DISSOLVED OXYGEN MONITOR TEAM MEMBERS: ANDREW BEOUGHER ANTHONY SWOPE HAO WANG I-CHUN CHAO BING BAI COLIN HICKS Senior Design Dec1211 Dec1211

DISSOLVED OXYGEN MONITOR Measures the concentration of dissolved oxygen (DO) Uses the photoluminescence (PL) of a Platinum-Octaethyl-Porphyrin (PtOEP) Polystyrene film Major components: Sensor Control Unit (SCU) Sensor Probe Dec1211

DISSOLVED OXYGEN MONITOR Applications Waste water treatment Marine ecologies Fermentation Dec1211

DESIGN OBJECTIVES Re-engineer current design by removing or changing existing components. Lowering power consumption Adjusting system timing of the sensor Dec1211

DESIGN REQUIREMENTS Functional Water proof sensor probe, water resistant SCU enclosure Measurement range of 0-20ppm DO Local and remote control operation Microcontroller shall determine the dissolved oxygen level over 1 second Long battery life during discontinuous operation 5 samples every 5 minutes Operating duration of at least 30 days Probe: Submersible to 100 ft. Operational range of 0-50ºC Dec1211

DESIGN REQUIREMENTS Non-functional Local multi-character LCD Indicator lights Handheld / Portable Dec1211

SYSTEM CURRENT DESIGN Dec1211

SYSTEM PROPOSED DESIGN #1 Dual Supply System Dec1211

SYSTEM PROPOSED DESIGN #2 Single Supply System Dec1211

SYSTEM SIGNAL AMPLIFICATION Previous design Dec1211

SYSTEM SENSOR PROBE Photodiode Pre-amp Current to Voltage 4 LED’s 525nm LED driver Temperature sensor Dec1211

SYSTEM SENSOR PROBE Dec1211

SOFTWARE OPERATING THEORY Dec1211

SOFTWARE CURRENT SENSOR TIMING Dec1211

SOFTWARE PROPOSED SENSOR TIMING Dec1211

HARDWARE PROPOSED COMPONENTS Microcontroller ATXMega128 LED Current Driver MAXIM3699 TPS61042 LT1932 DC-DC Converters ADP150/151 TPS61006 MAX1763 Dec1211

HARDWARE LED DRIVERS Dec1211

HARDWARE LED CURRENT DRIVERS Why drive with current and not voltage? Dec1211

HARDWARE LED CURRENT DRIVERS Benefits of constant current Can provide a more accurate representation of power consumption LEDs will not burn out due to over current Constant luminosity of LEDs for accurate readings Dec1211

HARDWARE DC-DC CONVERTERS Output voltage of 3.3 V: ADP150/ µA quiescent current with 0 load Requires minimum 3.7 V TPS61006 Can operate as low as 0.8 V Low battery indicator ~50 µA quiescent current with 0 load MAX1763 ~88% efficient at input voltage of 1.2 V Dec1211

HARDWARE BATTERY CONFIGURATIONS 3 potential configurations Dec1211

HARDWARE BATTERY CONFIGURATIONS Issues of parallelism: Can increase available Amp hours One side becoming a sink or source Need to keep levels equal Use a diode to help regulate levels Performance benefits of using batteries in parallel Cost of power loss through diodes Benefit of increased Amp hours Dec1211

HARDWARE BATTERY CONFIGURATIONS Dec1211

TESTING COMPONENTS Power System: Power efficiency Current output LED driver: Startup times PWM output Actual vs. computed current output Microcontroller: Power consumption of different modes Dec1211

TESTING POWER SYSTEMS Test individually to derive accurate representation of the current used. Monitor the current drawn by the supplies in various modes of operation. Dec1211

From tps61006 data sheet. TESTING LED SYSTEM Speed test for start times Check the output wave form for ripple Dec1211

TESTING MICROCONTROLLER Test the current use in different modes Data Collection Calculation Idle Mode Power-Down Mode Dec1211

TESTING SYSTEM Full System Test: Long term battery duration Dec1211

TESTING SYSTEM Dec1211

PROJECT CURRENT STATUS Evaluate system operation Update customer requirements Perform component testing Create preliminary circuit board revisions Dec1211

PROJECT CONTRIBUTIONS Andrew Beougher Group leader, soldering, parts ordering, Cy-point server, organize meetings, edit and finalize documentation Anthony Swope Weekly reports, testing power supply components, sensor probe design Hao Wang Updating website, testing power supply components Dec1211

PROJECT CONTRIBUTIONS I-Chun Chao Research the LED driver parts and do the marketing research Bing Bai Improve the performance of current software design, develop testing program on different operation mode. Colin Hicks Production of documents, research of parts, design of test conditions, investigation of wireless communication. Dec1211

PROJECT FUTURE PLANS Finalize new circuit board version Assemble new circuit board Perform long term battery duration tests Perform application and calibration testing Test programming modifications Re-integrate wireless communications Dec1211

Questions? Dec1211