Mini Bluetooth Speaker
This tutorial is about the building of a 3 in 1 Mini Bluetooth speaker. Making Bluetooth Speaker is great as the first project for anyone that is just starting with making. It’s relatively simple to build and is useful. Everything in this project can be built using common hand tools. So anyone who has some basic tools can build it during the weekend.
This Speaker Can be used as:
1. Bluetooth Speaker
2. Power Bank
3. Flashlight
You may checkout my project DIY Mini UPS for WiFi Router V2.0
Supplies:
1. 3W Speaker: Amazon / Banggood
2. Passive Radiator: Amazon / Aliexpress
3. Bals Wood – 12 x 7 cm , 12×4 cm, 4×6 cm : Amazon / Aliexpress
4. Bluetooth amplifier module: Amazon / Banggood
6. 18650 Battery: Amazon / Banggood
7. 1W LED: Amazon / Aliexpress
8. LED Lens: Amazon / Banggood
11. 330R Resistors: Amazon / Banggood
12. 3R 0.5W Resistor: Amazon / Aliexpress
13. Slide Switch: Amazon / Banggood
14. Rocker Switch: Amazon / Banggood
15. 22 AWG Wire: Amazon / Banggood
16. Super Glue: Amazon / Banggood
Enclosure
I made the enclosure for Mini Bluetooth Speaker by using 4mm balsa wood. The complete enclosure has 6 parts :
1. Front & Back Panels (12 x 7 cm )
2. Top & Bottom Panels ( 4 x 12 cm)
3. Left & Panels ( 4 x 6 cm)
It is not mandatory to use balsa wood, you can use plywood/pinewood / MDF also.
Making the Front Panel
In the front panel, I have installed two speaker drivers. So, first I measured the speaker driver by using my vernier caliper. The diameter is 40mm.
I have drawn two circles with a diameter equals 36 mm and the center to center distance between them is 50 mm.
Then I cut out the marked portion by using a Xacto knife. At last, you can smoothen the edges with the help of sandpaper.
Making the Back Panel
In the back panel, I am going to install the passive radiator. I traced out the outline of the passive radiator. After that, I have drawn an offset line 3mm inward.
Then I cut out the marked portion by using the Xacto knife. Smooth the edges with the help of sandpaper.
Installing the Speakers and Passive Radiator
Use super glue to mount the drivers. I will recommend Superglue gel, as it takes some time to dry out. So that you can align the driver along with the slots.
After mounting the drivers, seal them by using hot glue. Repeat the same process for mounting the Passive radiator.
Preparing the Side Panels
To prepare the side panels of the Mini Bluetooth Speaker, I took the outline measurements and cut them out by using the Xacto knife.
In the left side panel, the following components are installed:
1. Two LEDs for TP4056 charging status
2. One LED for Power status
3. Slide Switch for Power On / Off
4. TP4056
In the right-side panel, the following components are installed:
1. LED Lens ( Flashlight )
2. Switch for Flashlight
3. USB Socket ( Powerbank )
Note: I have used two 5mm LEDs for TP4056 charge status indication, I will recommend using 3mm.
Schematic Diagram
The schematic diagram for Mini Bluetooth Speaker is pretty simple. The heart of the circuit is the TP4056 board. It charges the 18650 battery and disconnects the load when the battery voltage drops below the threshold limit.
The output terminal of the TP4056 is connected to the following:
1. Bluetooth Amplifier Module
2. Flash Light
3. USB Boost Converter
4. Power status LED
The red lines are positive and the black lines are negative.
Battery Connection
The difficult part is soldering wires to the 18650 li-ion battery. First, clean the terminal surface, apply flux on it. Then solder a red wire to the positive terminal and black wire to the negative terminal. Solder the wires as quickly as possible because excess heat from the soldering iron tip may damage the battery.
To avoid any accidental short circuit, I insulated the two terminals by using masking tape.
I used a TP4056 li-ion battery charging module to charge the battery. There are two different types of modules available in the market. One is Without a battery protection chip and another With a protection chip. I will highly recommend using the module which has a protection chip and micro USB port.
Soldering Charging Status LEDs
The TP4056 module has inbuilt two status led to indicate the charge status. In this case, after installing the TP4056 the LEDs are away from the panel. So we have to mount two external LEDs.
The onboard LEDs are soldered after the 1K current limiting resistor.
I solder 3 wires as below
1. Green wire to the TP4056 pin – 6 ( before the resistor ) – Green LED Cathode
2. Red wire to the TP4056 pin – 6 ( before the resistor ) – Red LED Cathode
3. Black wire to the TP4056 pin – 8 – Common Anode
I joined the two LEDs anode together and soldered them. After that, I soldered two 330 Ohm resistors to the LED cathode.
Power Bank Circuit
The maximum voltage we can get from the 18650 is 4.2 Volt when it fully charged. But all USB device runs 5V and above. So we have to raise the battery voltage to above 5V. This can be achieved by using a boost converter. I preferred to use a boost converter along with USB Socket.
The connection is very straightforward, with just two wires to the input terminals. Then connect them to TP4056 Output terminals.
Be sure the polarities are correct. You can always refer to the schematic diagram shown in the earlier step.
Flashlight Circuit
To make the flashlight, I have chosen a 1W power LED. To run the power LED efficiently, you will require a dedicated LED driver. But to make the circuit simple, I have used a current limiting resistor ( 3R, 0.5 W ). The exact value of the resistor can be calculated by using this calculator.
The LED that I have used comes with a heat sink. Never forget to use a heatsink with a power LED.
To make the flashlight, I used a LED lens as shown in the above picture.
Installing the Side Panel Components
After making all the circuits, I mount the components to their respective slots.
Then I seal all around by applying a sufficient amount of hot glue.
Then complete the circuit as per the schematic diagram.
Making the Speaker Circuit
The speaker terminals are marked with polarity. I soldered the speaker terminal wires that come with the Bluetooth amplifier module. The blue wire is positive and the yellow wire is negative.
Then connect the wires to the Bluetooth Amplifier module as shown in the schematic diagram.
Gluing in the Panels
I started the final assembly by placing the front speaker panel at the bottom as shown above. Then glued all the sides and at last the top panel.
I used superglue gel to mount the panels. I seal the edges by using hot glue.
I applied wood glue on the outside joints and leave them to dry for a couple of hours. After drying, I sand out the edges to give a perfectly smooth surface.
Final Testing
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After building your Mini Bluetooth Speaker, I will recommend charging the battery with a USB charger. During the charging, the status LED glows red and when it becomes blue indicates that fully charged. Turn on the power switch, the green led on the left panel will ON. Turn on Bluetooth on your smartphone and search for nearby Bluetooth devices. The name of this device is ” DW-CT14+”.Then pair it and play your favorite song.
Enjoy !!!
