Retro Radio With a Hidden Secret! Old School Style With New School Parts.

Updated a 1930's cabinet style radio to play music of its era and simulates tuning radio stations. Oh, and it also has Bluetooth.

I started collecting vintage radios at one time. Mainly because I think they are cool and they usually go for pretty cheap. I got this one for free from a family member. It was in pretty bad shape. I had plans to restore it back to original but then I realized that it only tunes in AM station and would be of little use. But I love the way it looks with the tubes, soft lighting, big dial, and wood cabinet. 

So! I decided to make it play music of its era and keep it looking original. But, also added new functionality like Bluetooth audio, new amplifier, and new speakers. But they are all hidden under the old electronics to not ruin the old school vibe.

The coolest part is that it now simulates tuning in a radio station from the 1930's!

This means, when you turn the tuning dial, you hear radio static as it goes to the next song just like it did back in its day. To do this, the Raspberry Pi is playing two MP3s at the same time to create the "tuning" effect. One being static sound and the other being the Mp3 music. When fully 'tuned' to a station, the static sound is phased out.

Because I had extra knobs on the outside. The tone knob (4 position selector) now selects between 1930, 1940s, 1930s Christmas, and War of the Worlds radio broadcast by Orson Welles.

The video has more detail on exactly how it works. I hope you will enjoy it. Please let me know of any questions or comments. I think these old radios are a work of art! This one will now have many more years of life in it, as long as that Raspberry Pi keeps going. 

Part 1:

https://youtu.be/jcpF9YZYJf4

Part 2:

https://youtu.be/_pkb2qcJ-P4

If you enjoyed that video you may also enjoy my channel. Please check it out.

https://www.youtube.com/c/CodeMakesItGo

1. Obviously you will need a vintage radio. I really liked the cabinet style because a rarely see them. More popular are the smaller toaster oven size radios. Whatever radio you choose from this era, it will most likely have plenty of room for you to hide your new electronic inside.
2. Next you will need the brains of the operation. The Raspberry Pi. I chose this because it easily runs python code, has plenty of storage and has audio output. Also it is a fairly cheap computer. I used a Pi 2 but any version will work, this project is very lite work for the Pi.
3. For the amplifier and Bluetooth, I bought the Pyle PFA330BT. This is a 2 channel 90 Watt amplifier with audio input and Bluetooth Wireless capabilities.
4. Because the original speaker was deteriorated and falling apart, I bought 2 8" speakers at 4ohms. Yeah, this 1930s cabinet has bass now.
5. To control the new lights and the amplifier from the Raspberry Pi, I used these very inexpensive relays. I needed 5 of them so I bought a 4 pack and a single.
6. Finally, I bought new dimmable led lights so I didn't have to supply power to the original incandescent light bulbs. They have a soft yellow glow so they look the same and put off near zero heat.

Typically with these old radios comes a lot of old dust and cob webs and whatever else decided to nest in them. I took a long time cleaning my radio up and even took the cabinet to an antique restoration professional that specialized in cleaning old wood figurines in churches and museums.

The reason I took it to this person is because they take special care in restoring the wood but without removing the character it collected over the years. Meaning they really like it to show age and will not do a full show room style restore. Just a really good cleaning. Cost me about $150. Obviously, you don't need to go this far, just telling you my story.

Yeah that's right more cleaning. Except this time I was doing it specifically for the electronics and the metal frame holding the electronics. So much of the electronics were corroding, rusting, and even some of capacitors were leaking. So I had the parts sand blasted to get all of that gunk off of the metal parts and repainted them.

Next thing I did was sad. I assembled the radio hardware without the original circuits to make room for the new equipment. I wanted the radio to look original, so I kept all the external components but all the internals were now gone. Here is a picture of the before and after. It hurt to cut out all of these components but most if not all of them were bad. Even the cloth wrapped wire was falling apart.

First step was to see if I could control the lights on the radio. To do this, I connected the relays to the Raspberry Pi outputs as indicated on the attached chart. Then I connected the lights to the relays and ran a small Python script to test if the lights would work. I just used the same 5V power supply going to the Raspberry Pi to power the LED bulbs.

At first the LEDs were too bright, so I added some resistors inline to reduce the brightness. I think the end result looked great. And I could control them through the Raspberry Pi too!

With the audio out on the Raspberry Pi, it is time to ensure you can hear something because the step after this is to disassemble the amplifier to automated the button press and you want to make sure you went into the next step with a working system.

Connect an audio cable from the Pi to the Pyle amplifier and switch it to audio input mode. Also be sure to connect a speaker. Next, load up the Raspberry Pi with MP3 files. I chose music from the 30's and 40's. I also made a directory for 1930s Christmas music and War of the Worlds radio broadcast by Orson Welles. Because, that's kinda cool right? Also you will need to load a Mp3 with radio static sounds.

Next I installed 'omxplayer' on the Pi to play the MP3s. If you hear audio, great! Rock out a bit then go onto the next step when you are ready.

As you knew from the start, we would somehow have to control the buttons on the amplifier to turn it on, and switch from audio input to Bluetooth mode. The Volume knob was easier, I just extended that to the outside of the cabinet, so it is still manually controlled.

Again using the diagram in step 4, I connected the relays to control the buttons on the amplifier. This was easily the hardest part of the build because I had to de-solder the switches and buttons. That is never easy for me. The Bluetooth switched used 2 relays alone and the power switch used one.

If you can manually trigger the relays, ensure the amplifier is still working by testing with step 5 again. If so, the radio is basically done. The next part is just for the added authenticity of tuning in a radio station. But technically you could stop here and just have the tuning dial not be functional, the radio would just loop through all of your Mp3s you loaded on the Pi.

So if you thought the last few steps were difficult then this one will be a doozy. We are going to use optical sensors to detect the position of the tuning dial. Because all radios are different, you will have to figure out a way to make this happen on your radio. But usually, there is a shaft that you can mount a custom tuning dial on. Once you figure out how to mount your custom dial to the shaft then you will need to find mounting locations for the optical sensors. I mounted mine 180 degrees apart from each other. So...let me review that again.

The idea is that this custom dial will indicate when to play music and when to play the static sound. I printed a small wheel that would mount onto the original tuning shaft. I then cut out clear plastic circle from a strawberry container and glued it onto the wheel. This is now the new tuning dial. Half of the custom dial operates the static optical sensor, when to play and not play the static sound. And the other half of the dial operates the music optical sensor, when to play and not play the music. You can see in the picture that the little black marks and the larger black marks are almost opposite of each other.

As indicated in the line graph, the static optical sensor has a small section where it stops playing and the music sensor has a larger section where it is playing. This is how we simulate tuning into a station. You can mark on the custom tuning dial the optimal locations for these marks according to where you mounted the optical sensors. As you can see, my mounting location was not perfectly 180 degrees from each other.

Yes, I know this part is crazy but don't give up. It took me more than a couple tries to get this to work right. Also, all radios are different so it is difficult to have specific instructions on how to do this step. But as long as you have the general idea how it works, you should be able to figure it out for your radio.

Next connect your manual inputs to the Raspberry Pi as indicated in the diagram in step 4. For a switch like the power, I have one side going to the Pi input pin and the other going to ground. This is why these inputs are set as pull ups, like GPIO 16.

Next, load the python code and ensure you have the proper Mp3 files in the same directories or modify the code to fit your setup.

It may take some readjustments and testing of outputs and inputs, but everything should be working at this point. Again, make sure you have the speakers connected....

For mine, I used the original wood to cut out a new template using MDF board. Then cut out two circles for the 8" speakers. I also re-upholstered the speaker grill because the original material was falling apart.

Finally put the finishing touches on. I printed new knobs and fixed the cracked display glass. This was a fun build and allowed an otherwise old junked radio to be brought back to life that people really love again.

Please check out the video if you haven't already, it has more detail on the build. If you got this far thanks for reading!

Leave a thumbs up!

Please leave a comment, love to hear your feedback and thoughts.