Development of a biotelemetry system with a microcontrolled sensing unit

This paper presents the development of a biotelemetry system comprising a microcontrolled sensing unit and a reading unit. Through the magnetic coupling between the coils of an inductive link, the reading unit is able to provide power and establish data communication with the sensing unit. A signal generator and a current driver in the reading unit allow energy transfer to the sensing unit, which has a microcontroller that performs the signal acquisition of a temperature sensor and sends the resulting digital data to the reading unit by means of a LSK modulator. The ASK demodulator of the reading unit retrieves the data that is processed by another microcontroller, which provides the measurement result to a computer over a serial communication interface. The results showed that the sensing unit operates at a coupling distance of up to 21 mm between the sensing and reading unit coils for a 9600 bps data communication rate, whereas the maximum achieved data rate was 38400 kbps for a coupling distance of 8 mm.