Development of a biotelemetric heart valve monitor using a 2.45 GHz transceiver, microcontroller, A/D converter, and sensor gain amplifiers

The development of a fully implantable micromachined device that uses biotelemetry to monitor beat-to-beat aortic flow through artificial heart valves has been proposed. The purpose of this research was to design and build a large-scale circuit that could prove the feasibility of the essential concepts involved in such a device. The objectives were to demonstrate the ability to acquire and condition data signals with a microcontroller, show the capability to interface the microcontroller to a transceiver IC, RF transmit the acquired data to a PC, and successfully recreate the captured signals with the data received by the PC. The final design is composed of a PIC16C76 microcontroller, the MicroStamp Engine 2.45 GHz transceiver IC, and two AD620 low power instrumentation amplifiers. This is the highest frequency evaluated for a biotelemetry system known to the authors. The circuit performs an 8-bit A/D conversion on two input channels and serially relays the converted data to the MicroStamp Engine, which transmits the data to a PC at 2.45 GHz. The system was tested using triangular wave input signals of various frequencies and amplitudes. The results showed an average of 4.1% error per reproduced waveform