fab lab instrumentation reality—from lab to field

Debabrata GoswamiChemistry & Center for Laser TechnologyIIT Kanpurdgoswami@iitk.ac.in

Current Scientific Instruments are very expensive and highly specialized

Communities that would benefit fromthe use of instrumentation are unable toobtain it

Fab-Labs can be used to design and develop equipment and instrumentation for these communities

Consumer electronics make it possible to develop cheaper instrumentation

Redesigning existing instruments allows lower costs and increased flexibility without lowering performance

UV-Vis Spectrometer

Estimated Cost of $100

RF AnalyzerEstimated Cost

of$100

High Cost, High Sophistication Difficult to use in Field under Rugged environments

UV-Vis Spectrometer: Commercial Cost ≥ $500

Basis of All Linear Absorption Spectroscopy

▪ I=I0exp(-cL) UV-Visible & near-IR

(250 – 1000 nm)▪ Needs scanning of

individual wavelengths▪ Slow▪ S/N Issues

FTIR Measure in Fourier Domain

(perform time-domain measurements) & FT into wavelength domain

I0 I

Spectrum

UV-Vis with consumer electronics Commercially Available UV-Vis

Milk Analysis

Postal Mail

Spectrometry

Remote MedicalAssistance

Distance Learning

Food Quality Analysis Water Quality Analysis

Soil Analysis Agriculture AnalysesMedical Analyses

impulse response(complex frequency

response)DC – MHz~Rs.100

food/water quality, agricultural inputs, ...

580 590 600 610 620 6300.0

0.1

0.2

0.3

0.4 Shaped Pulse Original Pulse

Pho

todi

ode

Sig

nal (

V)

Wavelength (nm)

RF Driving Signal

Undeflected Beam

An Acousto-Optic-Modulator based Pulse Shaper setup with the help an amplified laser system. A couple of representative graphs of the pulse shaping capability is shown in the data that are collected in the wavelength and time-domain respectively.

Laser Pulse In

Shaped Pulse Out

Acousto-Optic Modulator

Schematic

Femtosecond Pulse Shaper

0 200 400 600 800

0

100

200

300

400Fl

uore

scen

ce In

tens

ity (a

rb. u

nit)

Time (sec)

Fluorescence Signal Step function Fit

Speed: Since all of the frequencies are measured simultaneously, most measurements are made in a matter of seconds

Sensitivity: Sensitivity is dramatically improved with FTIR The detectors employed are much more sensitive, the optical

throughput is much higher which results in much lower noise levels, and the fast scans enable the co-addition of several scans in order to reduce the random measurement noise to any desired level

Mechanical Simplicity: The moving mirror in the interferometer is the only continuously moving part in the instrument Very little possibility of mechanical breakdown

Fingerprint Region: Sensitive characterization possible

Micro- and nanoscale prototyping of programmable assembly systems

Theoretical principles for physical computation ("formatics")

Platforms for distributed control of embedded networked devices

Smart tools with feedback control Machines that can make machines Open-source engineering design tools

Visit: http://home.iitk.ac.in/~dgoswami.html

• Prof. Neil Gershenfeld, CBA, MIT• Prof. S.G. Dhande, Director, IITK

Acknowledgements