Design of a Tethered Data Collection System Mike Beatty Advisor: Prof. James Hedrick Department of Electrical & Computer Engineering Union College Schenectady, NY

Objectives/Goals What is it? My senior project consists of the design and implementation of a tethered data collection system. The system will be used to collect, store and transmit data as taken from a sensor package. The sensors take data of different water properties including temperature, pH, dissolved oxygen, conductivity, salinity, redox, and depth. The system will be implemented in Ballston Lake, NY where it will be used for research purposes in the studying of the water column of this unique lake by the Union College Geology Department. The data taken from the sensors will be taken and compared to the depths. The system consists of a the sensor package which is connected to a microcontroller via an underwater cable. This cable is coiled in windings on a base that rests of the bottom of the lake and the windings are in turn moved via a motor that is also controlled by the microcontroller. The microcontroller is then connected to a fiber optic cable which takes the data from the microcontroller to a fiber optic modem on shore where the data can be downloaded. Communication between person and the microcontroller is also achieved through this fiber optic cable. Users Geologists, Biologists, Environmental Scientists Anyone who studies water quality… Purpose Measures water quality and other parameters temperature, pH, dissolved oxygen, conductivity, salinity, depth, redox Data collection, storage and transmission

Objectives/Goals Design Specifications Motivation behind design Data Collection & Transmission Motor Control Motivation behind design Research Current Method Other Options Study the water column for research purposes Currently no practical way of taking data over a long period of time Our system makes this possible Other systems available but cost is a premium

Background Information Ballston Lake Reason for interest Depth Meromictic Permanently stratified Anoxic (lacking oxygen) Interesting Water Column Important recreation location 130 ft. deep in parts

Block Diagram

Anchor/Buoy Systems Anchor system Buoy System Steel platform (3’ diameter) Motor Windings Electronics (Waterproof) Buoy System Contains sensor package Anchor system Keep system in place Steel platform (3’ diameter) Base for electronics Buoy System Contains sensor package Cable connects buoy system and anchor

Sensor Package Sensor Package Temperature, pH, dissolved O2, conductivity, salinity, depth, and redox Moves up through the water column taking samples every meter

Sensor Cable Cable 6-pin bulkhead cable Connects anchor with buoy Transmits Data from sensor package to electronics Voltage and ground wires included in cable Power 12 V DC needed to power sensors Runs through underwater cable

8051 Microcontroller Motor Control Data Transmission Motor Logic Forward/Reverse/ Brake Data Transmission UART0 & UART1 Collect/Store/Forward Polled Operation Level Contverter Motor Logic PWM Direction Brake Forward (1) (0) Reverse Electronics 8051 microcontroller Used for motor control – 3 ports Connection through underwater cable Reads data from sensors Write data to flash Maxim 232 Level Converter 8051 – TTL 0-5 V Sensor – RS232 +/- 10V (1)=+5 V (0)= 0 V

Motor Motor H-Bridge (55 V, 3 A) 12 V Releases cable so buoy and sensors move H-Bridge (55 V, 3 A) Motor control CMOS Logic Current Sensing Motor Keeps cable coiled Releases cable so buoy and sensors move Different motor for demonstration purposes

Fiber Cable/Linux PC Fiber Cable Linux PC 2 Optical Bit Drivers ~600 ft Linux PC Protocol Receive Data Fiber Optic Cable Data sent along from microprocessor to unit at shore Includes fiber optic modem

How it works…. Takes samples once a day (12:00 am) Minimal lake traffic at this time Microprocessor programmed to allow motor release a meter of cable at a time Once readings are taken, cable again released Continues until pressure reaches a certain level signaling near surface Returns to bottom and rests until next time of reading

Results/Conclusions Motor Control Data Collection & Transmission Future Projects Hydrolab H20 V2.20 (C)opyright 1995 Hydrolab Corporation SN-25720 Time Temp-C DOsat DOmg/L Redox Depth Trb-r Batt 000005! 19.70 180.6 13.88 445. 0.1 N/A 12.2 000035! 19.71 64.8 4.98 445. 0.1 N/A 12.2 000105! 19.71 56.7 4.36 445. 0.1 N/A 12.2 Motor Control –works, can be altered using code -implement different algorithm to signal end of data collection Future Projects Waterproof base Wireless Integration

Acknowledgements Prof. James Hedrick (Union College) Prof. George Shaw (Union College) Gene Davidson Jim & Roland (Machine Shop at Union College) Gautam Penumetcha (Silicon Laboratories)

Questions?