Bluetooth Embedded Portable Oscilloscope

Abstract

Portable oscilloscopes currently in the market are very expensive, less power efficient and have small low resolution displays. This paper presents the design and implementation of a low cost, portable, lightweight; low power, dual-channel oscilloscope, consisting of a hardware device and a software application. The device is equipped with a Bluetooth module to provide connectivity to a device with Bluetooth, running the Android operating system (OS), in order to display the waveforms. Android OS is selected because there are a decent number of Android device users and most of these devices satisfy the requirements of the oscilloscope’s software application. The hardware device includes circuitry to capture the input voltage signals and an embedded Bluetooth module for transmitting the captured signal information to an Android device for displaying the waveform. The Software application developed for Android receives the data transmitted from the hardware device and plots the waveform according to the display settings configured by the user. These display configurations are transmitted to the hardware device once they are set by the user, and are used by the hardware device to set the sampling rate and the values of samples. For optimal use of the available bandwidth, the application provides two modes of operation, namely single channel mode where only channel 1 is operational and dual channel mode where both channels 1 and 2 are operational. The user can select a mode from the application, which in turn sends a message to the microcontroller which then changes the sampling frequency accordingly: a higher sampling rate for single channel and half of that for dual channel.