Abstract – This article presents a report on the Procedure, Function, Science, Components required and Precaution to be taken for making a bluetooth speaker. A Bluetooth speaker is a wireless sound amplifier that is connected to another source with bluetooth technology. It needs a speaker, amplifier board, bluetooth module, switch and battery. The method shown in this article can be used to make a simple bluetooth speaker which can be modulated to one’s preferences. Keywords – Doping, Amplification, Transistor

Introduction

A bluetooth speaker is an audio system that uses bluetooth technology to connect with another device and play audio from the connected device. Bluetooth communication is a wireless technology and does not require wires to connect and transmit signals. The bluetooth speaker also uses an amplifier to amplify the input sound output through the speakers.

Components

• Amplifier Board (PAM8403)
• A Bluetooth module
• Switch
• 18650 Li-ion battery
• Two 4 Ohm 3 Watt speakers
• Connecting wires

An amplifier board (PAM 8403), a bluetooth module, switch and a battery are used to make a bluetooth speaker. The speaker is connected to another device using bluetooth technology by the bluetooth module. Short range radio frequency is depended on  Bluetooth. A bluetooth speaker can have any device connected to it using radio waves, as long as the required distance is maintained. Audio data is received by the bluetooth module. The amplifier board, composed of many transistors, amplifies the sound. The speakers receive the amplified audio which is sent out. A lithium ion battery is the power source used. The battery and the amplifier board are linked by the switch. The amplifier board is also linked to the bluetooth module and the speakers. For charging the battery, a charging module is linked to it.

Scientific Theory

P-type doping is used in the center of the silicon wafer, and N-type doping in the sides. Two power sources are connected. The electrons are flown to the P-type part. Some of the electrons get attracted to the first power source. The P-type is made narrow, so most of the electrons continue to flow and get attracted to the second power source. This is called a bipolar junction transistor. A small base current is amplified to a higher collector current. This is how amplification works. A transistor amplifies small signals.

Procedure

A box for the speakers with two holes for the speaker heads was made using wood. Dimensions were drawn on the wood and cut accordingly. The wood pieces were stuck and made into a box. Soldering of the components in the circuit was done in the following manner: The speaker heads were stuck around the holes and the rest of the components in the box. An opening for the switch and the charging port at the back of the speaker  was made.

Precaution

• Ensure the speaker is not used while the battery is charging.

Outputs

The bluetooth speaker can be connected to another device, for example, a phone. The audio signal is received and amplified by the speaker and sent out. The sound is clearer and louder through the speaker.

Conclusion

The speaker was a project made during the work and study. It was made to fulfill the requirements of the environment. It was observed that a handmade speaker was not only more economical than a ready-made one but also gave a good output.