker at a reasonable volume. Personally I would try to tap the power directly from the battery and put them in parralel to avoid any unexpected voltage drops.

 

Good suggestion, I'll try that for sure.

 

I assume you tried using some call-center-ish headsets? I personally would try using some boards meant for arduino/rasberry pi use, as documentation is much better (+ anyone who wants to recreate this has a much easier time finding the parts). VHM-314 modules look somewhat fitting, though for these you might want to try removing the connectors to save as much space as possible.

 

Swallow I used the old-school mono headsets for cellphones, It was a Jabra headset.

You're right about the documentation. I looked at the VHM0314 and it looks HUGE lol so probably not a good fit (pun intended) lol. 

 

The whole project does look quite interesting, though I personally would opt for some stationary solution rather than trying to cram everything within a body shell. Something like the KATO Sound Station but more open source and DIY would be ideal for me personally...

 

I am almost on the cusp of giving up and going with this product from Micro Ace https://www.1999.co.jp/eng/10565150

[SwallowAngel]

Didnt know these MA modules were a thing. Though that sure is one hell of a price to pay...

[cteno4]

One issue with Bluetooth is it can be difficult to have different Bluetooth speakers respond to different outputs from your phone. I’m sure there may be a way around this someway, but never looked into it. We’ve used the Bluetooth speakers to make gogi roar on demand to mess with visitors. I had the idea of doing something similar in a structure. When I first saw the ma unit I thought it fun to send running sounds and station sounds to a train, but then realized it would get a bit tedious maybe.

 

my solution for remote sounds (other than trains) is to use a little 5ghz remote relays. You can get a little 4 channel set of relays and key fob remote for all 4. Just set the relays to momentary and use that remote closure to set off the micro mp3 player cards. These little mp3 units are about an inch square and have I think it’s 2w output to a micro speaker. You put your audio clips on a micro sd card and plug it onto the board. You can have the board play files at random or in a set order. Nice thing is the mp3 board setting are all hardwired, it’s all in how you wire it up and then set at power on. Nifty for a buck. I’ve done a number of these for toys my wife makes and quite fun! Multichannel remote relays and fobs are $10-20 for a set. I have a relay just not sat down to hook it to the mp3 board, but that just trivial wiring it to the momentary input.

 

the issue we have with the Bluetooth speaker when using at club events is only one person has control of the speaker at a time so you have to sign off with the one phone and sign on with the other phone. Also waking the phone up and hitting play could take a few seconds and you could miss the best moment to surprise someone unless you are set up and waiting. With the relay key fobs it’s easy to just punch the button and not have to fiddle with the phone. Many times I’m talking to someone when I see a visitor in just the right place to play the roar!

 

One last aside, with the goji roar I want to play with the resonance chamber as it can really make a difference in the sound. In regular small blue tooth speakers the roar sounds ok, but it’s a bit softened as they were built for music not a goji roar! When I was doing one of these setups for a humpback whale feeding and mating calls it sounded horrible from the speaker alone. Then I tried cutting hikes some different sized and height small plastic jars and wow I found the right one and the sounds were amazing out of this tiny unit. So messing with the speaker housing is really necessary to get your sounds to sound the best.

 

cheers,

 

jeff