Implementation of Signal Acquisition System (SAS) for Large Voltage Waveform Using Low-cost Raspberry Pi Pico

In response to Industry 4.0, smart manufacturing with highly developed performances has become an interest of research topic being intensively discussed. To achieve smart manufacturing, it is required to develop an intelligent factory having smart machines. Therefore, advanced low-cost sensing technologies are essential for gathering data and utilizing it for effectively building a smart machine. Recently, various high performance microcontrollers capable of performing data acquisition have been developed for the application of internet of things (IoT). However, the data acquisitions of those microcon-trollers are limited to several volts only. Therefore, voltage attenuation is required, thus resulting in the problem of reducing the resolution of acquired signal. In this paper, a signal acquisition system (SAS) using the Raspberry Pi Pico (Pico) that can acquire a large voltage waveform is proposed. Based on the operation of amplitude division, a complete waveform can be reconstructed via the proposed SAS without reducing the resolution. The SAS consists of three components: a signal acquisition circuit dividing a large voltage waveform into several segmented waveforms, a Pico reconstructing the piecewise segmented waveforms, and a laptop recording and displaying the acquired waveform. Through simulation works and practical experiments, it has been demon-strated that a sinusoidal waveform with the amplitude of 10 V and driving frequency of 100 Hz could be well reconstructed. Compared with the method using an attenuated waveform, the amplitude division featured much smaller acquisition error. Future works are to reduce the error of the acquired waveform by compensating for the non-linearity of the circuit and to implement a real-time acquisition system.