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School of Electrical and
Computer Engineering
Wireless Telemetry for Solar
Powered Car
Heather Chang
Farhan Farooqui
William Mann
November 1, 2010
Project Overview
Wireless
Data from
the Solar
Car to the
Chase Car
Design Features
• Real-time display of vital information:
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Solar panels
Voltage, Current, Power,
Battery packs
and Temperature
Motor
Vehicle speed
Motor torque
Motor controller status (on/off)
Vehicle location (GPS)
Outdoor and cabin ambient temperature
• Wireless link with solar car (at least 100 ft)
• GUI displaying data on LCD to driver and on
laptop in chase car
Design Overview
Current Status
• Established connection with the Single Board
Computer
• Ordered current (I) sensors, GPS, RF link and
Hall effect sensors
• In process of designing an alternate
temperature sensor circuit
Data Acquisition: Temperature
Temperature sensors
• Cabin Temperature
• Outside Temperature
Alternate Temperature Sensor
The MAX6627 Temperature sensor:
• Accuracy of ± 1°C in the 0°C to 125°C
range
• Operates in the -55°C to 125°C range
• Uses a 3.3 to 5 V supply
• Consumes 200 µA
• Connects through SPI bus
Data Acquisition: Vehicle Speed
• Two Part System
– Hall Effect RPM Sensor
– Magnet
Magnet
attached
to wheel
Wheel
RPM Sensor
Data Acquisition: GPS
• GPS Tracking
–Linux driver
–USB connectivity
–Longitude, Latitude,
Altitude, Speed
–5 ft long wire
Data Acquisition: Current (I) Sensor
HASS 200-S Sensor:
• Nominal current
of 200 A (rms)
• Measures up up to a range
of ± 600 A
• Low power consumption
(5V, 22 mA)
Current (I) Sensor Dimensions
• Aperture: 20.4 x 10.4 ± 0.5 mm
• Panel Mounting with M4 screws
in mm. 20 mm = 0.787 in.
RF Wireless Link
ZigBee USB module:
• Connects to both the SBC and the
laptop via a USB port
• Integrated 2.4GHz antenna
• Range is up to 150 m
• Consumes 147 mA in TX boost
mode and 26 mA in Power Mode 03
• Compatible with Linux
(MAC OS-9/-X, Windows 98SE/XP/2000)
• AT Style command interface
Jumper Board
• Ribbon cable
connection to SBC
• Protection circuitry
– Filters
– Opto-isolators
– Voltage regulators
• Development
– Proto board
• Final
– Soldered circuit board
On-board Computer
• Consumes 400 mA with a 5 V power supply
• Programmable using embedded C on a Linux
platform
Connection
Data Source
SPI Bus
Temp. Sensor
A-D Converter Current Sensor
USB
GPS Receiver
USB
RF Wireless Link
Digital I/O
RPM sensor
User Interface: Information Display
Driver cabin
Chase car
• Low power LCD display
• Stored in CSV (commaseparated values)
Advantages / Disadvantages
Advantages:
• The Telemetry system is an independent system
– Malfunction isolation
– Comparison of measurements
Disadvantages:
• More components needed
– Wires
– Standalone SBC
Project Schedule
Nov 10, 2010
SBC sensing all sensors
Nov 20, 2010
Laptop receiving data from the SBC
Nov 27, 2010
GPS system integrated
Dec 4, 2010
Graphical User Interface ready
Future Work
• Establish an interface among the ECE systems
– Battery packs voltage/current/temperature
measurements
– Solar arrays voltage/current/temperature
– Motor controller status
• Physical connections to solar car
• Develop useful user interface for Solar Jackets
Questions?