In this tutorial, I will show you how to make a fixed bookshelf Bluetooth speaker.
It is fixed because it does not intend to move, which is why it is not battery powered but power supply. It has a 100W amplifier and a 5.0 Bluetooth audio module, which are placed in a wooden box. In order to make a box, I use beech wood and fir-tree, I have some fir-tree waste, in addition, I bought a beech wood. I use these two because I think they will be better compared to each other. I will also share some tips and techniques on how to check everything is working properly. If you decide yourself try this project, please troubleshoot.
Supplies
Bluetooth audio module
Power 2X
Amplifier (here I use TPA3116 D mono amplifier)
speaker
Speaker grille (optional)
high-pitched speaker
100Ω resistor 2X
board
L-type wooden strip
Cable connector
screw
nail
metallic line
change
Capacitors and coils (or cross)
power cable
Tools: Solders and Some solders, drill bits, thermal glue guns, puzzles (or hand saw), belt machine (or file), screwdriver, pliers, mare knife.
Step 1: Get your components
Although I wrote a list of materials, the speaker is converted to the restriction of the electric energy of audio, which means you need to make sure that the speaker you use can handle the energy generated by the amplifier.
Therefore, for example, I use the TPA3116 D mono amplifier, which is 100W on the 2Ω load, because I used a 4Ω speaker, so I got the maximum 50W output power.
Step 2: Making a speaker hole
In this step, two holes are made, one for speakers, one for treble speakers.
First, measure the speakers and treble speakers you are using, and depict the contours on the board, then drill a hole to insert the puzzle blade, then cut out your previously depicted circles. This operation is repeated for high-wave speakers.
Step 3: Measure the box 1/3
First cut off the front (the one of the speakers above), then the back of the box, because the two are the same size of the first side (cutting from the wooden board), the size of the size is the back, then cut the side .
I have not shown any size here because they are not important, they may vary.
Step 4: Measure the box 2/3
In this step, the top and bottom are made (at this time I changed the wood I used, just to make them comparison each other). First, measure the length of the side of the side created in the previous step, depicted it, and then cut it off.
This operation is repeated on the top.
Step 5: Measure the box 3/3
At this point, you should have four edges of the box, assemble them in this step, so you can draw two other side, then cut them.
Step 6: Place the box together
In this step, put the box together, but let the side open so that you can install electronic devices in the box.
Drill the guiding hole and place the box with a screw.
Step 7: Troubleshooting (Electronics)
To make it working properly, you need to power the amplifier and Bluetooth module, but the problem is that you should not use the same power supply to power it, and the ground circuit is a reason. The ground circuit is caused by the interconnection of the electrical equipment, causing multiple ground paths, although you can use one of the ground loop isolators to solve this problem, but I haven't do this here. In order to solve this problem, I used two power supplies. A computer charger (for amplifier) from the old laptop, another from the Bluetooth module (5V).
Please note that if you use a power supply with a ground loop isolator, you should also use a certain pressure-on converter to power the Bluetooth module.
Step 8: Prepare for power and electronic equipment
You can remove these power supplies to expose the internal wires, or you can use the cables such as cable connector to connect proper circuit connections.
If you use a prefabricated amplifier, you should be able to see some letters on it, they will tell you where something is placed. VCC represents the power input OUT represents the output (which is the speaker to go) + GND - (or something like IN) represents input (from Bluetooth signal here). On the Bluetooth module, you should also see some letters, more accurately, R, GND, and L. This is a stereo output because it is a mono amplifier that you need to mix them into mono. Just use two 100 ohm resistors. A resistance is connected to R, then the other is connected to L and twisted the end of the two resistors. And weld a small wire to GND (this is the output of the Bluetooth module).
Step 9: Electronic products assembly
Ok, this is the way to connect the output of the Bluetooth module to the amplifier input. The output of the speaker and the treble trumpet, the last power supply, a connected power, one picks the blue tooth module.
Of course, to power the entire situation, make sure to drill the power cord. And it is also hot to bond all components to secure them in place.
Step 10: Cross
For best results, you need some experiments.
Therefore, the purpose of the divider is to eliminate some frequencies that enter the treble speaker. Simple divider is a combination of capacitors and inductors. As far as I said, I used two parallel 10 UF capacitors (equivalent to a 20 UF capacitor) and also used a hand winding. Capacitors and coils are connected in series, which means that one wire output from the amplifier is connected to a line of the treble speaker, and the other wire output of the amplifier is connected to a wire of the coil, then connects from the coil to the capacitor and then slave the capacitor Go to the high-wave speaker. All in all, the output of the amplifier enters the speaker and then divided into the treble speaker.
Step 11: Complete the box
After the electronic equipment is in place, close the last side of the box.
Step 12: L-type wooden strips
This L-shaped wooden strip has a 90-degree bend, which is very suitable for the edge of the box. First measure the measured side, then cut these debris. After that, use some nails to fix these parts in place, that is, this is the case.
Step 13: Switch
Finally, add a switch to this, you should cut out the entire power cord or only cut a wire, in my case, I cut a wire with a shear clamp. With a switch, this project is completed.
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