Build Your Own DIY Bluetooth Speaker

Are you tired of being tethered to your phone or computer when you want to listen to music? Do you wish you could dance to your favourite songs without worrying about tripping over a cord? If so, then you are in luck! In this tutorial blog, we will show you how to build your Bluetooth speaker.

Bluetooth speaker kits are a great way to enjoy your music wirelessly. They are also a relatively easy project to build, even if you are not very experienced with electronics. In this tutorial, we will walk you through the steps of building a Bluetooth speaker from start to finish. We will cover everything from choosing the right components to assembling the kit.

Components Required

• 1 x 3.7 V Li-ion Battery
• 1 x Bluetooth Speaker Kit
• Connecting Wires

Circuit Diagram

Connections:

• Connect the +ve terminal of the battery to the B+ pin of the module.
• Connect -ve terminal of the battery to the B- pin of the module.
• The speaker connections do not require any +ve/-ve pins, since the module uses a mono audio function. Insert the connectors in the Speaker Connector section and solder the wires to the speaker.
• All the necessary connections are now completed.

Once you are done making the connections, the overall circuit will look like this:

Bluetooth Audio Amplifier Board

The exceptional versatility of this Bluetooth module is what distinguishes it. It provides a variety of input ports, such as Bluetooth connectivity, aux-in, and even SD card slots, which guarantee compatibility with different audio sources. Whether you desire to wirelessly stream music from your smartphone, connect a laptop using an auxiliary cable, or play your favourite tracks directly from an SD card, this module caters to all your needs.

Let us take a look at all the important pins present in this module:

• Power Button: The purpose of this button is to activate or deactivate the module.
• Multi-Function Button: The module provides a means to alternate between its various modes, a topic that will be further explored in subsequent sections. Additionally, the volume of the speaker can be adjusted using this. You can also switch to the next track or the previous track using this button.
• Battery Connector: The module derives its power from a battery, and its connection is facilitated by these connectors. A Li-ion Battery with a voltage of 3.7V is capable of powering the device. The highest voltage it can reach is 5V. By connecting your mobile device to the battery using Bluetooth, you can view its current status. At a voltage of 4.2V, the battery level will display as 100%, while at 3V it will show as 0%.

• Speaker Connector: The speaker connectors are utilized for linking the Bluetooth module to the speaker.
• Micro USB: This is the method utilized for charging the batteries that are connected to the Bluetooth module.
• JL AC22BP: Using JL AC ICs in Bluetooth Speaker Kits greatly enhances audio performance. These ICs possess advanced DSP capabilities, minimal noise and distortion, versatility, and effortless connectivity options, all of which contribute to creating an immersive and captivating audio experience. Whether you are an enthusiastic audiophile or enjoy DIY projects, integrating JL AC ICs guarantees outstanding sound quality that enhances your enjoyment of music.

• AXS 2030: With its advanced digital signal processing (DSP) algorithms, this IC is capable of accurately controlling and manipulating audio signals. It offers a range of functions including equalization, crossover implementation, and dynamic range control, guaranteeing optimal audio performance and customization options.
• Input Pins: There are three input pins available for connecting the module to an external source and playing music. These pins include the AUX pin, USB A pin, and an SD Card slot. The functions of each mode will be discussed later.
• MIC Input: A microphone input is present on the module to pair it with a microphone. Using this you can talk on calls if your mobile is connected to this module via Bluetooth or AUX.
• FM Antenna: When you attach an FM antenna to the slot of your Bluetooth Speaker Kit, it improves your ability to receive FM radio signals with better clarity and stronger reception. This enables you to access a wider variety of local and live content, expanding the options for what you can listen to and keeping you connected to the latest news, music, and events in your vicinity.
• External LED Slot: This can be used to connect and power an external LED with this module. However, it is not of much use.

Working of Bluetooth Module

Now that we are done with understanding the pins of the Bluetooth module, let’s explore the working of its different modes.

The Bluetooth module provides 5 distinct modes for connecting and streaming music, which include Bluetooth Mode, AUX Mode, FM Mode, Pen Drive Mode, and SD-Card Mode. Let’s discuss each mode individually, but first, let us understand the working and importance of the Multi-Function Button.

The Multi-Function Button present in the module is multi-functional and offers many control features like switching between modes, controlling volume, and changing tracks. Let’s see how to properly use the control switch.

• Switching Between Modes: When you turn on the device, it automatically enters Bluetooth Mode. You have the option to change the mode by pressing and holding the Control Switch. The succeeding mode is FM Mode and it is then followed by AUX Mode.
• Controlling Volume: The volume of the speakers can be easily controlled by sliding and holding the switch in either the right or left direction. If the switch is pushed towards the right and held, the volume increases. Conversely, pushing and holding the switch in the left direction will decrease the volume.
• Controlling and Switching Between Tracks: By pressing the Multi-Function Button once, you can pause or play the song. If you want to move to the next track, just flick the switch to the right. If you want to go back to the previous track or restart the current track, flick the switch to the left.

Okay so now we know how to switch between the modes, but how do these modes work? Let’s check it out.

• Bluetooth Mode: When the device is powered on, it enters Bluetooth mode by default and can be paired with nearby devices. The onboard LED flashes until a device is connected. After a successful connection, the LED ceases flashing and remains continuously lit. To connect your device to the Bluetooth module, simply activate the Bluetooth feature on your device. Afterwards, access the Bluetooth settings where you will find a device labelled 009.9M, which corresponds to our Bluetooth module. Proceed to pair with this device, which may take a few seconds, and then you can enjoy playing music. The LED will begin flashing again after the user has played a song, indicating that a song is currently being played.
• FM Mode: As explained above, when you hold and press the multi-function button towards the centre, the mode will change to FM. The scanning for channels will commence in the Module, and this can be verified by observing the LED flashing. Once the scanning is completed and a channel is being played, the LED will blink at a slower rate.
• USB/ SD Card Mode: The module will switch to USB/SD Card Mode automatically upon inserting a USB drive or an SD Card. The LED will remain lit continuously in the absence of any songs to play or in the case of a paused song. When a song is played, the LED will flash. The songs on the USB/SD Card must be in MP3 format to be played by the module.
• AUX Mode: As previously explained, if you press the multi-function button twice and hold it towards the centre, the mode will switch to AUX. The audio input can be obtained by linking the module to a mobile device using an AUX Cable. The LED will consistently flash, regardless of whether the song is being played or paused.

Charging of Batteries

The Module is equipped with a Micro-USB input port used for charging the Battery pack it is connected to. Additionally, a Red Led is present to signify the charging state of the module. The Red Led remains constantly lit during battery charging.

The charging voltage at the battery terminal is around 4 volts, which is the required voltage to charge the Li-ion Batteries. The charging current is around 200mA.

Speaker Specifications

The Bluetooth Speaker kit includes both a speaker and a Bluetooth Module. The speaker has a rating of 4Ω and 3W. To connect the module to the speaker, you can solder the connector cable to the speaker. To ensure proper connection, refer to the connection diagram. The kit also comes with a connector cable for user convenience.

Conclusion

To summarize, Bluetooth Speaker Kits provide an engaging audio experience that combines the convenience of wireless connectivity with exceptional sound quality. Due to their small size, appealing design, and adaptable features, these kits have gained popularity among individuals passionate about audio and those who enjoy do-it-yourself projects.