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CARSCellular Automotive Remote
System
Abhishek JainMike Charogoff
Matt LasekNguyen Le
Blair Harness
Objective
Effectively work in a group to produce a working prototype of a cellular automotive remote system. At expo the demonstration system will send and receive information via a cellular phone.
Functionality
Resembles OnStar More universal, many more and
different convenience features.
Through CARS the user can control: Starter Security system Heat and cooling system
Functionality
CARS obtains and sends information about: Temperature Theft Vehicle location Accidents
Optional Features
User obtains information via voice messagesControl movement of vehicle (prototype)Gives information of vehicle distance from userInformation received from car on a terminal PC or microcontroller
C.A.R.S.- System Overview
Audio Amp
Misc.Analog Inputs(Temp., Accelerometer)
GPSMisc. Digital Inputs
(Bumper, Optical Encoders,Door Switch, ..etc.
Speaker, Microphone, and Solenoids
MCU
(W/ ADC on-board)
Solenoid Driver,DAC and Audio Amp
Misc. Digital OutputsHeater, Door L/U, …etc.
Cellular Phone
Home or Cellular Phone
Audio Amp
MCU
(W/ ADC on-board)
Memory(RAM or Serial EEPROM)
LCD or Seriallink to PC
Memory(RAM or Serial EEPROM)
Vehicle“Home”
Wireless
Solenoid Driver,DAC and Audio Amp
Alternate implementation doesNot require solenoids, DAC,Or Speaker on Home system.
Speaker, Microphone, and Solenoids
Functionality OverviewVehicle-based system
MCUMCU
Digital InputsDigital Inputs ADC(For analog inputs)
ADC(For analog inputs) Digital OutputsDigital Outputs
GPSGPS
Door SwitchDoor Switch
Bumper Switch*Optional Feature
Bumper Switch*Optional Feature
Microphone(Audible tones are
amplified and converted
Microphone(Audible tones are
amplified and converted
Temperature SensorTemperature Sensor
Accelerometer(used to detect
Collision)
Accelerometer(used to detect
Collision)
Door Locked/U(LED used to represent door lock or hood release control)
Door Locked/U(LED used to represent door lock or hood release control)
Auto-Dial Control(These signals feeda driver circuit and
solenoids)
Auto-Dial Control(These signals feeda driver circuit and
solenoids)
Heater(Lamp used to representheater control and create
heat for temp. sensor)
Heater(Lamp used to representheater control and create
heat for temp. sensor)
DAC(For analog outputs)
DAC(For analog outputs)
Analog Tone(Amplified and fed to
speaker in orderto send data)
*Voice is optional
Analog Tone(Amplified and fed to
speaker in orderto send data)
*Voice is optional
Lights or horn Indicator(LED used to represent
Headlamps or horn)
Lights or horn Indicator(LED used to represent
Headlamps or horn)Optical Encoders*Optional Feature
Optical Encoders*Optional Feature
Motor Control*Optional Feature
Motor Control*Optional Feature
Functionality Overview“Home”-based system
MCUMCU
ADC(For analog inputs)
ADC(For analog inputs) Digital OutputsDigital Outputs
Microphone(Audible tones are
amplified and convertedto digital representation)
Microphone(Audible tones are
amplified and convertedto digital representation)
LCD (or Serial Bus)LCD (or Serial Bus)
Auto-Dial Control(These signals feeda driver circuit for
solenoids)
Auto-Dial Control(These signals feeda driver circuit for
solenoids)
DAC(For analog outputs)
DAC(For analog outputs)
Analog Tone(Amplified and fed to
speaker in orderto send data)
Analog Tone(Amplified and fed to
speaker in orderto send data)
Preliminary Board Layout
Preliminary Board Layout(And Mechanical Design of OPTIONAL Mobile Platform)
Tone Reception and Decoding
Audio Amp
Speaker, Microphone, and Solenoids
MCUPIC? 68HC1X?
(W/ ADC
on-board)
Solenoid Driver,DAC and Audio Amp
Cellular Phone
Principle of Operation1. Audible tones generated by the phone are converted
to an electrical signal by the microphone (transducer).2. This electrical signal is amplified and fed to an ADC.3. The digitized signal is decoded. The specific decoding method has
yet to be established, but one possible method would involve calculating the number of samples between zero crossings (or peak values). This number (n) would be unique for tones of different frequencies if the sample rate is adequate (> ~ 30k/sec).
4. After decoding, the Microcontroller executes the issued command (i.e. start vehicle, Lock doors, Unlock doors, …etc.).
(1)
(2) (LM380?)
(3)
(4)
Audio Amp
Speaker, Microphone, and Solenoids
MCUPIC? 68HC1X?
(W/ ADC
on-board)
Solenoid Driver,DAC and Audio Amp
Cellular Phone
Principle of Operation: (Very much the opposite of tone reception process)
1. The phone number of the “Home” station is stored in the cell phone so that the auto-dial function may be used. Two Solenoids are positioned (variable to accommodate various models) to push the appropriate buttons (thus calling the base).
2. The Vehicle-based system then waits for the Home station to transmit an initialization tone to be sure that it has “picked-up”. (Alternatively, Vehicle-based system waits for ringing to stop followed by a delay. This simplifies Home system, but may sacrifice reliability and features).
3. Now the Vehicle-based system may transmit by converting its stored data into an analog signal (via a DAC).
4. This analog signal is amplified (LM380/LM386?) and converted into sound by way of a small speaker (transducer).
Design Considerations:• Frequency response of Microphone and speaker.• Solenoid voltage/power requirement (12V?).• How standard is auto-dial on current generation cell phones?• (Audio) “cross-talk” between speaker and microphone.• How to hang-up? Another solenoid?• How much data may be stored on memory device of choice?
(1)
(2)
(3)
Tone Creation and Transmission
Stored DataEEPROM?SRAM?FLASH?
(4)
Solenoid Control
Principle of Operation:• A digital signal is used to control the
driver circuit.• Driver circuit consists of discrete
components or an IC. Current spikes and other large, inductive load concerns must be analyzed.
• Solenoid only needs to be energized for a fraction of a second in order to push the appropriate button. Overall power use should be relatively small.
MCU
Solenoid Driver
(L294/295 ?)
Solenoid
Cell Phone
(1)
(2)
(3)
Digital Inputs
GPS:• Take existing GPS device to track route of car. • Data consisting of longitude, latitude, and possibly distance or
speed of car sent via a serial data link to the microprocessor.Door Indictor:• Notifies home if user forgets to lock car door.• Implemented by a push-button switch, which will be pushed if
the door is locked and released if it is unlocked. Bumper Switch (Optional):• Use spring-loaded switch so that when demonstration car hits
an object the switch will be pushed. This will cause the car to change directions and avoid being stuck in one spot.
Optical Encoder (Optional):• Device will measure certain aspects of demonstration car such
operating speed, direction and will relay this information, in the form of digital pulses, to the microprocessor.
• Microprocessor will then use this data to control the car’s motion.
Optical Encoder(Optional)
GPS
Door Indicator
MCU
(W/ ADC on-board)
Bumper Switch(Optional)
To Rest of Block Diagram
Temperature Sensor:• A thermocouple or RTD (resistance temperature detector) will be
used to obtain a temperature reading inside and/or outside car. The measurement data will be sent to the user when the user gives the appropriate command.
Anti-Theft Device:• A vibration sensor, possibly piezoelectric, will be used to detect any
disturbances to the car. If a disturbance is detected, the data will be sent to the microprocessor which will alert the user.
Accident Alarm:• Consists of a combination of devices that notifies emergency
personal if the car is in an accident and gives them information about the location and severity of the accident. This will be done by using GPS (previously mentioned), accelerometer, and voice recordings. The accelerometer will give information about the magnitude of the accident and from this data will determine the severity of the crash.
Temperature
Anti-Theft Device
MCU
Accident Alarm
To Rest of Block Diagram
Analog Inputs
Heater/Air Conditioner:• Device will allow the user to warm/cool the interior of the vehicle
from home by use of cell phone• Heater will be implemented by use of a lamp which will be
activated by a switch (MOSFET, BJT).• Air conditioner can be realized by using a fan which would also be
initiated by a switch.LED’s:• The realization of the peripherals such as activating the door
lock/unlock, starter, headlamps, and horns used as the vehicle locater will be demonstrated using an array of LED’s.
Motor Control (Optional):• This device allows control of the demonstration car’s motion. It
does this by sending data to the car’s motor and wheels to control the car’s speed and direction.
Auto-Dial Control:• This device consists of a solenoid which pushes buttons on the
cell phone so that it can transit data.
Digital Outputs
MCU
To Rest of Block Diagram
HeaterAir Conditioner
Door Unlock/LockLights
Motor Control(Optional)
Auto-Dial Control
Division of Labor
Abhishek Jain-Digital OutputsMatt Lasek/Nguyen Le-Inputs (excluding audio features)Mike Charogoff –Audio Input/OutputBlair Harness-Programming, Micro-controller
Risks and Contingency Plans
Areas of risk: Microprocessor
Learning hardware/software use of micro controller Shouldn’t be an issue, several group members are
familiar with technology Button pusher
Ability to push (and possibly hold for speed dial) buttons Number of buttons we will need to push Plan on using solenoids for pushing buttons Multiple fixed solenoids vs single solenoid on servo drive
Audio quality needed for tone recognition Shouldn’t be a problem Add filters/amplification if needed
Risks and Contingency Plans
Areas of risk: Voice reply (optional)
Strings of digits sent back – requires ‘base station’ module
If possible, add voice reply Time vs quality considerations Number of messages needed
Storage requirements Accident alert thresholds
Should not report accident under hi-performance vehicle acceleration
Will need thresholds Might have to setup differently for different cars
Schedule
Summary
CARS convenience features include: Remote start/idle system Heat/Cool the interior of your car Lock/Unlock your car doors Anti-Theft System Accident Alarm System Temperature Sensor GPS
Questions?
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