Assignment#01: Literature Survey on Sensors and Actuators ECE5320 Mechatronics Assignment#01: Literature Survey on Sensors and Actuators Topic: Breathalyzers (Breath Alcohol Content Sensors) Prepared by: Justin Horrell Dept. of Electrical and Computer Engineering Utah State University E: 3/11/2010

5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-2 Outline –Reference list –Major applications –Basic working principle –Law enforcement application –Major specifications –Electrochemical fuel cell specifications –Limitations –Choosing a breathalyzer –Cost information and variability –Models, cost and where to purchase

5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-3 Reference List

5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-4 Further Reference ile_id=0J astr.gsu.edu/hbase/chemical/electrochem.html

5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-5 Major Applications Principle technology to measure similar gasses, not just alcohol. Major applications of gas sensors are: –Law enforcement (alcohol) –Mining safety (methane) –CO detection –Air quality control –Hospitals

Basic Working Principle Several methods of detecting alcohol gas in breath: –Chemical reaction causing color change –Infrared spectroscopy –Electro-chemical Analysis (using a fuel cell) –Most common application is chemical reaction in a fuel cell, but we will explore all three. 5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-6

Basic Working Principle Chemical reaction causing color change –Breath is exhaled by the subject into the device –Alcohol is converted to liquid form by sulfuric acid –Mixture reacts with potassium dichromate to produce a color proportional to the alcohol content –Photocells convert the color difference from reacted mixture to an un-reacted sample to electrical current –Electrical current is converted to a digital display 5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-7

Basic Working Principle Infrared Spectroscopy –Used to identify various compounds within a sample –Molecules are identified based on IR interaction –Breath is exhaled into an laser tube –IR light is sent through the exhaled air –Optical band-pass filter is used to identify ethanol –Electrical current determines alcohol content based on the signal amplitude from the filter 5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-8

Basic Working Principle Electro-chemical Analysis –Breath is exhaled onto a fuel cell –Cell consists of two platinum leads with a porous layer between –Converts alcohol to acid –Creates free electrons –Free electrons are directly proportional to breath alcohol content. 5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-9

Law Enforcement Application Purposes for breathalyzer tests in law enforcement: –Local, state and highway police department road-side DUI determination and arrest –Jails and prisons for testing on inmates –Probation officers to ensure offenders are keeping to the terms of their probation –Work release programs within the prison system 5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-10

Law Enforcement Application Today’s technology relies mostly on Electro- chemical Analysis using fuel cells. Pros: –Specifically calibrated for human breath –Easy to maintain consistent measurement –Linear response –Low power consumption Con: –Limited sample amount unable to account for variance 5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-11

Major Specifications We will explore the BACtrack S80 Pro Breathalyzer –Commonly used in Law Enforcement –Quick response time –Accurate with even trace amounts of alcohol – 0.4 % Accuracy range (This is virtually the range from complete sobriety and death) –Accurate with even trace amounts of alcohol –Linear response –Durable and long lasting 5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-12

Major Specifications Specifications of the BACtrack S80 Pro: Requires Calibration Runs on two AA batteries. 5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-13

Electrochemical Fuel Cell BACtrack S80 Pro utilizes electrochemical fuel cell sensor technology as this figure shows 5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-14

Electrochemical Fuel Cell 5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-15 The correlation precision of the Peak Output at increasing gas concentrations:

Limitations Inaccurate readings following eating, drinking or smoking within 20 minutes of using the device Accurate temperature range is 0-40 C Requires calibration every 6-12 months Requires at least 5 seconds of air flow to ensure accuracy 5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-16

Choosing a breathalyzer Determination of which breathalyzer is right for you depends on your application. Professional such as law enforcement or hospitals should choose a breathalyzer which is –Accurate –Large range of accuracy –Electrochemical fuel cell fits these requirements Personal use must consider cost, and may choose a less accurate device 5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-17

Acquiring a Breathalyzer We will now go over several different devices which are available for purchase Consider cost and availability Determine how much accuracy you need versus cost Finally we will explore where to purchase a device 5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-18

FC20 Portable Breath Alcohol Analyzer Most accurate fuel cell Large size Moderate power Memory and printing % BAC Consumer: $1, Call: to order 5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-19

BACtrack S80 Pro Accurate Small size Wide range Low power 0.00 – 0.40 % BAC Consumer: $200 May purchase from the manufacturer: 5/16/2015 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators Slide-20