Bluetooth Low Energy Applications in MATLAB

This chapter presents Bluetooth Low Energy (BLE) applications in MATLAB. Through these applications we acquire measurement data from BLE compatible sensors to PC. The sensors are CC2541 Keyfob and CC2650 Sensor Tag. The first one contains an accelerometer and a temperature sensor while the second one contains more sensors, but inertial sensors and magnetometer are invoked. The PC should be equipped with a general USB BLE adapter. The most important steps for implementing a BLE application are presented: scanning, connecting, configuring and data reading. Following this, more detailed applications are presented: a wireless sensor network for temperature measurement with three Keyfob-based nodes, an application that displays in real time accelerometer data and a heading computed method using either the gyroscope or the magnetometer of CC2650 Sensor Tag. The most important MATLAB elements that are used to implement these applications are different types of variables such as structure, table and object, methods to implement endless loops and real-time display of acquired data and using quaternions to handle 3D orientation of a device

Extending the frequency measurement of a single sinusoid above the Nyquist limit based on zero crossings method

This paper presents the measurement of the frequency of a single sinusoid by counting the zero crossings and extends it above the Nyquist limit. For this purpose, two sets of samples are acquired, at two different but close sampling frequencies. Based on the count of zero crossings obtained in each case and on the two sampling frequencies, four coefficients are computed. Then, the most appropriate coefficient from those four is used for calculating the frequency. The less the difference between the two sampling frequencies, the higher the maximum measurable frequency. The relative error is of the order of 10-4, and the measurement time is about 100 ms. The method was experimentally tested using a National Instruments PCI 6023 data acquisition board.</jats:p