Download Toxin Detection Circuit (Title Work in Progress)

Detection of
Harmful Algal
Blooms (HAB)
Created By: Matthew Barboza
Supervising Professor: Dr. Sungyong Jung
Analog Mixed signal Integrated Circuits (AMIC)
Purpose
• Main Problem: Harmful Algal Blooms (HAB’s) posing a
threat to environment and local population.
• Current detection methods
o
o
o
o
Manual Sampling and Testing
accurate analysis – small areas, time consuming, after the event
Aerial Scanning
large area scan – uncertainties, may not be real-time
• Proposed Solution: Submerged array of sensors to
provide real-time, large area identification for early
warning and treatment
In Situ Wireless Sensing
Network (WSN)
Microsystin
sensors
•
Qualitative and quantitative analysis.
•
Easy to cover vast space and time.
•
Real time and in situ monitoring.
•
Early warning system.
Overview
• Background:
o Harmful Algal Blooms
o Immunoassays
o Optical Electronics, laser-diodes and PIN photodiodes
o Transimpedance Amplifiers
• Set-up
• Devices
• Progress
Harmful Algal
Blooms (HAB)
• What is a HAB?
o Sudden increase of marine microorganism population
• algae, bacteria
• Why is it “harmful”
o Hypoxic conditions (little oxygen)
o Toxins
• e.g. Microcystin LR produced by Microsystis Aerugenosa
Immunoassay
• A technique of identifying a substance by its ability to bind to an
antibody. - Collins English Dictionary
Laser Diodes
• Emission of light due to electron-hole recombination
• Monochromatic
• Narrow beam
Photodiode
•
•
•
•
•
Incident light causes electron-hole pairs
Carriers are swept across depletion region
Increase in reverse current
Current proportional to incident light
PIN , P-type, Intrinsic, N-type
Transimpedance
Amplifier (TIA)
• Input current signal Ii, output voltage signal Vo
• Amplifier gain is Vo/Ii (ohms)
Antibody – Antigen
Bonding Site
Photodetector
Laser Diode
Amplifier
Circuit
Immunoassay
Digitally Controlled
Pulsing
Memory
Microcontroller
Analog to Digital
Converter
Communication
Protocol
Wireless
Transmitter
Devices
•
•
•
•
•
FDS1010 – Photodetector – Thorlabs
D7805I – Laser Diode – Digikey
OPA380 – Transimpedance amplifier – Digikey
TiWi5 – Wireless
dsPIC33FJ128MC802 – Microcontroller – Mouser
Progress
• Microcontroller Configuration
o 25.3 ns Instruction cycle (98.8% of 40 MIPS)
o 39525652 Timer Interrupt ( ~ 1 second)
o Single, 10-bit, ADC conversion
•
K. G. Sellner et al., “Harmful Algal Blooms: Causes, Impact, and
Detection” in Society for Industrial Microbiology, Copyright © 2003
EBSCO Publishing, DOI 10.1007/s10295-003-0074-9