APPLICATION OF MICROCONTROLLERS IN REALIZATION OF THE CALCULATOR OF CONTINUOUS WAVELET TRANSFORMATION INTENDED FOR WORK IN CONDITIONS OF ARCTIC
The paper is devoted to the development of a continuous wavelet transform computer, designed for operation in cold temperatures (up to -60oC). MSP430G2553, ATmega328P and STM32F401RET6 microcontrollers are considered as an element base for the implementation of the calculator. The results of continuous wavelet transformation calculation were obtained using microcontrollers, taking into account their clock frequencies and limited internal memory. The dependence of the continuous wavelet transformation calculation speed on microcontrollers at different signal lengths and with different ways of using wavelet in the algorithm is obtained and analyzed: when it is loaded from the internal memory of the microcontroller and when it is calculated directly on the microcontroller. In all the experiments, fragments of an electroencephalogram with a sampling rate of 250 Hz are used as analyzed signals. The device description and functional schemes of the continuous wavelet transform calculator, developed for various types of tests are given: for estimation of the speed of calculation of continuous wavelet transformation and for testing of the device at low temperatures. The results of the test of the calculator in the climate chamber are evaluated. As a result of the research, it is shown that among the devices considered, the STM32F401RET6 microcontroller is best suited for calculating continuous wavelet transformation. It took 0.57 seconds to process a 1 second (250 counts) fragment of the electroencephalogram when used. At the same time, the information content of the wavelet spectrogram was preserved. It took 2516.84 seconds to process a strip of 4500 counts with the wavelet calculation directly on the microcontroller. Studies in the climate chamber have shown that the developed device with an installed battery capacity of 20 A·h worked at a temperature below -40 o C for 129 minutes, of which 101 minutes at a temperature of -60 o C. This time is sufficient for electrocardiological or electroencephalographic examination of 5 people