Embedded instrumentation for skin admittance measurement

Skin admittance measurements are used in several biomedical applications, and the technology available today opens for new design solutions. The digital instrumentation has several advantages to the conventional analog instrumentation by needing fewer components, having lower cost, better reliability and is easier to modify in the field. A design alternative is presented which uses an 8-bit microcontroller and few extra components for skin admittance instrumentation. Most of the measuring tasks are handled digitally in software by using a point-by-point routine allowing continuous conductance and susceptance measurements with low processor usage. The design is best suited for low-frequency measurement instrumentation where small size and low cost of the instrument is required.