Development Of Programmable Wireless Module For In Vivo Pressure And Temperature Monitoring

Abstract

The goal of this work is to fabricate a miniaturized, low power, bi-directional wireless communication system that can be used for in vivo pressure and temperature monitoring. The system prototype consists of miniature frequency shift keying (FSK) transceiver integrated with microcontroller unit (MCU) in one small package, chip antenna, and capacitive interface circuitry based on delta-sigma (SigmaDelta) modulator integrated with a on-chip temperature sensor. At the base station side, an FSK receiver/transmitter is connected to another MCU unit, which sends the received data or received instructions from a PC through a graphical user interface GUI. Industrial, scientific and medical (ISM) band RF (433 MHz) was used to achieve half duplex communication between the two sides. ShockBursttrade RF protocol has been used to achieve high data rate of 50Kbps. Gaussian frequency shift keying (GFSK) modulation scheme was adopted to ensure a reliable and high-speed digital RF link. A digital filtering has been used in the capacitive interface to reduce noise effects forming capacitance to digital converter (CDC). All the modules of the mixed signal system are integrated in a printed circuit board (PCB) of size 22.46times20.168 mm. The overall system supply voltage is 2.7V maximum