Design and Construction of Wireless Speaker Using Bluetooth
M. Amewornu Erstina · 2016
This paper focuses on design and construction of 2.4 GHz wireless system, to transmit stereo audio from a 3.5 mm jack to play on a speaker. The transmitter will convert the audio from analog to digital with an Analog-to-Digital Converter (ADC) and transmit this digital data via a 2.4 GHz transmitter. The aim of the project is to design a system that will receive wireless stereo audio from a source and give an output useful for both indoor and outdoor purposes. The objectives of the project are to design and construct a low power transmitter so that it can be powered with 9V battery or PSU and be small and portable and to produce enough power to speakers to have “loud” music while limiting noise and distortion. The stereo amplifier used in this design is the MAX98400A Class D amplifier. An available class AB linear amplifier is an option for this project, but the higher-efficiency Class D amplifier consumes less power and dissipates much less heat. This amplifier exhibits a high 107-dB signal-to-noise ratio (SNR). This design uses a Nokia BH-214 Bluetooth stereo headset. It has the 3.5-mm audio connector, making it very easy to take audio signals from a headset’s printed-circuit board (PCB) and feed signals to the stereo audio amplifier.