CHEMICAL PRE-CONCENTRATOR FOR TRANSDERMAL ALCOHOL MONITORING (CPTAM) Mid-Semester Presentation February 28, 2012
Jan 18, 2016
CHEMICAL PRE-CONCENTRATOR FOR TRANSDERMAL ALCOHOL
MONITORING(CPTAM)
Mid-Semester Presentation
February 28, 2012
TEAM MEMBERS
Josh GwinnTeam LeaderProgramming
Amplifier Circuit
Lakeldren WilliamsWeb Design
Programming
Robert DaleMechanical Design
Hardware Debugging
James Akio CottonPCB Design
Hardware Debugging
OUTLINE
Problem Solution System Overview Constraints
TechnicalPractical
Bill of Materials Improvements Testing PCB
PROBLEM To further his research, Dr. Todd Mlsna
with MSU’s Chemistry Department requires a concentrator that heats a sample before measuring alcohol content.
SOLUTION CPTAM
Heat sampleRecord temperaturePump mixture through alcohol sensorRecord alcohol sensor
Alcohol Sensor
AlcoholMixture
Vacuum Pump
Exhaust
Capillary Tube
SYSTEM OVERVIEW
Data Storage
PumpTemperature
SensorUser DefinedParameters
Alcohol Sensor
Amplifier Circuit
Microcontroller
TECHNICAL CONSTRAINTSName Description
Temperature of Capillary Tube The temperature of the capillary tube must be maintained at ± 20ºC of the user-defined temperature.
Temperature Sensor Range The temperature sensor must be able to sense temperatures ranging from 15ºC to 200ºC.
Power Supply The CPTAM must operate from a standard 120V wall outlet.
Accuracy The CPTAM must record the alcohol sensor output within a 5% degree of accuracy.
Memory The temperature of the capillary tube and the alcohol content must be recorded three times per second for a programmable amount of time.
PRACTICAL CONSTRAINTSType Name Description
Social Simple This device must be easy to set up and use by anyone with average technical skills.
Manufacturability Customization Users must be able to program heating temperature, collection time, and pump power.
SOCIAL Must be able to set up and use with
average technical skillsA Research DeviceMultiple Users Differing Educations and Experiences
[1]
MANUFACTURABILITY Customization
Heating TemperatureCollection TimePump Power
Fine Tuning
[2]
BILL OF MATERIALS
BILL OF MATERIALS
IMPROVEMENTS
60A MosFet’s Temperature Sensor
Narrower field of View Added surface mount resistors for
precision Removed current limiting resistors Added current sensing resistor
Removed optional paths for current Digital Potentiometer and Opamp
DIGITAL POTENTIOMETER AND OPAMP
MCP41050
TESTING PCB
Visual defects Power Supply
Test the various voltages○ 5V regulator caused noise on the 12V rail
Needed cap
Temperature Sensor
INFRARED SENSOR I2C
Sensor returned 3A2F = 14,895 Temp = 14,895*0.02 – 273 = 24.9ºC
TESTING Microprocessor
Test the UART connections
Test heating of the tubeCheck voltage quality
Test the current sensing circuitNeeded low pass filter
PumpBlown mosfet
Alcohol Sensor, Amplifier Circuit Verify that voltages are within 0-3.3V
VDIP1Verify initialization checks
VDIP1
From hex to ASCII:09h 20h 74h 65h 73h 74h 2Eh 63h 73h
76h 0Dh
[Tab][Space] t e s t . c s v [CR]
PCB
Power Traces4 connectors2 mosfets
Different Power Rails
Digital Potentiometer
Manual Potentiometer
Lm6484 Opamp
PCB
Power Traces
PCB
Digital Potentiometer
PCB
Lm6484 Opamp
REFERENCES [1] Jackie Brown Medical. [Online]. Available:
http://www.jackiebrownmedical.ie/medical-jobs-blog/tag/lab-technicians/ . [Accessed September 27, 2011]. [2] CTI Career Search. [Online]. Available:
http://www.citytowninfo.com/employment/medical-lab-technicians . [Accessed September 27, 2011]. [3] Newegg. [Online]. Available:
http://www.newegg.com/Store/SubCategory.aspx?SubCategory=58&name=Power-Supplies. [Accessed September 27, 2011].
[4] Omega. [Online]. Available: http://www.omega.com/Heaters/pdf/fgr.pdf. [Accessed September 27, 2011].
[5] Arstech. [Online]. Available: http://www.arstech.com/item-External-Power-Supply-3-3V-pwr3v.html. [Accessed September 27, 2011].
[6] Pololu. [Online]. Available: http://www.pololu.com/catalog/product/1061. [Accessed September 27, 2011].
[7] Omega. [Online]. Available: http://www.omega.com/pptst/IRCO_CHAL_P13R_P10R.html. [Accessed September 27, 2011].
[8] Digi-key. [Online]. Available: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=MAX6675ISA%2B-ND. [Accessed September 27, 2011].
[9] Digi-key. [Online]. Available: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=LM741CNNS-ND. [Accessed September 27, 2011].
[10] Digi-key. [Online]. Available: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=LTC1051CN8%23PBF-ND. [Accessed September 27, 2011].
CHEMICAL PRE-CONCENTRATOR FOR TRANSDERMAL ALCOHOL
MONITORING(CPTAM)
Mid-semester Presentation
February 28, 2012