Circuit Lake

Electronic Project and Circuit Collection

AVR based EKG Monitoring

12/11/2009 Category: AVR, Monitoring, Project

This EKG monitoring instrument uses the microcontroller AVR AtMega103 microcontroller to control and store the data acquired via EKG monitoring systems involved. The aim of this project is to accurately measure the electrical activity of heart with EKG monitoring instrument. This is achieved by building an instrumentation amplifier which is specifically designed for bio-electrical signal measurement.

AVR EKG monitoring

In addition, two active filters – one high pass and one low pass – were employed to eliminate measurement errors. The high pass filter was used to remove any dc drift with cut-off frequency of 0.2Hz, while the low pass filter was used to eliminate anti-aliasing effects.

User input from the PinD0 initiates the data acquisition process. Once initiated, the signal acquired via EKG monitoring instrument goes through the Analog to Digital Converter of the microcontroller at sampling frequency of 720Hz and this data is stored in external SRAM. Upon completion of data acquisition process, the user can initiate transmission of the stored data via the Hyperterminal to be interfaced with Matlab. Data can be further analyzed with Matlab software for future studies, such as RR interval analysis, QT interval analysis.

© Jeff S. Lee and Young Ho Cho

EKG Monitoring
Project Documentation and Schematic