Wireless Data Wireless Data Acquisition for SAE Acquisition for SAE CarCar

Project by:Project by:J.P. Haberkorn & Jon TrainorJ.P. Haberkorn & Jon TrainorAdvised by:Advised by:Mr. Steven GutschlagMr. Steven Gutschlag

Presentation OutlinePresentation Outline

Project OverviewProject Overview– Functional DescriptionFunctional Description

Hardware DescriptionHardware Description– Wireless TransceiversWireless Transceivers

Software DescriptionSoftware Description Current ProgressCurrent Progress Future WorkFuture Work

SAE Formula CarSAE Formula Car

Ongoing Senior Ongoing Senior Design Project at Design Project at Bradley UniversityBradley University

Needs a system Needs a system that can track the that can track the car’s behavior in car’s behavior in real time and record real time and record data for future data for future analysis. analysis.

Benefits of SystemBenefits of System

Accurate data loggingAccurate data logging Stored in Excel SpreadsheetStored in Excel Spreadsheet Safer for car driverSafer for car driver Real time viewingReal time viewing

Wireless Data SystemWireless Data System

Use the EMAC 80515 to interface with Use the EMAC 80515 to interface with the sensors on the car.the sensors on the car.

Transmit the data wirelessly to a Transmit the data wirelessly to a laptop computer and store it for laptop computer and store it for further analysis.further analysis.

Use the Aerocomm AC4790-20 Use the Aerocomm AC4790-20 Wireless Transceivers.Wireless Transceivers.

Update the laptop frequently to Update the laptop frequently to observe and record car behavior.observe and record car behavior.

Data to AcquireData to Acquire

Car VelocityCar Velocity– Acceleration ComputationAcceleration Computation

Engine SpeedEngine Speed Engine Water TemperatureEngine Water Temperature Oil PressureOil Pressure Suspension travelSuspension travel

– Four SensorsFour Sensors

Functional DescriptionFunctional Description

Aerocomm AC4790-200Aerocomm AC4790-200

900 MHz 900 MHz TransceiversTransceivers

Range of about 1 Range of about 1 mile. (4 miles with mile. (4 miles with external antenna)external antenna)

Aerocomm AC4790-200

Use RS232 Com Port 2 to communicate serially with Transceivers.

TransmitterEMAC Board

RS232

MC-1489Driver

Aerocomm AC4790-200

TTL

Aerocomm AC4790-200

TTL

MC-1488Driver

ReceiverRS232

-15V to +15V

0 to +5V 0 to +5V

-15V to +15V

Aerocomm AC4790-200Aerocomm AC4790-200

Chips must be initialized to same settings.Chips must be initialized to same settings. Use AT Command Mode to Initialize AC4790.Use AT Command Mode to Initialize AC4790. AC4790 responds back to Host when issued AC4790 responds back to Host when issued

a command.a command.

Enter AT Command Mode

Issue Command with no delay between

bytes sent

Is AC4790's response correct?

ERROR

Exit AT Command Mode

Aerocomm AC4790-200Aerocomm AC4790-200

Initializing the AC4790 Initializing the AC4790 for Data Transmissionfor Data Transmission

Aerocomm AC4790-200Aerocomm AC4790-200

AT Command ExampleAT Command Example

Write Read

Aerocomm AC4790-200Aerocomm AC4790-200

Transmitting Data

256 Byte Buffer Set threshold on buffer for

transmission initiation– Set RF Packet Size

Each hop takes 50ms

Additional HardwareAdditional Hardware

One on-board EMAC 80515 One on-board EMAC 80515 Microcontroller Development Board to Microcontroller Development Board to process sensor signals and transmit process sensor signals and transmit them through the RS232 Com Port 2.them through the RS232 Com Port 2.

One additional EMAC 80515 One additional EMAC 80515 Microcontroller Development Board to Microcontroller Development Board to test the receiving end of the system test the receiving end of the system before interfacing the transceiver before interfacing the transceiver directly with a laptop.directly with a laptop.

Equipment ListEquipment List

• (2) EMAC 80515 Microcontroller Development (2) EMAC 80515 Microcontroller Development BoardsBoards

(2) Aerocomm AC4790-20 Transceiver Chips(2) Aerocomm AC4790-20 Transceiver Chips (2) MC1488 and MC1489 Drivers(2) MC1488 and MC1489 Drivers Various Analog Components for Protection Various Analog Components for Protection

CircuitryCircuitry Function GeneratorFunction Generator Digital Multi MeterDigital Multi Meter• Oscilloscope Oscilloscope • LaptopLaptop High Current Power Supply (to run wheel High Current Power Supply (to run wheel

sensor motor)sensor motor)

Software Software RequirementsRequirements Utilize A/D Converter and Utilize A/D Converter and

interrupts to interpret the signals interrupts to interpret the signals from the SAE car.from the SAE car.

Use Com Port 2 to interface the Use Com Port 2 to interface the transceiver with the EMAC board.transceiver with the EMAC board.

Update information as required Update information as required by the Mechanical Engineers.by the Mechanical Engineers.– Different PrioritiesDifferent Priorities

Updating PriorityUpdating Priority

Priority ONEPriority ONE– Car VelocityCar Velocity– Engine SpeedEngine Speed– Suspension TravelSuspension Travel– Lap TimerLap Timer

Priority TWOPriority TWO– Engine Water TemperatureEngine Water Temperature– Oil PressureOil Pressure

Transmitting Flow Transmitting Flow ChartChart

Start

Initialize all necessary timers,

interrupts, registers, etc.

Wait for External, A/D, or Timer

Interrupts

Sensor inputs(RPM,

Temperature, etc)

Store data

Process desired signal from sensor

input

Transmit data

Transmitter Software Flowchart

Set Data Ready Flag

Is Data Ready Flag Set

No

Yes

Clear Data Ready Flag

ReceivingReceiving

Used EMAC board to receive data from Used EMAC board to receive data from the transceiver. the transceiver.

Ideally, the transceiver will be directly Ideally, the transceiver will be directly connected to a laptop through the connected to a laptop through the RS232 port.RS232 port.– MATLAB can provide this functionality.MATLAB can provide this functionality.– Program would store data in some usable Program would store data in some usable

form (i.e. Spreadsheet, notepad file)form (i.e. Spreadsheet, notepad file)– Program would display critical information Program would display critical information

on laptop screen and update as new on laptop screen and update as new information is received.information is received.

Current ProgressCurrent Progress

Completed task of getting two EMAC Completed task of getting two EMAC boards to communicate with each other boards to communicate with each other via RS-232 ports.via RS-232 ports.– Sine wave applied to A/D converter and Sine wave applied to A/D converter and

transmitted out through COM2 port.transmitted out through COM2 port.– Second EMAC board receives converted Second EMAC board receives converted

signal and sends it back to the first EMAC signal and sends it back to the first EMAC board.board.

– When the signal is received by the first When the signal is received by the first EMAC, the transmission is sent out through EMAC, the transmission is sent out through the D/A converter and compared with the the D/A converter and compared with the input signal on an oscilloscope.input signal on an oscilloscope.

Current ProgressCurrent Progress

Current ProgressCurrent Progress

Established serial Established serial communication with communication with AC4790 Transceivers.AC4790 Transceivers.

AT Command Mode AT Command Mode mastered.mastered.

Successfully Successfully initialized both initialized both transceivers.transceivers.

Current ProgressCurrent Progress

•Wirelessly transmitted and received data.

•Successfully sent and received 40 continuous bytes of data in one packet.

•No errors in data

Current ProgressCurrent Progress

Attempted to Attempted to send continuous send continuous streaming datastreaming data– 100Hz Sine 100Hz Sine

WaveWave Buffer filling upBuffer filling up

– Data loss Data loss occurringoccurring

Current Progress

Simulated car signals on transmitting end.

Processed signals and sent out in a packet.– Updated every 0.5s

Future Work

Implement MATLAB Software to display data in real time on off-track computer.– We already have program information

Testing with actual car sensors Design and build casing for inside

the SAE Formula Car– Install hardware on formula car

Questions?Questions?