Microcontroller-based sensor to measure serum column height

摘要

A novel microcontroller-based sensor system has been designed developed. and validated to find the column height of serum extracted from human blood samples in clinical tubes. The sensor system, based on capacitive principle, can distinguish thechange in capacitance due to a change in dielectric properties as a tube held on a linear carriage is passed through the sensor's probe. Hardware and software were developed for implementing the motion control, data acquisition, transition pointalgorithm, and communication. The system can measure column heights as long as 76 mm while displaying a final resolution of 1 mm and an accuracy of±1 mm full scale. The system is also calibration free due to an allowable floating baseline compensated for in the transition point algorithm. Integration of this sensor with an automated aliquoting machine will not only increase the productivity, but remove the health hazard associated with handling human blood samples and its components.