IMS BasedExplosive Detector

Presented By: Abhinav Biswas, CSE, GET - 140811 Rahul Saxena, ECE, GET - 140935 Nishant Kumar Sharma, ECE, GET -

140921

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

What is IMS ? An analytical technique to identify gaseous

Ionized molecules based on their Mobility or Drift velocity.

Ion Mobility Spectrometry:

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

What is IMS ?Ion Mobility

Spectrometry: Drift Tube

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

Objective

Collect & Analyze drift tube output Detect the sample material

Explosives like RDX, TNT.

Data Acquisition & Display Unit :

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Schematic Overview

Drift TubePre-Amplifier

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

Input Current

In picoamperes (pA)

Output Signal In millivolts (mV)

Schematic Overview

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

ADC

Pre-Amplifier

Analog to Digital Conversion

THS1206 ADC by Texas Instruments

12 bit, 6 MSPS Conversion Clock

100 kHz Filters

Drift Tube

AT91SAM9263 by Atmel

ARM9 Architecture 32-bit RISC 256 MB NAND Flash 64 MB RAM RS232 Serial Port

Schematic Overview

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

ADC

Pre-AmplifierDrift Tube

ARM

Schematic Overview

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

ADC

Pre-AmplifierDrift Tube

ARM LCD

Touch Screen Display

3’5” LCD 320 X 240 Resolution Resistive Touch

Data AnalysisUsing Matlab :

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

ADC Output data Containing Noise

Window Size – 50 Moving Average

Algorithm

Filter RequirementAliasing Problem:

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Nyquist Criteriafs >= 2 * fm

Anti-Aliasing Low-Pass Filter

Filter Selection

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High Order Butterworth

NoLinear Phase

Ripple ok

Narrow Transition

Band

Yes Yes

FIR Other Filters

No No

Yes

Low Order Butterworth

Filter DesignButterworth Filter:

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

Maximally flat pass-band response Better rate of attenuation Good all-around performance Easy to implement

Filter DesignUsing LTC 1064-2 IC :

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

D 2

1 N 5 8 1 7 M / C Y L

D 3

1 N 5 8 1 7 M / C Y LC 1C

C 2C

1

2

3

4

5

6

7 8

9

10

11

12

13

14

LTC 1064-2

NC

NC

NC

NCVin

AGND

AGND

V+

RinA

Vout

50/100

fclk

V-

OUTCV+ V-

V+

OUTPUT

8th order Butterworth filter (70-100kHz fc)

Variable Cut-off frequency – by changing clock

Filter DesignClock Generation :

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

555 Timer IC 50% Duty-cycle Variable clock

frequency – by changing Resistance value

C 1C

C 2C

D 1

D I O D E

R 1R E S I S TO R

R 2R E S I S TO R

1

2

3

4

5

6

7

8

555 TIMER IC

Vcc Reset

Discharge

Threshold

Trigger

Ground Control

Out f(clk)

180 pF

10 nF

Vcc

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

Filter DesignUsing Sallen-Key Filter: Why Sallen-Key

Topology ? 8th Order

Butterworth Low-Pass Filter

Very high Q-Factor – 2.5

Porting Linux on the ARM board U-Boot Bootstrap Kernel 2.6.30 Root File System

Development of device drivers for ADC IMS App using Qt 4.5

Qwt library for Graphs Cross-Compilation of Qt & Touch-screen

libraries

SoftwareOperations:

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

IMS AppHow it works : Graph Plot of

sample dataPeak DetectionCalculation of

Drift Time

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

Graph Plot Moving Average

AlgorithmWindow Size –

50 samples

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

Removal of Glitches :

Graph Plot Moving Average

AlgorithmWindow Size –

50 samples

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

Removal of Glitches :

Graph Plot Step-by-Step

ProcessWindow Size –

50 samplesPeak of each window

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Peak Detection :

Graph Plot Step-by-Step

ProcessWindow Size –

50 samplesPeak of each windowChange of sign/slope

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Peak Detection :

Conclusion

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

Analysis of ADC data Filter design Implementation in hardware

Development of IMS App Moving Average algorithm Peak detection algorithm

Ongoing Work:

Future Work: Final Deployment Android version

Thank You !

Corporate Research and Development , CR&DElectronics Corporation Of India Limited, Hyderabad

Special Thanks to :Smt. Lakshmi Latha SM, CR&DECIL Hyderabad