ECE 477 Design Review ECE 477 Design Review Team 5 Team 5 Spring 2009 Spring 2009

Project OverviewProject Overview

• Inertial based character recognition deviceInertial based character recognition device• Battery powered penBattery powered pen• Wall/battery powered base stationWall/battery powered base station• Wireless communication betwixt pen and baseWireless communication betwixt pen and base

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Project-Specific Success CriteriaProject-Specific Success Criteria

• An ability to initiate the drawing of a character.An ability to initiate the drawing of a character.• An ability to match and display characters on An ability to match and display characters on

an LCD screen.an LCD screen.• An ability to monitor battery life and display An ability to monitor battery life and display

status.status.• An ability to interpret data from accelerometers An ability to interpret data from accelerometers

as characters.as characters.• An ability to transmit data wirelessly to a base An ability to transmit data wirelessly to a base

device.device.

Block DiagramBlock Diagram

~3ADXL330(Accelerometer)

PIC18F2320(Microcontroller)

MRF24J40MA(Transceiver)

LTC4150(Fuel Gauge)

7

dsPIC33FJ128GP204(Microcontroller)

MRF24J40MA(Transceiver)

7

HD44780U(LCD)

10

LTC4150(Fuel Gauge)

LTC4054-4.2(Battery Charger)

Pen Base Station

Overall Design ConstraintsOverall Design Constraints

• PenPen– PCB small enough to fit on a penPCB small enough to fit on a pen– Low enough power consumption to run off batteriesLow enough power consumption to run off batteries– Proper peripherals to interface with wireless transceiver Proper peripherals to interface with wireless transceiver

(SPI in master mode) and accelerometers (3 ATD channels)(SPI in master mode) and accelerometers (3 ATD channels)• Base Station Base Station

– Proper peripherals to interface with wireless transceiver Proper peripherals to interface with wireless transceiver (SPI in master mode)(SPI in master mode)

– Enough I/O pins to interface with LCD DisplayEnough I/O pins to interface with LCD Display– Large FLASH memoryLarge FLASH memory

Component Selection ADXL330Component Selection ADXL330

• ‘‘Usable’ packageUsable’ package– LFCSPLFCSP

• Analog signalAnalog signal• 1.8-3.6V1.8-3.6V• 3-Axis3-Axis• 4×4×1.45mm 4×4×1.45mm • Alternative: ADXL 213Alternative: ADXL 213

Component Selection MRF24J40MAComponent Selection MRF24J40MA

• Integration with Integration with microcontrollersmicrocontrollers

• Usable packageUsable package– Surface MountSurface Mount

• All inclusiveAll inclusive• 2.4-3.6V2.4-3.6V• 17.8 mm x 27.9 mm17.8 mm x 27.9 mm• Alternative: Meshnetics Alternative: Meshnetics

MNZB-24-A2 using MNZB-24-A2 using ATmega 1281v MCUATmega 1281v MCU

Component Selection PIC18LF2320Component Selection PIC18LF2320

• 1-SPI; 3-ATD; 1-SPI; 3-ATD; • Software stack for Software stack for

MiWi protocolMiWi protocol• 3.3KB PMemory 3.3KB PMemory

(8192B)(8192B)• 200B Ram (512B)200B Ram (512B)

• 2-5.5V2-5.5V• 0.3 in x 1.4 in0.3 in x 1.4 in• Internal OscillatorInternal Oscillator• Well supportedWell supported

Component Selection dsPIC33FJ128Gp204Component Selection dsPIC33FJ128Gp204

• 1 SPI1 SPI• Software stack for MiWi Software stack for MiWi

protocolprotocol• 3-3.6V3-3.6V• 6 x 6 x 0.9 mm6 x 6 x 0.9 mm• 128KB program memory128KB program memory• Well supportedWell supported• Alternative: Alternative:

dsPIC33FJ64GP306dsPIC33FJ64GP306• 64 GPIO pins64 GPIO pins• 64kB PMemory64kB PMemory

Power Consumption & Battery LifePower Consumption & Battery Life• Pen Pen

– Two Duracell Rechargeable NiMH AA batteries in Two Duracell Rechargeable NiMH AA batteries in seriesseries

– 1800 mAh1800 mAh– 5.5 hours estimated battery life5.5 hours estimated battery life

Component Description

Part #. Current Consumption(mA)

Operating Voltage(V)

Transceiver MRF24J40MA

23 (Tx Mode) 2.4 – 3.6

Microcontroller PIC18LF2320

300 2 – 5.5

Accelerometer ADXL330 0.18 1.8-3.6

Total 323.18

Power Consumption & Battery LifePower Consumption & Battery Life• Base StationBase Station

– Ultralife Li-Ion Rechargeable battery Ultralife Li-Ion Rechargeable battery – 1800 mAh1800 mAh– 8 hours of battery life8 hours of battery life

Component Descriptions

Part #. Current Consumption(mA)

Operating Voltage(V)

Transceiver MRF24J40MA

19 (Rx mode) 2.4 – 3.6

Microcontroller dsPIC33FJ128GP204

200 3 – 3.6

LCD Display LCD16x4BL 4 5

Total 223

Packaging DesignPackaging Design

Pen Power ManagementPen Power Management

Fuel Gauge

Battery Headers 3.3V Boost

Pen Power ManagementPen Power Management

3V (2AA)

3.3V

Possibly remove?

Pen Power ManagementPen Power Management

3V (2AA)

Pen PIC/PeripheralsPen PIC/Peripherals

AccelerometerMicrocontroller

Transmitter

Transmitter Header

ICD2 HeaderAxes Signals

Pen Tip

AccelerometerAccelerometer

MicrocontrollerMicrocontroller

1) VDD2) PGM3) PGC4) PGD5) Reset6) Ground

TransceiverTransceiver

Base Station PowerBase Station Power

4V DC LDO

Fuel Gauge

Battery Charger

3.3V Buck

5V Boost

LDO, Fuel Gauge, Battery ChargerLDO, Fuel Gauge, Battery Charger

5V Boost and 3.3 V Buck5V Boost and 3.3 V Buck

Base Station PIC/PeripheralsBase Station PIC/PeripheralsPIC

LCD Header

Transceiver

PCB Layout – ConstraintsPCB Layout – Constraints

Base station:Base station:- No strict size limitationNo strict size limitation- Separate power management (analog) from Separate power management (analog) from

microcontroller and transceiver (digital) for noise microcontroller and transceiver (digital) for noise controlcontrol

- Transceiver needs to be on the edge of the board Transceiver needs to be on the edge of the board to limit interferenceto limit interference

- 3 power rails: 4 volt regulated, 5 V for LCD, 3.3V 3 power rails: 4 volt regulated, 5 V for LCD, 3.3V for the other digital componentsfor the other digital components

- Size: 1.75” x 4.1”Size: 1.75” x 4.1”

PCB Layout – Base stationPCB Layout – Base station

PCB Layout – Base station (T)PCB Layout – Base station (T)

PCB Layout – Base station (B)PCB Layout – Base station (B)

PCB Layout – Base stationPCB Layout – Base station(ground)(ground)

PCB Layout – Base stationPCB Layout – Base station(4 V)(4 V)

PCB Layout – Base stationPCB Layout – Base station(5 V)(5 V)

PCB Layout – Base stationPCB Layout – Base station(3.3 V)(3.3 V)

PCB Layout – Base stationPCB Layout – Base station (Power management) (Power management)

PCB Layout – Base stationPCB Layout – Base station(dsPIC33)(dsPIC33)

PCB Layout – Base stationPCB Layout – Base station (Transceiver) (Transceiver)

PCB Layout – ConstraintsPCB Layout – Constraints

Portable device (pen):Portable device (pen):- Tight size constraintsTight size constraints- Keep analog traces from accelerometers as short Keep analog traces from accelerometers as short

as possible; accelerometers close to the tip of the as possible; accelerometers close to the tip of the penpen

- Transceiver needs to be on the edge of the board Transceiver needs to be on the edge of the board to limit interference (preferably on top)to limit interference (preferably on top)

- Size: 1.3” x 4.2”Size: 1.3” x 4.2”

PCB Layout – Portable device PCB Layout – Portable device

PCB Layout – Portable device PCB Layout – Portable device

PCB Layout – Portable device PCB Layout – Portable device

PCB– Portable device (ground)PCB– Portable device (ground)

PCB– Portable device (3.3 V)PCB– Portable device (3.3 V)

PCB– Portable device PCB– Portable device (Accelerometers) (Accelerometers)

PCB– Portable device (PIC18)PCB– Portable device (PIC18)

PCB– Portable device PCB– Portable device (Power Management)(Power Management)

PCB– Portable device PCB– Portable device (Transceiver)(Transceiver)

Software Design/Development StatusSoftware Design/Development Status

Pen

Base Station

Project Completion TimelineProject Completion Timeline

Questions / DiscussionQuestions / Discussion