gps & sensor telemetry formula sae ryan langley 2104584 hpv sensor suite thomas cross 2107294

GPS & Sensor Telemetry

Formula SAE

Ryan Langley

2104584

HPV Sensor Suite

Thomas Cross

2107294

HPV Super Series

• Human Powered Vehicle

• Multiple riders per vehicle

• Endurance races

• Manual lap timing

Project Aims

• Sensor suite onboard vehicle

• Location, speed and lap times

• Data logging

• Display data to pit crew

Pit Module•Graphical User Interface

•View real-time data

•Log/display lap times

•Data communications

Vehicle Module•GPS + Accelerometer

•Speed display

•Data logging

•Data communications

GUI

Firmware

Hardware

RF Module

Reverse Polarity & Overvoltage Protection

Switched-Mode Power Supply (5V)

Linear Regulator(3.3V)

Liquid Crystal Display

Microcontroller

SD Card

Microcontroller

I2CUART

UART I2C SPI

Input Power

GPS Module Accelerometer

Circuit Protection

• Reverse polarity protection

• Overvoltage protection

• Transient suppression

RF Module





Microcontroller

SD Card

Microcontroller

I2CUART

UART I2C SPI

Input Power


Power Supply

• 3.3V and 5V rails– Linear regulator for each rail – 5V SMPS powering 3.3V linear regulator– SMPS for each rail– 3.3V @ 0.1A– 5V @ 0.9A

Ploss (W) Efficiency Cost($AU)

2 x Linear 7.17 40.3% $3.30

1 x SMPS1 x Linear

1.42 77.3% $9.41

2 x SMPS 1.21 80% $15.52

RF Module





Microcontroller

SD Card

Microcontroller

I2CUART

UART I2C SPI

Input Power


Inputs

• GPS Module– Updates at 10Hz– UART - NMEA Data and checksum– 2.5m location accuracy

• Accelerometer– MMA8451Q– 3-Axis– I2C

RF Module





Microcontroller

SD Card

Microcontroller

I2CUART

UART I2C SPI

Input Power


Outputs

• RF Module - RFD900– UART– 40km LOS

• LCD– I2C– Displays data to rider

• SD Card– SPI– microSD

RF Module





Microcontroller

SD Card

Microcontroller

I2CUART

UART I2C SPI

Input Power


Microcontroller

• 2 x UART - GPS & RF Module

• 1 x SPI - SD Card (SPI Mode)

• 1 x I2C - Accelerometer, LCD

• PIC18F46K22– 2 x UART, 2 x SPI/I2C– 64KB Program Memory– 64MHz oscillator

AccelerometerSD Card

GPS

Protection Circuitry

5V SMPS

3.3V LinearRegulator

Programming Header

GUI

Firmware

Hardware

Formula SAE

• Design & build race car

• Students of all disciplines

• Annual competition

• Flinders’ first year

GPS Telemetry Project

• Basis for sensor addition

• Build car and driver feedback

• Improve performance of team

Firmware Goals

• Configure sensors

• Read in, send and process data

• Log data

• Handle errors

• All in real time – or close to

GPS

• Configure UART peripheral

• Configure GPS module

• Receive NMEA data

• Process & Send data

Configure UART

• 1 start – 8 data – 1 stop – no parity

• 115,200 baud

• Interrupt based

• Ring buffer

TAIL

HEAD

$ G P R M C

Configure UART

GPS





Configure GPS Module

• Send only GPRMC and GPGSA– Lat & long– Date & time– Speed, heading– Precision

• Configure baud to 115,200

• Send data at 10 Hz

GPS





Receive NMEA Data

$

\n

GPS_msg_flag

N

YY

N

Receive ISR

GPS





Process & Send Data

• Pull msg from RX buffer

M C … \n$ G P R 0

N

NY

Y

Accelerometer

• Configure I2C peripheral

• Configure Accelerometer module

• Obtain data

Configure I2C

• 400 kHz speed

• Set as Master device

• Generic code

Accelerometer



• Obtain data

Configure Accelerometer

• Read latest data (not FIFO)

• 8G, 4G, or 2G mode

• 8-bit resolution

Accelerometer



• Obtain data

Obtain data

• Read the values at 10 Hz

• Use ‘get’ functions to access

X, Y, and Z values.

The Main Loop

The Results

The Results

ACC IN

RFD OUT

GPS IN

Data Logging

• Easy to use

• Windows compatible file system

• Different files for GPS and ACC data

SD_Card.hSD_Card.c

Data Logging

SPI.hSPI.c

FatFsFiles

Main Loop

diskio.hdiskio.c

SD_Card.hSD_Card.c

diskio.hdiskio.c

SPI.hSPI.c

FatFsFiles

Main Loop

SD Card

• Provides high-level logging functions– Create/open files– Log ACC data– Log GPS data– Save files

SD_Card.hSD_Card.c

SPI.hSPI.c

FatFsFiles

diskio.hdiskio.c

Main Loop

FatFs

• Generic FAT File System Module

• Designed for embedded systems

• 3rd party open source

• Platform independent

SD_Card.hSD_Card.c

SPI.hSPI.c

FatFsFiles

diskio.hdiskio.c

Main Loop

Disk IO

• Provides low-level disk IO functions– Initialize– Read– Write– Disk Status

SD_Card.hSD_Card.c

SPI.hSPI.c

FatFsFiles

diskio.hdiskio.c

Main Loop

SPI

• Portable SPI peripheral code

• Various initialization options

• Byte transmit, receive and exchange

Logging Result

GUI

Firmware

Hardware

Yes

No

Get Message TypeValid Message Header?No

Yes

New Message Received?

Yes

Valid Message?

Extract Message Data

No

Update Lap/Race Timer

10 Hz

Plot GPS Location Display Acceleration

Lap Detected?

Log Lap Time

Yes

Re

se

t

Receiving Data

• Scan until new message is received

• Check for valid header e.g. “$GPRMC…”

• Check for correct length and checksum

• Extract message data– Lat & long– Date & time– Speed, heading

Update GUI

• Update lap/race counter every 0.1s

• Plot most recent GPS location

• Display accelerometer data

• Display heading/speed

Lap Detection

• Check if travel line crosses finish line

• Log lap time and display on graph/table

• Reset lap timer

Summary

• Designed generic hardware

• Data processing and transmission

• Display real-time data on user interface

• Autonomously log lap times

gps & sensor telemetry formula sae ryan langley 2104584 hpv sensor suite thomas cross 2107294

Documents

vlinear regulator3

lcdpic18f46k222 x uart

smps1 x linear1

au2 x linear7

dataconfigure gps modulesend

hzuart nmea data

sensor additionbuild

dataconfigure uart1