40W Bluetooth audio, the speaker is equipped with two low-frequency speakers, passive membrane with Bluetooth 4.0 portable and powered by lithium battery. The shell is made entirely of plywood.
amplifier Yamaha 20W, Bluetooth 4.0 module, with battery charging indicator and 3 lithium-ion rechargeable batteries with ground insulator.
with protection circuit and fast charging 20W-low frequency speaker and passive film two two-channel frequency divider-protection board-charger
boost converter power connector and switch plywood 18 and 3mm thick block glue
The panel is cut from 3mm thick plywood using a laser cutting machine. The same tool makes all the necessary holes for speakers, switches, etc.
Processed front assembly panel
Polished front decorative panel
Use a pencil to draw the box plate according to the specifications
img8 board with electric drill processing
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Tools used in DIY work
Box plate with holes processed
Curve saw processing wood board
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Assembly effect drawing
Wooden frame processing, assembly, glueing and fixing
Alignment and placement
img_p17 After pressing the wooden box with cement brick
img_p17 The box body
is sanded with sandpaper
After the outer panel is cut out,The author continued to glue them into several layers to achieve a thickness of 18 mm. This will provide strength for the case.
Step 3: Prepare the backplane
The passive film is glued to the assembled backplane, which increases the range of the speaker to respond to the pressure difference inside the device. It is very important to seal the enclosure at the end of the work.
Next, the author starts to create a circuit for device operation. The picture above is the assembly diagram of the column circuit.
Step 5: Working battery pack The author uses a fairly cheap Samsung pink 18650 battery. In order to protect them, a board is installed to prevent overcharge, overdischarge, short circuit protection, etc. The use of lithium-ion battery protection board is very important. It is also important to pay special attention to the choice of charging equipment.
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0 pimg 31 before creating the same battery voltage. This is important because different battery charging in the circuit can confuse the protection board and may cause premature battery failure. In order to connect the battery into a battery, a purchased case is used, and they will be placed in a compact location. In this case, the wire connecting the battery is soldered to a thicker wire to improve the reliability of the device.Then solder the protective board and the switch with the power connector to this shell. Pay special attention to the power connector: the bent contact on the right side can be completely removed, the left side can be grounded, and the middle one is positive. To ensure that the polarity of all contacts is correct, I suggest walking with a multimeter and checking the voltage. After making sure everything is done correctly, you can start soldering the connector into the protection circuit. Then you should check the performance of the entire power supply circuit. Then use tape to fix the wires to the housing. Then the author welded the voltage converter. This device requires a voltage of 14 V, so use a screwdriver and a multimeter to adjust the converter accordingly by tightening the copper screws on the board.
Step 7: Connect the Bluetooth module and amplifier
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_p0 img 36 I decided to stick the Bluetooth module directly on the power amplifier board. It is important to leave enough space between the amplifier and the module chips, as these chips will get hot and require air circulation. In addition, when they are in contact, a short circuit may occur. The power amplifier board and the module are glued with hot glue, so that there is enough distance between the chips on the board. It should be understood that when using a 5W Bluetooth module, the ground isolator must be connected to the power cord of the module, otherwise it will cause interference and affect the sound quality.
Then connect the module output contacts to the amplifier input contacts. Then connect the power supply pin of the amplifier to the output pin of the converter. Therefore, the amplifier will be powered by 14 V. The Bluetooth module will receive an input voltage of 10 to 12 V, depending on the battery voltage, because it is connected to the input pin of the boost module. All of these can be seen in the attached photos.
Step 8: Connect the divider
The divider should distribute the audio signal to the high and low frequencies and route them to the appropriate speakers.
After desoldering, hot glue should be filled to ensure fixation. By the way, applying hot glue to the corners of the case from the inside also helps in the necessary sealing of the case. Gluing the side panels
After assembling the components, the bonding side panels are coated with wood glue along the edge of the panel and pressed tightly. When the panel is dry, the internal joints and other parts must be sealed with hot glue.
This will not only improve the sound quality produced by the speaker, but also provide additional power to the entire cabinet.
In order to make the front panel rigid, additional MDF battens are also glued.
Then glue the tweeters and connect the wires of the crossover to them. The panels are also installed on glue and seal the seams.
After assembling and drying the speaker box, connect the subwoofer to the front panel.
First, connect all necessary wires to the speakers, and then fix them on the front panel with screws. After
, the device can actually be used. After testing and verifying that all speakers are working properly, the electronic service port cover is also closed. After
, the main body of the product can be painted to give it a store-bought appearance
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