Many Test stations are to be developed along the coastlines to help fishermen. The test station will be able to detect bio-toxin in sea-foods and upload the necessary information such as location, date, type of sea-foods, level of contamination etc. in a secured website accessible to public.

1. Draw the block diagram representation of the testing station.
2. The sensor node is based on a highly sensitive interdigital sensor. The sensor is operated from 1 Vp-p, 100 Hz A.C. supply. What are the different components required to interface the sensor with the embedded processor? Explain with proper diagram.
3. The interdigital sensor has a capacitance value of 0.01 mF. Find a suitable value of series resistance across which the output signal is obtained. Find the expression of the output signal voltage in terms of other parameters. Provide the necessary circuit diagram.
4. The capacitor increases to 0.012 mF when the sample is contaminated to highest level of bio-toxin. Design an amplifier circuit with large noise rejection to obtain 3.3 V rectified voltage to interface the signal to processor. Find the necessary gain and the external resistance of the amplifier. Provide necessary circuit diagram.