Solar Car Data Collection System Matt Boyden Rene Dupuis Ryan Lavallee 4/23/08

Ryan Background Building miniature solar cars is a very common activity for teaching school-age kids about renewable energy Building miniature solar cars is a very common activity for teaching school-age kids about renewable energy There are events specifically designed for building and racing solar cars that are available as educational kits There are events specifically designed for building and racing solar cars that are available as educational kits

Ryan Project Description What is needed is a small, light data logging device specifically designed to interface with a typical educational solar car kit. What is needed is a small, light data logging device specifically designed to interface with a typical educational solar car kit. The data collection system will collect data on voltage, current and speed, every ½ second. The data collection system will collect data on voltage, current and speed, every ½ second. The data will allow educators to output graphs of distance, speed, acceleration, voltage, current, power and energy vs. time. The data will allow educators to output graphs of distance, speed, acceleration, voltage, current, power and energy vs. time.

Ryan Project Requirements Record voltage and current to the motor for a specific amount of time Record voltage and current to the motor for a specific amount of time Interface with a computer to easily output the information in a way that can be used for educational purposes Interface with a computer to easily output the information in a way that can be used for educational purposes The product must be light enough and use little power so as not to significantly change the performance of the car The product must be light enough and use little power so as not to significantly change the performance of the car

Matt System Diagram

Matt System Diagram Data Collection

Matt System Diagram Data Output

Matt Design Outline Speed, Current and Voltage Sensing Speed, Current and Voltage Sensing Microcontroller Programming Microcontroller Programming The User Interface The User Interface Circuit Board Design and Layout Circuit Board Design and Layout Enclosure Design Enclosure Design Project Management Project Management

Speed, Current, and Voltage Sensing Rene

Rene Velocity Sensor Concept   Every time the wheel rotates the sensor triggers the Pulse Accumulator in the microcontroller  By knowing the wheel circumference and reading the accumulator value at regular time intervals we can calculate the speed of the car

Rene Reflective Object Sensor Consists of an infrared emitting diode and NPN silicon phototransistor mounted side by side Consists of an infrared emitting diode and NPN silicon phototransistor mounted side by side Phototransistor responds to radiation emitted from diode when it senses a reflective device Phototransistor responds to radiation emitted from diode when it senses a reflective device Provides Provides High output sensing no reflection High output sensing no reflection Low output sensing reflection Low output sensing reflection

ReneComparator Velocity sensor output runs into comparator Velocity sensor output runs into comparator Eliminates hysteresis and rise times when changing states (high to low; low to high) Eliminates hysteresis and rise times when changing states (high to low; low to high) Provides quick transition intervals as comparator changes states Provides quick transition intervals as comparator changes states Provides sure output Provides sure output

Rene Comparator Simulation

Rene Velocity Sensor Circuit

Rene Current Sensing Use Resistor to measure current to motor Use Resistor to measure current to motor 0.15Ω resistor will not affect motor performance 0.15Ω resistor will not affect motor performance Easy to install in series with clip leads Easy to install in series with clip leads Voltage will be amplified x30 and converted to positive voltage before A-D converter Voltage will be amplified x30 and converted to positive voltage before A-D converter

Rene Voltage Sensing Voltage will be read directly off of the panel with an A-D convertor. Voltage will be read directly off of the panel with an A-D convertor. The voltage and current values will also be used to calculate power and energy The voltage and current values will also be used to calculate power and energy

Microcontroller Programming Matt

Matt Microcontroller Programming We will use a Motorola HC12 microcontroller We will use a Motorola HC12 microcontroller What does the Program have to do What does the Program have to do Data Transmission to PC Data Transmission to PC

Matt The HC12 Has Analog to Digital Converters Has Analog to Digital Converters Has RS232 Chip Built into Module Has RS232 Chip Built into Module 16kB Flash Memory for Data 16kB Flash Memory for Data Easily programmed using available software Easily programmed using available software Can be programmed on docking module then transferred to application Can be programmed on docking module then transferred to application

Matt Program Requirements → On Request: → Read Data from A2D Ports (Voltage and Current) → Read Data from Wheel Sensor (Speed) → Store Data to Flash Memory → On Request or Timeout: → Stop Recording Data → On Request: → Transfer Data to Computer → Erase Memory

Matt Data Transmission Current, Voltage and Speed information is sent one number at a time through an RS232 connection Current, Voltage and Speed information is sent one number at a time through an RS232 connection We are using Hyper Terminal to receive the data and capture it to a text file We are using Hyper Terminal to receive the data and capture it to a text file From here, the data will be available on a PC to be accessed by the VBA program From here, the data will be available on a PC to be accessed by the VBA program

The User Interface Ryan

Ryan PC Programming How the Excel Program Works How the Excel Program Works User Interface User Interface Outputs Outputs

Ryan How VBA Program works Program references.txt file Program references.txt file Places.txt file in predefined rows Places.txt file in predefined rows Excel programmed to make calculations and produce graphs of all the data Excel programmed to make calculations and produce graphs of all the data Calculations: Calculations: Voltage Cell: A2D_V * Voltage Cell: A2D_V * Current Cell: ((A2D_I*0.0049)/30)/0.15Ω Current Cell: ((A2D_I*0.0049)/30)/0.15Ω Velocity: (PA(t) – PA(t-1)) * Wheel circumference Velocity: (PA(t) – PA(t-1)) * Wheel circumference 0.5 seconds 0.5 seconds Automates graph wizard process for all data Automates graph wizard process for all data

Ryan User Interface

Ryan Outputs Each graph will be displayed on a separate page in Excel Each graph will be displayed on a separate page in Excel

Circuit Board Design and Layout Ryan

Ryan Board Layout Methodology Circuit Circuit Circuit This is the circuit board that we designed. This will contain the Microprocessor, and any circuitry required. This board must be small enough to fit on the solar car and as light as possible.

Case Design Rene

ReneDesign

Design Dimensions

Project Management Matt

Responsibilities Ryan Ryan Data Retrieval (PC end) Data Retrieval (PC end) Excel VBA Programming Excel VBA Programming Circuit board layout Circuit board layout Matt Matt Signal conditioning HC12 programming, Data transmission to PC (HC12 end) Rene Rene Wheel sensing design Wheel sensing design Power Distribution Power Distribution Casing Prototype Casing Prototype Website Website

RyanSchedule

Matt Budget Item Cost CostActualCost HC12$30$0 Solar Car $50$50 Reflective Sensor $2.86$0 3V Lithium Battery (2) $1.98$0 Op-amp TLV 2772 (3) $6.75$6.75 Ribbon Cable(2) $10.00$10.00 Comparator$1.74$1.74 Resistors, LEDs, Pushbuttons etc $20.00$0 TOTAL$123.33$68.49

Matt Next Steps in the Design Process Write our own communications program instead of using Hyper Terminal Write our own communications program instead of using Hyper Terminal Finalize casing with smaller and lighter components Finalize casing with smaller and lighter components Use ‘power saving’ options on HC12 to lower power consumption and improve battery life Use ‘power saving’ options on HC12 to lower power consumption and improve battery life Meet with educators Meet with educators

Questions?

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