The market today offers a variety of speakers, including wireless. Cheap (for several hundred rubles) do not differ in special quality, since the electronics in them are the most short-lived, they often break down without working for several months. High-quality ones do not have sufficient power output, despite the service life of up to several years.
Tools and materials
A Bluetooth speaker can be made from any old parts. Round models, in which the speaker is facing up, are made from improvised materials. Any plastic pipe with an inner diameter of a few centimeters will serve as the walls of the case of a round standing model. Even a sewer pipe is used - the main thing is to install a speaker of a suitable size that will not fall to the bottom of such a design.
Another option is headphones for gamers who have served their time: they are often thrown away after 10 years, when the electrodynamic heads “sprinkle” in them.
A membrane cannot last forever - over the years, it cracks, and voice coils can burn out. But the headphone case is large enough to fit a “tweeter” broadband in the sound range, reproducing sounds from several hundred hertz to 20 kilohertz.
In addition to consumables on the body, bolts and / or screws are needed. In the case of bolts, Grover washers and nuts for them will be required. As glue - "superglue" such as "Second", drying out literally in a matter of seconds. “Moment-1” is also suitable - it is universal. To make the bottom, you need a couple of plugs. Both the pipe and the plugs are purchased at any building shop or supermarket selling building materials, electrics and plumbing.
The electronic component is a Bluetooth module, for example, the BLK-MD-SPK-B model. It costs on Aliexpress about $ 10. We need a connector and a plug in the standard 3.5 mm, multi-colored wires, a switch. The amplifier board for the selected speaker is assembled independently - on the basis of any of the microcircuits with an output power of 1 to 10 watts. In the electronic parts market, hundreds of models of ready-made sound power amplifiers are presented.
Of the tools you need: a drill, a flat and Phillips screwdriver, a low-power soldering iron for 20-40 watts. A more powerful soldering iron can overheat the thin and small conclusions of the radio elements. The fact is that any semiconductor radio components (diodes, transistors, microcircuits), when overheated, get a thermal breakdown and turn into a kind of piece of wire or a low-resistance resistor - it is absolutely useless in building active functional units and equipment units.
Soldering requires rosin, solder and solder flux. Insulation of individual live parts is performed by insulating tape, multi-layer coating with wear-resistant varnish, paraffin coating. The hinged joints of the wires also protect the insulating tubes - the outer sheath from thicker wires and cables, cut across, and not along.
A Bluetooth device differs from a regular speaker in the presence of an appropriate wireless module.
It takes up additional space, and its power requires a separate battery or external adapter.
In the latter case, the Bluetooth speaker loses the convenience of transportation - it will require additional power. The process of making a Bluetooth speaker with your own hands includes such moments.
- The manufacture of the housing according to the drawing, which will fit all the functional units . Cut the faces according to the drawing, drill and saw all the technological holes, gaps.
- Mounting the amplifier boards and the Bluetooth module, the battery and the USB charge board.
- Assembly of the finished parts of the device.
Having assembled the case, first install the battery.
Connecting a capacious battery
The battery capacity should ideally be up to several amp hours. The ideal option is to integrate 2-3 elements, the capacity of each of them reaches 2-3 A. It is possible to find batteries on smartphones or tablets in the radio market or in the service center, in which the controller has been calibrated and undercharges (or recharges) them. Batteries from such devices are often used as an internal power source for fully refurbished smartphones. Do the following.
- On the bottom (or the back, if the speaker is not round), try on how a single battery will be located - or a combined battery of several elements.
- Solder the power wires to it . Insulate them temporarily with insulation from a wire or cable of greater thickness - this will help to avoid a short circuit.
- Glue the battery to the bottom or back of the case with thermal or quick-drying adhesive.
The battery is ready to connect other devices. Next, follow these steps.
- Solder the wires to the USB charge module .
- Glue the module itself to the pre-prepared case, in which the hole for the plug-in USB plug is cut out. Hard glue is not advisable to use - it can crack multi-layer boards when cracked over time. Make sure that the socket is located opposite the rectangular hole - the USB plug will easily pass into it.
- Connect the output of the USB module to the battery input, observing the polarity.
To test the charge, turn on the battery for a few seconds or a minute. Use a USB port on your PC or “charge” from a smartphone.
A LED will light up on the USB module board, indicating that charging is in progress and that the module is connected correctly. The module microchip converts 4.8 ... 6 volts to 4.2 V, which is required for the battery, which will prevent the battery from discharging completely. To prevent the battery from being completely discharged during operation, you need a reverse module that converts 2.5 ... 4.2 V to 5 V, which is necessary for the Bluetooth module to work. Do the following.
- Solder the wires to the reverse module - a pair of wires to the input and output.
- Connect, observing polarity, the battery wires to the input wires of the reverse module . Leave a power gap for the switch - it is connected in series.
- Insert and insert the switch itself into the hot glue . For reliability, it is fixed from the ends with screws or self-tapping screws.
- Turn the switch on to the power supply by soldering its leads to the correct wires.
- Check that the reverse power module turns on and off - when the module is working on it, a separate LED should light up.
The result will be the appearance of a voltage of 5 V when the power is turned on from the switch. The module provides a load of up to 500 ... 600 milliamps without noticeable "subsidence" according to five volts. Next, follow these steps.
- Insulate all solder joints with adhesive sealant or electrical tape. Chinese modules with AliExpress, especially the cheapest ones, burn out at the slightest closure at the output - be careful, do not allow this.
- Place the reverse power module on the sealant.
The first part - the assembly of the power interface (power unit) is completed. Boards of functional units are securely fixed. It's time to install the amplifier and wireless module.
Soldering amplifier contacts
Select the location where the amplifier is installed. This is a much heavier radio card - due to the presence of a massive microcircuit and a large (almost with a fist) radiator. It needs to be fixed, unlike light, almost weightless power modules, more reliable - so that it does not move and does not fall on the rest of the electronics. Do the following.
- Position the amplifier board so that with one side (board) it lies on the bottom wall of the chassis. The second fulcrum (radiator) rests on another wall (for example, one of the sidewalls).
- Solder the wires to the input, output and power.
- Mount the mini-jack input connector (3.5 mm) - it will make the speaker more fully functional (AUX input). Solder three wires to it (“left”, “right” and “common”).
- Connect the wires of the connector to the stereo input of the amplifier, observing the marking.
- Supply power from the reverse module to the amplifier input.
However, you are unlikely to power a powerful (2 or more watts) amplifier from a 5-volt source. You will need a separate “petal” type power connector (or another) to supply voltage, for example, 12 volts.
Or it will be the installation of a separate module that turns 5 volts into 12-19. The last step is accompanied by significant losses in the power consumption of the microcontrollers - up to 40% of the efficiency is lost in terms of the watt-hours (or volt-amperes) consumed by the battery.
A powerful amplifier will turn a mobile (portable) wireless speaker into a stationary or mobile (for car). Mobility will be only partial: any gadget is connected via Bluetooth - but you cannot carry a column with you or carry a bicycle without a powerful PowerBank device for laptops or an additional battery. It is better to use it locally (at home, in the country, in the office or car). Follow these steps to connect a Bluetooth module.
- Decide where the wireless module will be located.
- Solder the wires to it - for power and output.
- If there is no strip antenna (separate track) on the module board, solder a piece of wire to the terminal marked for the antenna output.
Bluetooth radio operates at frequencies of about 2.4 gigahertz. The wavelength of this range is 12.5 cm. The “three quarters” pin is more effective than ¼ of the wavelength. ¾ the wavelength for Bluetooth communication is 94 mm, which will provide reliable coverage in a radius of 10-15 m. The sound output of the module is connected immediately to the input of the amplifier. It already includes a preamplifier that produces several units or tens of milliwatts, sufficient to "build up" the cascades of the main amplifier. Follow these steps.
- Connect the audio output of the Bluetooth module to the input of the main amplifier.
- Connect the power to the Bluetooth module from the reverse power board.
- Securely insulate all soldered joints.
- Glue the Bluetooth module to the desired location inside the speaker.
- If possible, position the antenna pin vertically.
Place the main board of the amplifier in a pre-prepared place and also stick it. Assemble the main body parts together with the mounted electronics. If the column is square, it is better to fix its walls on the outer corners, this will help in case of breakage to quickly disassemble it. Follow these steps to install and connect a speaker.
- Place the speaker in the pre-cut gap.
- If the speaker has "ears" - screw it to the edge of the body, in which direction it will be facing the listener.
- Solder the wires from the amplifier output to the speaker terminals.
- Close the column by setting the last, sixth face of it.
Assemble the speaker completely and start testing the sound.
Turn on the power from the switch. According to the block diagram, the amplifier and the Bluetooth module will work. If the amplifier is powered from a separate connector, connect, for example, to it an adapter from a laptop that produces 12 or 19 V (depending on what the variation in the supply voltage is for the amplifier board).
Bluetooth devices are automatically searched for on some modules. The device is available for detection from computers and gadgets. Select your module on your smartphone, tablet or laptop that appears in the list of detected ones - it is specifically signed. For example, the same BLK-MD-SPK-B card can give out the network name, for example, “BLK_MD” (or similar).
Connect to it from your device. Most often, a password of 0000 is required (if asked to enter).
Turn on any soundtrack on your gadget. The column should earn. Try the sound volume, sound quality. If the battery has "sat down", recharge it and repeat all the steps to test the speaker. Move away from it to the maximum distance until the sound of the audio stream from the gadget begins to interrupt - this checks its distance from which you can listen to music, play games or chat on the device.
Assembly begins at the stage of electrical work.
- It is more convenient to first connect the upper, lower and side faces.
- Then the installation and connection of the electronics and the battery is carried out.
- Next, the back wall is installed.
- After testing the electronics, the speaker is connected, the sound and overall performance of the device are checked.
- Finally, the speaker with the front wall is put in place, the column is finally closed.
After making sure that the column is working properly, decorate it with a special tape, synthetic wallpaper or fabric. It is recommended that you install a metal mesh or grille on the speaker side - it protects the diffuser from accidental poking movements.
Also keep in mind the following.
- Observe electrical safety when observing installation and test work. A voltage of more than 12 V will not allow wet hands to work.
- The assembled column is not used in cold weather, with high humidity and near a source of acid fumes. Otherwise, corrosion will “eat” the metal parts in a few years, and the column will fail.
- Connect the electronic modules correctly, reliably isolate all connections. Polarity reversal, overvoltage of supply voltage and short circuit of outputs instantly burn them. Do not use alternating current to power them.
Compliance with all recommendations will reward you with a self-made column that has been trouble-free for more than a dozen years.
On how to make a Bluetooth speaker with your own hands, see further.