I just found this old Soviet transistor radio and it was in not working condition, so I decided to convert it into something useful instead of throwing it out as an e-waste object. I searched a lot about the topic and I tried to create a Bluetooth speaker from it.
I'd like to show you how I saved and gave a second life to this guy! Hope you like this idea and after this instructable, you can upgrade and reuse your radio or anything else!
Let's get started!
Step 1: Find a Cheap, Not Working Radio!
You can find old radios easily! Just visit any local second-hand market or flea market. I'm pretty sure you'll find some not working, broken or unused radio. You don't have to use radios. You can convert anything into a Bluetooth speaker that worth to prevent. Old suitcase, PVC tube, old TV, food box, old monitor, or anything you find!
If you created something, feel free to share it in comments! :)
Think globally and save these treasures! Hope you can find something to reuse with the help of this instructable and minimize e-waste at the same time.
Step 2: Parts, Materials and Tools
I usually buy electronics parts from eBay or local stores. I inserted links to the parts, hope still work well. If the links are not working then try to google the name of the part.
- Old, not working pocket radio or anything else
- Bluetooth 4.0 APT-X amplifier board (Bluetooth 4.0 C SR8645)
- 5W 4ohm 1" speaker (1" inch 4 Ohm 5-10W Full Range Audio Speaker)
- Charging board (Micro USB charging board 5 V 1A Li-ion)
- DC-DC adjustable voltage step-up board, optional (5V to 24V 2A)
- 3.7V li-ion battery (11 00mAh Li-Po) but you can use any li-ion battery from your old phone for example Nokia BL-5C would do the job.
- Microphone, optional (4x 1.5mm Electret Condenser Microphone MIC capsule)
- 4 pcs Tactile buttons (6x6x8mm Tactile Pu sh Button Switch)
- 4 pcs Switch caps (Black Round Switch Cap Hole diameter 3.2mm)
- 2 pcs 3 mm LEDs (green, red)
- 2 pcs 1 kOhm resistors (for LEDs)
- 4 pcs M2.5x8 screws
- 4 pcs D2xL5 wood screws
- Hot glue
- Glue (Loctite)
- 6 mm thick plywood
- 4 mm thick wallboard or plywood
- Wires (any UTP cable is good)
- Heat shrink tubes
- Solder station
- Hot glue gun
- Wood saw
- Rotary tool
- Utility knife
- 40-41 mm hole saw
- Drill bits ( D3, D5, D9)
- Plastic bags for small parts
Step 3: Safety First
During the process please use safety glass and half-face dust mask!!
Small flying particles can damage your eyes!
The mask protects you against unhealthy dust!
Step 4: Clean and Repair the Radio
Clean the outside of the radio with some alcoholic liquid and cotton swabs or cotton pads carefully.
If there are any broken or cracked part, try to fix it with super glue.
Step 5: Disassembly
It is quite simple! Just take out the two screws on the backside of the radio. Screw off the holding screws on the circuit board and remove the speaker as well. Collect the small parts in plastic bags or any other container for the reassembly.
Then desolder or cut the components from the circuit board. Please use safety glass!
Half of the circuit board is not needed because we use a new speaker. So I cut down the unwanted part with a rotary tool.
We need the volume wheel which will be the ON/OFF switch of the Bluetooth radio!
This Signal-601 radio has a mechanical clock which typically stops after a few years. I wanted to have a well functioning device so I took it to a professional clockmaker. He repaired it for $7.
* The desoldered original electronic parts can be reused by a professional who repairs old radios or old electronic devices. Transistors, speaker, resistors, capacitors etc. Try to find someone and give these parts to him. Maybe a collector is interested in your desoldered parts. Maybe you can sell it on eBay...
Step 6: Speaker Mounting Plate
First of all, measure the radio and try to find out which speaker size would be the best for your radio. Every dimension is important. Usually, suppliers publish the height and diameter of the speakers on eBay or Amazon so you can compare it with your possibilities.
Of course, I ordered a wrong speaker at first, so it didn't fit ... :) Then as a new speaker, I used a 1" 5W 4 Ohm Harman/Kardon speaker.
Because of the original speaker has larger diameter I made a speaker mounting plate from 6 mm thick plywood. (You can see the drawing of it.) Measure your radio box and try to cut a suitable wood plate or you can use simply hot glue around the speaker to fix it to the box but this wood plate gives some extra support for the radio box and the sound quality. The smaller the radio box the harder to find a good speaker and mounting plate.
To make the plate you need some extra tools such as handsaw, rotary tool and hole saw.
I wanted to use the metric inserts of the plastic radio box in which the speaker was originally screwed, so I measured the thread and finally, I used 4 pcs M2.5x8 screws to lock the mounting plate to the radio box.
If you don't have these inserts then simply use hot glue to fix the plate or the speaker. It was just fancy to use the original holes for me. :)
Then the new speaker can be screwed onto the wood plate.
Don't left any rustling piece between the speaker and the housing! That would be really annoying.
Step 7: Preparation of the Back Plate
Before starting the preparation try to find places for buttons, USB charger, battery and check the free places and possibilities. Use some marks on the surface. Make sure that you will be able to close the radio box if you put everything inside.
The Bluetooth amplifier used in this project has 5 function button such as Play/Pause/Phonecall, Vol+, Vol-, Next, Previous. I skipped the Prev. button because Next is more useful when one listen Spotify or any other music list. But you can use all of them if you would like to build a full extra speaker.
I decided to place the buttons on the top of the radio. The tactile button caps has 8 mm diameter size so you have to use 9 mm or 10 mm drill bit. I recommend you to use these bits by hand because the drilling machine can melt or break the plastic. Start with 3 mm diameter and increase the hole size step by step. That's why you can see D3, D5 ad D9 bits in the tool list. You can find a detailed drawing for one possible pattern. But be creative and try to find a pattern suitable for your project. A circular pattern would be an impressive solution maybe (if you have enough place for that)
Cut 9x15 mm rectangular piece from a 4 mm thick wallboard for mounting the tactile buttons and glue it under the predrilled holes. Then drill 3-4 mm size holes onto the wallboard with rotary tool. Try to find the center of the predrilled holes. Check the size with the tactile buttons continuously, you should be able to push it freely. Before assembling buttons with caps you should deepen the holes with D9 drill bit so that the caps coincide with the top surface.
You can use simply the tactile button shaft without any cap and then you can skip these boring steps. But... it looks far professional with button caps... :)
If it's done, then assemble the buttons with caps by pushing them carefully together as you can see on the pictures. After it, you can glue the buttons with hot glue but pay attention to the free movement of button caps.
The last modification step is cutting the place of micro USB charger with rotary tool. Use the smallest bit (or D3) you have and check the shape and size continuously.
Step 8: Electronics
You can see the circuit diagrams above. One for the whole system and one for only the Bluetooth amplifier board.
Before putting everything together I soldered subparts together like the:
1. Charging board with green indicator LEDs.
This LED will light up when the charger is connected to micro USB charger.
I used the original jack socket for mounting the LED. I was very happy to find that socket! :) Anyway, it's a Bluetooth speaker so we don't need a jack for AUX connection... So the charger board can be glued in. A micro USB cable can be useful to hold the module in position. Don't glue the connection holes!
2. Red indicator LED for ON/OFF states. Use heat shrink tubes to avoid contacts between the legs of LEDs. I placed this LED into the hole of original antenna.
Final wiring is a little bit challenging story because the free space is limited. Well, maybe your radio is bigger and you're lucky!
First I wired the charging board to the switch and the Bluetooth board. I used the original volume wheel as an ON/OFF switch, so on the wiring diagram the switch represents this wheel switch. You can easily figure out which leg is which. Some wheels or variable resistors has a bad habit and drop down the voltage. If you experienced that use an additional switch and skip the original one.
Then I connected the red LED to the switch and charger.
The charger module has 4 output terminals:
B+ : connect to battery positive terminal ( red wire )
B- : Connect to battery negative terminal ( black wire )
Out+ : Connect to Bluetooth board VCC through the wheel switch
Out - : Connect to Bluetooth board GND
Wiring the buttons: The order of the buttons of Bluetooth board is very important so please follow the wiring diagram!
The next step was the speaker and the microphone wiring. For the mic I drilled a small hole onto the front plane of the radio. I also covered it with hot glue because the glue isolate the mic from the speaker. In this way, we can avoid the annoying echo effect during phone calls.
Only in the last step I soldered the battery into the system and tested it. Please make sure that the wheel switch is in opened state before wiring the battery! Check again the whole wiring before test it! CHECK THE POLARITY!!!! CHECK IT AGAIN!!
Make a short test of Bluetooth connecting. Check the buttons and their functions.
So! The speaker is ready for reassembly!! And we hope the box can be closed easily.... :)
*The step-up module is optional. I didn't use it, but as you can see on the wiring diagram, the Bluetooth board can work with 6.5V as well. With this voltage level, the amplifier can run a 5W speaker. Preset the 6.5V with the screw BEFORE connect it to the amplifier! In this case, you will need a multimeter to set the correct voltage level.
Step 9: Put Everything Together
The reassembly is quite easy! I used the collected screws and washers to rebuild the radio! With the help of the Bluetooth technology and eBay, this radio has a second life!
Of course, it's not a 30W boombox and has limitations in sound quality. The Harman/Kardon speaker does his job so the sound is rich. The bass is unexpectedly strong thanks to the wood plate support and the hot glue sealing.
It has a 5-10 hours run-time depends on the volume level.
And.. well... I think this Bluetooth speaker looks pretty cool!
Step 10: How to Use It?
Prior to using the speaker for the first time, you must pair it with a Bluetooth-enabled device eg. your Smartphone, iPad, iPhone etc. The following steps describe pairing process for a typical Bluetooth-enabled device.
(a) Ensure the speaker is switched OFF.
(b) Place the speaker and your Smartphone not more than 1 meter apart.
(c) Switch on the speaker by turning the power wheel downward. The standby indicator will bright up in red and a long voice alert „bebep” can be heard.
(d) The radio is now ready for pairing.
(e) Activate your Smartphone's Bluetooth function, the Smartphone will search for accessible Bluetooth devices. (For details, please refer to the user guide of the Smartphone)
(f) Select "CSR8645” from the searching list and press “OK” to pair the radio.
(g) When pairing is completed, you will hear a short voice alert “beep”. Now the speaker is ready for use and in standby mode.
(h) You should now be able to use your radio to listen the music of your life. Please place your Bluetooth device within 10m of the radio. (Obstructions could cause shorter sensing distance.)
Good to know?
ON/OFF: Once you turned ON the speaker with the original power wheel the red LED bright up. You hear some "beep" sound which indicates that the speaker is ready to use. Turning the power wheel downward while the radio is operating the switch will turn the device off.
Volume: To adjust volume level press the buttons denoted located on the upside of the radio. The buttons now are hidden by the leather case. Always turn down the volume before using phone calls!
Play/Pause/PhoneCall/Re-pair: To play and pause music press once the button located on the upside of the radio. In the case of a phone call press once the play button to answer and one again to close the call. If you want to re-pair your device long press the play button until the voice signal.
Charge: To charge the radio use a micro USB cable and USB charger (AC100-240V, 50-60 Hz, Output: 5V 500 mA). A green LED indicates the charging state. Normal full charge time is around 2-3 hours. To keep the battery in good condition, charge the speaker at least once every 3 months.
Low battery indication: You will hear a voice alert of "beep" more times. It’s recommended to charge the speaker immediately to prolong the durability of battery and standby time. When the speaker has a low battery status, if the battery is not charged within a certain time, the speaker will switch itself off.
You are able to listen music with your iPhone, iPad, Smartphone or laptop. You can answer phone calls by pressing the PLAY button and use this radio as a speakerphone. There is no echo effect during the call.
Step 11: Do It Again!
If you saved something from waste, do it again! It's really fun to do, you may reduce the waste a little bit, and it'd be a perfect gift for friends, fathers, husbands or weddings, who knows.
I totally felt in love with this idea and I converted more radios into Bluetooth speakers. You can see some of them on the pictures I uploaded.
Thank you if you're interested and visit my Etsy shop.
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If you've made anything else similar, I'd love to see it! Post it in comments! :)