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Category : engineering   hardware

With Christmas (and hopefully a good shower of snow) just around the corner, it was time for one of my favorite events of the year: Secret Santa.

My Secret Santa match is a work mate who is a yuge fan of the Fallout series. I remembered talking with him about how cool it would be to place a Bluetooth speaker inside of an old radio enclosure and listen to Galaxy News radio.

But I decided to take it one step further. Why not get an old, functioning radio and add a Bluetooth module to it; that way we could still use it to listen to real life radio stations (even ones broadcasting on long and medium wave :o), and it would also add that vintage sound vibe to the Fallout music.

## Hardware

• Loewe T304 radio, manufactured in 1976 – 12$• 12V – 24V TP3110 Bluetooth audio amplifier board – 10$
• 220V AC – 12V DC transformer – 0$(had one laying around; a DC to DC booster would’ve been better) • 3 position double rocker switch – 0$ (had one laying around)
• Wires
• Heat shrink tubing

Note: be very careful when working with the insides of the radio and the AC – DC transformer as there are exposed AC high voltage pins

What’s really cool about this radio is that it can also receive Long and Medium wave broadcasts. I managed to listen to a station in Spain that was emitting on long wave from my kitchen.

## Putting it all together

This is the schematic of the end product.

Of course, I should’ve used the Radio’s build in AC – DC converter. But it only outputted 6V, and the Blutooth module needed at least 12V to run properly; this problem could’ve easily been solved by a DC – DC booster, but I didn’t have one on hand so I proceeded by using a AC – DC converter I had laying around from an old charger.

But, first things first.

Note: always use heat shrink tubing, as it provides structural support for your wires in addition to electrical insulation

### Fixing the antenna

The antenna was secured with a small screw at the base.

The antenna was also completely folded, and missing it’s head cap; I managed to push the first part out with a screwdriver, and the rest I pushed and pulled with a pliers. To my relief, the top had a small thread, and I put on a replacement cap from an antenna I had lying around. A good alternative would’ve been to use a small anti lock nut.

### The Bluetooth circuit

Next, I had to solder together my AC – DC 12V transformer, the Bluetooth module and the rocker switch.

Note: a single rocker switch would have been sufficient in this case, as the speaker is always connected to the radio PCB’s ground through the third wire in the middle.

### First integration test

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I was ecstatic to see it working :D.

### Closing it all up

To close it up, I had to find a place for the Bluetooth board and the converter. Fortunately the radio has a battery bay that is not connected to anything. Its wires broke off sometime in the past, as it’s datasheet suggests it is meant to be powered by 4 x 1.5V batteries.

I used my small Dremel style multi tool to make the necessary cuts and holes for the rocker switch and Bluetooth volume knob.

I also tried desoldering the SMT indicator LED used by the Bluetooth board to try to use an old red LED instead. For some reason it worked at first, but then it prevented the Bluetooth board from starting after it was mounted, so I ditched it.

I also had to cut the plastic shield in half to properly fit the transformer.

For the volume knob I had to make an indent, as the plastic was to thick compared to the length of the thread.

## The end

In the end (it doesn’t even matter) I closed it all up; together with 50 caps this will be the perfect cheap Christmas Present.

Two final touches have to be added: 2 stickers that came with the radio, one indicating the production date, and one showing the factory number.

## Appendix

This is the radio’s manual, I found it online. I’ll be posting it here for backup’s sake.