MicroElectronic Pill

TECHNICAL SEMINAR

INTRODUCTION

PARTS OF MEP

ISFET

SENSORS

CONTROL CHIP

RADIO TRANSMITTER

1

2

3

4

5

6

CONTENTS

7

9

8

10

11

12

CAPSULE

DESIGN AND FABRICATION

BIBLIOGRAPHY

ACCURACY AND RANGE

DISADVANTAGES

ADVANTAGES

The invention of the transistor enabled the first radio telemetry capsules.

These units could only transmit from a single sensor channel, and were difficult to assemble due to the use of discrete components.

Professor Jon Cooper and Dr Erik Johansson from Glasgow University, U.K developed modern microelectronic pill in 1972.

INTRODUCTION

BASIC PRINCIPLEMicroelectronic pill is developed for the detection of diseases where restricted access can prevent the use of traditional endoscope.

The electronic pill is a biocompatible capsule consisting of PEEK coating,ASIC control chip and discrete radio Tx.

Gives provision for exact pill location and its monitoring.

PARTS OF THE PILL

An ISFET is Ion-Sensitive Field-Effective Transistor used for measuring ion concentrations in a solution.

It can reveal pathological conditions associated with abnormal pH levels.

ISFET

The sensors are fabricated on two silicon chips located at the front end of the capsule.

Chip 1 comprises of temperature sensor, and a two electrode conductivity sensor.

Chip 2 comprises of oxygen sensor and an optional nickel-chromium (NiCr) resistance thermometer.

SENSORS

The ASIC is the control unit that connects together the external components of the micro system.

The DSP module conditions the digitized signals through the use of a serial bit stream data compression algorithm.

This minimizes the transmission length. ASIC & sensors consume 5.3 mW power corresponding to 1.7 mA of current.

CONTROL CHIP

CONTROL CHIP

The radio transmitter is assembled using discrete surface mountcomponents on a single-sided printed circuit board (PCB).

It has following functional features:

• Size of transmitter = 3 mm • Modulation Scheme = Frequency Shift Keying (FSK)• Data Transfer Rate = 1 kbps • Frequency = 40.01 MHz• Bandwidth of the signal generated -10 KHz• It consumes 6.8 mW power at 2.2 mA of current

RADIO TRANSMITTER

The microelectronic pill is a machined biocompatible (nontoxic), chemically resistant capsule.

The PCB chip carrier is made from two standard 1.6-mm-thick fiber glass boards attached back to back.

The ASIC is attached with double-sided copper conducting tape, sensor inputs, and the transmitter.

CAPSULE

Fabrication includes electroplating of thermally evaporated silver in Ag|AgCl electrodes.

The sensor lifetime is further extended using a three-electrode electrochemical cell for the oxygen sensor.

From this the overall current channeled through the reference was reduced by at least three orders.

FABRICATION AND RESULTS

The standard type 1 transmitter exhibited a negative linear frequency change from 39.17 MHz to -4 kHz.

The type 2 transmitter exhibited a positive linear frequency change from 20.07 MHz to 0.9 KHz.

The electromagnetic noise baseline is measured to be 78 dB of S/N in the 20 MHz band.

TRANSMISSION

OBSERVATIONS

Observations on receiver computer

•2 SR44 Ag2O batteries are used. •Operating Time > 40 hours.•Power Consumption = 12.1 Mw•Corresponding current consumption = 3.9mA •Supply Voltage = 3.1 V

Accuracy

•pH channel is around 0.2 unit above the real value • Oxygen Sensor is ±0.4 mgL. • Temperature & Conductivity is within ±1%.

•Temperature from 0 to 70° C •pH from 1 to 13 •Dissolved Oxygen up to 8.2 mg per liter •Conductivity above 0.05 mScm-1 • Full scale dynamic Range analog signal = 2.8 V•Oxygen sensor is ±0.4 mgL•Temperature and conductivity within ±1%

RANGE

It is a MAGIC PILL FOR HEALTH CARE.

Adaptable for use in corrosive environment.

It can be used in industries for evaluation.

Power consumption is very less.

It has very small size, hence easy for practical use.

Less transmission length & hence has zero noise interference.

High sensitivity, good reliability and life time.

ADVANTAGES

It cannot perform ultrasound & impedance tomography.

Cannot detect radiation abnormalities.

Micro Electronic Pills are expensive.

Still its size is not digestible to small babies.

DISADVANTAGES

The application will be widened by following : Identification of tissue inflammation, ulcers, the activity of fermenting bacteria, glucose and lactate sensing etc.

Will be used for measuring water and salt absorption level.

Enables a variety of syndromes to be investigated including the growth of bacteria with low oxygen tension.

FUTURE SCOPE

Developed an integrated sensor array system which has been incorporated in a mobile remote analytical microelectronic pill.

The generic nature of the microelectronic pill makes it adaptable for use in corrosive environments.

In the future, one objective will be to produce a device, analogous to a micro total analysis system (TAS).

CONCLUSION

WEB REFERENCE:- • http://ubimon.doc.ic.ac.uk/bsn/public/Jon_Cooper.pdf• http://citeseerx.ist.psu.edu• http://www.forumsains.com

BOOK REFERENCE:-

• S. Mackay and B. Jacobson, "Endoradiosonde," Nature, vol. 179, pp. 1239-1240, 1957.

• H. S. Wolff, "The radio pill," New Scientist, vol 12, pp. 419-421, 1961.

BIBLIOGRAPHY

Thank You!