DESIGN AND DEVELOPMENT OF A PORTABLE DATALOGGER FOR BIOMEDICAL SIGNALS (USING ELECTROCARDIOGRAM SIGNAL AS TRAINER

Abstract

The need for lower cost of medical equipment and reduction in the delay of delivering health services to patients within and outside hospital environment is on the increase in developing countries. This research work focuses on the design of a portable and low cost data logger targeted for various biomedical signals, using ECG signals as trainer. The data logging system was designed and developed for acquiring and storing ECG of a patient and the performance of the system was evaluated. The data logger has two major sections; Signal conditioning and Storage Sections. The Signal conditioning section of the system was designed and simulated in the Multisim simulation environment which involves the instrumentation amplifier, the Filtering circuit, the Second Amplification and the DC offset circuits. The Storage section of the system was designed and simulated in Isis Proteus. PIC 18F4620 microcontroller was programmed in C language using MPLAB C18 compiler to perform Analog to Digital Conversion and communicate with the micro secure digital (SD) card (popularly referred to as memory card) where the samples of the signal are stored. The microcontroller program also included interactions with Pushbuttons and a Liquid Crystal Display (LCD) for operations and control. The performance of the circuit was evaluated by comparing the input analog signals with waveform plotted from samples stored in the memory card. It was seen that most of the information contained in the original signal can be retrieved from the stored signal. The stored digital samples can be transferred to a Computer system using a SD card reader or played back for transmission over wireless medium.