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

2. 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

3. 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

4. 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

5. Block Diagram

6. 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

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

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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! N/A
000035! N/A
000105! N/A
Motor Control
–works, can be altered using code
-implement different algorithm to signal end of data collection
Future Projects
Waterproof base
Wireless Integration

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

15. Questions?