Stand-Alone and Mesh Networks of Dissolved Oxygen (DO) Monitors Sd-May11-20 Betty Nguyen Scott Mertz David Hansen Ashley Polkinghorn Advisors Joseph Shinar Ruth Shinar with Bob Mayer Alex Smith

Background Applications Applications Waste water treatment Waste water treatment Chemical plants Chemical plants Fish farms Fish farms Fermentation lab Fermentation lab Monitoring water quality Monitoring water quality Saves energy Saves energy

Market Research Existing solutions: > $1000 HACH LDO Process Dissolved Oxygen Probe $1565 No remote capabilities Market: over 100 M

Project Objective Existing monitors and network Existing monitors and network Account for temperature variation Account for temperature variation Temperature sensor Temperature sensor DO level calculation modification DO level calculation modification Ensure functioning mesh network Ensure functioning mesh network Test integrated units Test integrated units Make necessary changes Make necessary changes Add new functionality Add new functionality

Conceptual Sketch

Functional Requirements Required The monitor units shall take readings of dissolved oxygen. The monitor units shall wirelessly transmit their readings to the master controller. The master controller shall request readings from each monitor unit. The master controller should have a graphical user interface to display measurements. The master controller user interface shall allow the user to poll a monitor unit for data. The system shall query each monitor unit for data through the master controller. The Windows service shall log all data processed through the unit in a SQL database. The network nodes shall create a star-like topology Optional The network nodes shall create mesh network topology The master controller shall send calibration data to each monitor unit.

Non-functional Requirements The system shall have an optimal operating range of 1000 meters. The microcontroller shall enter a sleep state between samples. A temperature probe shall be attached to the existing sensor probe to increase calculated accuracy.

Constraints Operating temperature: 0 to 50° Celsius. The temperature sensor must be accurate to ±1°C to satisfy this constraint. DO Monitor units need to be resistant to changes in temperature. Operating environment: water resistant. The probe should be resistant to water damage. Battery power is limited in sensor locations. The system needs to conserve as much power as possible when not measuring DO levels to ensure long battery life. Existing implementation uses Zigbee. Zigbee modules cannot route while in sleep mode.

Risks Circuit board redesign Encountering circuit issues frequently Existing design problems Sleep prevents mesh network from functioning Power is controlled by DO Monitor, not ZigBee node

Functional Decomposition

DO Monitor

Zigbee Node

Hardware Platforms AtxMega128 ZigBit Amp Custom DO Sensor Temperature Sensor: Temperature-to-Voltage TC1047

Test Plan: DO Sensor Temperature sensor Verify voltage levels from temperature sensor. Verify ADC conversion. Verify temperature constraint extremes. DO Sensor Verify DO sensor readings at room temperature. Verify DO sensor readings at various temperatures. Verify device enters and exits sleep mode

Test Plan: ZigBee Node Verify the ability of a ZigBee Node to receive a message. Verify the ability of a ZigBee Node to transmit a message.

Test Plan: NW Coordinator; Master Controller Network Coordinator Verify the ability of a Network Coordinator to receive a message. Verify the ability of a Network Coordinator to transmit a message. Master Controller Verify the ability of the Master Controller to send a command.

Test Plan: Integration Testing Verify communication between the Master Controller (PC) and Network Coordinator. Verify transmission of a command from the Network Coordinator to all ZigBee Nodes by verifying that the same command is read on all ZigBee Nodes. This is part of the star topology. Verify transmission of data from any ZigBee Node to the Network Coordinator by verifying the same data was received by the Network Coordinator. This is also a part of the star topology. [Optional] Verify a ZigBee Node is able to receive data from another ZigBee Node and able to pass it to the Network Coordinator. This makes a mesh network. Repeat steps with all command types.

Test Plan: System Testing Verify power usage when in OFF state. Verify the device enters sleep mode when not in use. Confirm the user interaction of pressing the “Take Sample Now” button in GUI will result in new measurement data from all DO monitor units. Confirm the user interaction ability to reconfigure coefficient calibrations on all DO monitor units.

Accomplishments Temperature sensor tested in hardware Hardware debugging Obtained necessary software stacks Some network testing Documentation clarified and expanded

Project Status MilestoneDescription Temperature HW Complete The temperature sensor will be integrated with the DO Monitor.X Design Document Complete Design document will be completed.X Temperature SW Complete Temperature readings should be accurate to ±1°C. DO readings should be adjusted using the coefficients for the correct temperature range. Mesh Network Functional The mesh network has been confirmed to be functional, and all errors have been corrected. Sleep Mode functional The unit has been confirmed to enter sleep mode, and it enters a decreased power use state. Mesh Network Temperature Calibration Expansion complete New values for temperature coefficients can be sent over the mesh network from the GUI to individual monitors, and the monitors can replace their coefficient tables.

Schedule

Resource Estimate NamePrice Voltage Regulator $ Diodes $ 6.00 Temperature Probes $ 6.00 ATXMega $ LED Drivers $ 8.00 Digital Supplies $ Zigbits $ LCD $ Other Parts $ Total $

Member Contributions David Hansen Extensive hardware critiquing and debugging Scott Mertz Hardware debugging Temperature sensor testing Betty Nguyen Network testing Setting up test framework Ashley Polkinghorn Network testing Setting up test framework

Next Semester… Building and testing two more boards Make Master Controller consistent with sleep mode design Possibly implement remote calibration Finish testing network components Finish implementing and testing temperature firmware Integration testing