Mid-Semester Presentation February 28, 2012

Josh Gwinn Team Leader Programming Amplifier Circuit Lakeldren Williams Web Design Programming Robert Dale Mechanical Design Hardware Debugging James Akio Cotton PCB Design Hardware Debugging

 Problem  Solution  System Overview  Constraints Technical Practical  Bill of Materials  Improvements  Testing  PCB

 To further his research, Dr. Todd Mlsna with MSU’s Chemistry Department requires a concentrator that heats a sample before measuring alcohol content.

 CPTAM Heat sample Record temperature Pump mixture through alcohol sensor Record alcohol sensor Alcohol Sensor Alcohol Mixture Vacuum Pump Exhaust Capillary Tube

Data Storage Pump Temperature Sensor User Defined Parameters Alcohol Sensor Amplifier Circuit Microcontroller

NameDescription 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. MemoryThe temperature of the capillary tube and the alcohol content must be recorded three times per second for a programmable amount of time.

TypeNameDescription SocialSimpleThis device must be easy to set up and use by anyone with average technical skills. ManufacturabilityCustomizationUsers must be able to program heating temperature, collection time, and pump power.

 Must be able to set up and use with average technical skills A Research Device Multiple Users Differing Educations and Experiences [1]

 Customization Heating Temperature Collection Time Pump Power  Fine Tuning [2]

 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

MCP41050

 PCB Visual defects  Power Supply Test the various voltages ○ 5V regulator caused noise on the 12V rail Needed cap  Temperature Sensor

 Sensor returned 3A2F = 14,895  Temp = 14,895*0.02 – 273 = 24.9ºC

 Microprocessor Test the UART connections  Test heating of the tube Check voltage quality  Test the current sensing circuit Needed low pass filter  Pump Blown mosfet  Alcohol Sensor, Amplifier Circuit Verify that voltages are within 0-3.3V  VDIP1 Verify initialization checks

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]

 Power Traces 4 connectors 2 mosfets  Different Power Rails  Digital Potentiometer  Manual Potentiometer  Lm6484 Opamp

Power Traces

Digital Potentiometer

Lm6484 Opamp

 [1] Jackie Brown Medical. [Online]. Available: blog/tag/lab-technicians/. [Accessed September 27, 2011]. blog/tag/lab-technicians/  [2] CTI Career Search. [Online]. Available: lab-technicians. [Accessed September 27, 2011]. lab-technicians  [3] Newegg. [Online]. Available: [Accessed September 27, 2011].  [4] Omega. [Online]. Available: [Accessed September 27, 2011].  [5] Arstech. [Online]. Available: pwr3v.html. [Accessed September 27, 2011]. pwr3v.html  [6] Pololu. [Online]. Available: [Accessed September 27, 2011].  [7] Omega. [Online]. Available: [Accessed September 27, 2011].  [8] Digi-key. [Online]. Available: [Accessed September 27, 2011].  [9] Digi-key. [Online]. Available: [Accessed September 27, 2011].  [10] Digi-key. [Online]. Available: ND. [Accessed September 27, 2011]. ND

Mid-semester Presentation February 28, 2012