How much would a Bluetooth speaker/Raspberry Pi cost?

I really want to retrofit old 30s/40s tube radios (non-functional, of course.) with a Bluetooth capable RaspberryPi.  I like the idea that I could get the Pi to recognize reostats and buttons in the original knob locations, plus dial illumination. 

I know it will all depend on how fancy I want to get, but my ears are wrecked, so high fidelity isn't a concern.

Are there basic kits? What about compatible knobs/buttons? I know this is a deep, deep rabbit hole. I'd like to get good enough to possibly turn this into a future side gig.

Most people would choose the easy button which is to install a Bluetooth amp board, powering the speakers as an all-in-one solution.   This will require a power supply, and since that's there,  you can power the illumination directly from that.  Most old radios weren't exactly RGB illumination. The lights were on or off.

https://m.youtube.com/watch?v=YgTq06V-K0A

Following. 


I was going to do something similar about a decade ago for my vintage business, but my job jar has been overfilled ever since.

Oooo, I've done this! The advantage a Pi has over the Bluetooth option is the ability to use AirPlay from Apple devices or to do other things at the same time. The downside is setup on a new network and sketchy Bluetooth capabilities on Apple devices. Also, they don't do analog inputs without a bit of extra hardware that will cost $5-10.

Peerless Reproducer. Uses the original 1930's speaker. I needed a small audio transformer to get the resistance into the right range. Runs off a $10 Pi Mini Zero W with a $17 HiFiBerry Miniamp. Uses Shairplay to act as the Airplay target. Has a vintage sound despite the software equalizer, but is perfect for Glenn Miller. All mods are reversible.

GE F-63. Same Pi Zero W, same Miniamp, same Shairplay, speaker is a car speaker from Best Buy, small power bar. The light works when the radio is playing and the knob on the left turns it on/off. Good sound. The complete tube setup is still inside, fully reversible. This is my bedside radio.

Inside before final wire management. I have the original speaker stashed away safe.

The big one, a Majestic 91. $45 Pi 4, $70 60W HiFiBerry, 12" speaker taken from a guitar amp (Peavey blue marvel), suitable power supply and internal power bar. Light works when the radio is playing. Surprisingly good sound quality. The lid is now hinged and the upper half of the cabinet can be used for storage. Or, in my case, a Wifi repeater. I have also used this as a Pihole and a Plex media server with 4 TB of storage stashed inside. I never got around to hooking up the knobs. This was a one-way trip for an unsalvageable radio.

My wife uses this one all the time.

In reply to Keith Tanner :

Got most of that except Airplay target. Can I assume that's what your device,  in my case a Galaxy S8, sees and connects to? I'm a total hack, btw. Its best to talk to me like a 5 year old/complete idiot. I am not a programmer.

Let's say the radio shell I use is totally gutted. What would be solutions to lights and controlls. Ideally, I'd like a manual volume control and possibly a forward/backwards skip feature.

Airplay is a way for Apple devices to stream audio to each other over a network. Better sound quality than Bluetooth and since it's over the network you don't need to worry about range. But it's Apple-only. 
 

Non-Apple Bluetooth is easier to deal with but I have no experience in it. I can put together a step-by-step for you on some of this, but you are in danger of learning :)

The comment about analog inputs had to do with using the volume knobs from the radios. 

Keith Tanner said:

The comment about analog inputs had to do with using the volume knobs from the radios. 

Thats what I'd like to try to do. Are you saying the original factory controls can be used? I'm definitely up for a step by step. Much appreciated.

https://m.youtube.com/watch?time_continue=695&v=5eY-CStPHVc&feature=emb_logo

This project uses a rewired tube chassis with 2 tubes and a jack for a MP3 player input.  No reason you couldn't use a Pi in place of the MP3 player. 

The cool part of this one is that the original volume and tone knobs still work.

A WAG for cost.  A Pi 3B 32gb new is around $100.  Don't know what a sacrificial radio would cost - $25 - $30?  Other materials, tubes, sockets, etc. $25?  I would guess under $200.

There are a number of bluetooth amp boards on amazon- I would expect you can find one that has external inputs for volume and whatnot- but there are some that have a simple knob to control it.  So it would be a project to mount the board so that it points out where you want it.

And this can be a real business- there are quite a few of these for sale on Etsy.

Just found a pretty inexpensive board from a source I've bought from before- https://www.sparkfun.com/products/17951

A little easier to surface mount to an old radio, I'd think.

CJ said:

A WAG for cost.  A Pi 3B 32gb new is around $100.  Don't know what a sacrificial radio would cost - $25 - $30?  Other materials, tubes, sockets, etc. $25?  I would guess under $200.

You need to shop around. A Pi 3B is $35 :) 

The question here is "why a Pi?" They're great little computers but that's not really what you need and that brings extra complexity in setup and use. A BT amp is the easy button - that SparkFun unit Alfa spotted is perfect if it sounds okay. Don't forget to budget for a power supply that can keep up. Learn how to solder in wires to your original controls, fairly straightforward but may need an extra inline resistor. Then you can concentrate on the aesthetics. 

Radios will vary. I paid $12.99 shipped for the Peerless (it's just a speaker, not a radio). The GE was $79. The Majestic was an aesthetic wreck and free. You'll learn that certain styles are sought after by collectors and a lot more expensive - and that they're all heavy and expensive to ship. Time to start hunting estate sales and Craigslist, that's where the deals are. 

How do you determine the viability of the volume switch? Test the resistance range?

What knobs do you want?  FM tuner is actually hard to find in speaker kits anymore :(

The rest you could get pretty easy without any 'smarts'.  https://www.parts-express.com/Dayton-Audio-KAB-230v4-2-x-30W-Class-D-Audio-Amplifier-Board-with-aptX-HD-Bluetooth-5.0-325-503 for example.   Parts express has a few kits with remote volume knobs.  You can also do remote mic, power on/off, in use light, etc.

I really want to build my own speaker/radio setup, but every time I look it seems like the absolute cheapest I am going to get is $100 and I can buy something off the shelf that more than meets my needs for way less.

In reply to ProDarwin :

Oh, most definitely. I was half tempted to gut a Bluetooth speaker rig from $5 Below. But trying to adapt that to an old cabinet with the fratures I want seemed like a quick way to a $5 paperweight.

What I'm looking to do:

1. Volume/on-off knob.

2. Manual forward/backwards skip (where the radio tuner originally was)

3. Illuminated radio tuner back glass.

4. Bluetooth capable

That's all I'd really like to do. I can solder. I just need a good diagram, and component list and I'm good. If all that's possible without and computer ir programing, even better.

I'm doing this simply for the vintage looks.

Hmm, everything on that list is easy except #2.  I havent seen any simple board kits with backward/forward buttons on them.

I suspect it could be accomplished with an Arduino though which would be preferable over a Pi for this type of application.

I can definitely live without #2. Realistically, I rarely use it on the speakers that have it.

I was just thinking of what to do with the second knob. Maybe separate the on/off switch and the volume?

Not that I need anymore projects that I will probably never get around to but this is cool.

This is super cool. I want to attempt this. 

#1023 thing on my todo list.

Appleseed said:

How do you determine the viability of the volume switch? Test the resistance range?

Basically, yes. 

Depending on what a tuning knob is attached to, you might have trouble turning it into a rotary encoder (a knob that spins endlessly in both directions and just reports "I moved x steps" to the computer) or a jog dial (more commonly used for prev/next). Heck, tuning knobs are often attached to physical tuning apparatus and aren't potentiometers (normal volume knob type). So you might just have to leave it alone.

I'm not seeing any reason for an Arduino or Pi here. You'd use them if you wanted something more complex (I had a plan for a radio that would start playing vintage radio serials when you turned it on, tied to a specific time of broadcast - the Pi could handle that well) or if you wanted something not bluetooth (ie, my AirPlay) but for just being a big inconvenient cool looking bluetooth speaker they're the wrong choice.

BTW, my first attempt at the Majestic used a small amp and bluetooth. It didn't work out because I chose the wrong amp and blew it up - tubes, man, they're weird - and then went down a much more complex but interesting rabbit hole. Had it worked out, I'd probably have far fewer wiring projects on my workbench and no media server but it would have been done sooner and cheaper. So I'm happy that didn't work out for those reasons, but had I been stuck on the original brief of "bluetooth this big old radio" it would have been easy.

In reply to Keith Tanner :

When you say "it blew up"- what do you mean?  Did the amp fail because you were driving it too hard?  or the speaker blow?  

The one thing that doesn't make me pause is how inexpensive the 50-100W BT amplifier boards are.  So if that happens, not a big deal.

I don't know if I will ever get to one of these- as I would like to find the box first.  But it would be fun.  

It was a tube thing, I amputated one and used the heater circuit to drive the light on the front of the radio since I only needed one channel. Something something balance push pull or something, the amp committed suicide because the tubes had a codependent relationship and one of them wasn't there. Like I said, it was basically a matter of choosing the wrong amp. Those little boards like the one sold by SparkFun are a much better idea.

In reply to Keith Tanner :

Aaahhhh.  You were reusing what was there.  Got it.  That would be way over my head to even try.  

I wasn't, it was a cheap Amazon amp. But I decided I wanted tubes because it was a tube radio, and I didn't know what I didn't know and broke it.