ECE 477 Design Review Team 5  Spring 2009

Project 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 L

Project-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 LCD screen.An ability to match and display characters on an LCD screen. An ability to monitor battery life and display status.An ability to monitor battery life and display status. An ability to interpret data from accelerometers as characters.An ability to interpret data from accelerometers as characters. An ability to transmit data wirelessly to a base device.An ability to transmit data wirelessly to a base device.

Block Diagram ~3 ADXL330 (Accelerometer) ADXL330 (Accelerometer) PIC18F2320 (Microcontroller) PIC18F2320 (Microcontroller) MRF24J40MA (Transceiver) MRF24J40MA (Transceiver) LTC4150 (Fuel Gauge) LTC4150 (Fuel Gauge) 7 dsPIC33FJ128GP204 (Microcontroller) dsPIC33FJ128GP204 (Microcontroller) MRF24J40MA (Transceiver) MRF24J40MA (Transceiver) 7 HD44780U (LCD) HD44780U (LCD) 10 LTC4150 (Fuel Gauge) LTC4150 (Fuel Gauge) LTC (Battery Charger) LTC (Battery Charger) PenBase Station

Overall Design Constraints PenPen –PCB small enough to fit on a pen –Low enough power consumption to run off batteries –Proper peripherals to interface with wireless transceiver (SPI in master mode) and accelerometers (3 ATD channels) Base StationBase Station –Proper peripherals to interface with wireless transceiver (SPI in master mode) –Enough I/O pins to interface with LCD Display –Large FLASH memory

Component Selection ADXL330 ‘Usable’ package‘Usable’ package –LFCSP Analog signalAnalog signal V V 3-Axis3-Axis 4×4×1.45mm4×4×1.45mm Alternative: ADXL 213Alternative: ADXL 213

Component Selection MRF24J40MA Integration with microcontrollersIntegration with microcontrollers Usable packageUsable package –Surface Mount All inclusiveAll inclusive V V 17.8 mm x 27.9 mm17.8 mm x 27.9 mm Alternative: Meshnetics MNZB-24-A2 using ATmega 1281v MCUAlternative: Meshnetics MNZB-24-A2 using ATmega 1281v MCU

Component Selection PIC18LF SPI; 3-ATD;1-SPI; 3-ATD; Software stack for MiWi protocolSoftware stack for MiWi protocol 3.3KB PMemory (8192B)3.3KB PMemory (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 dsPIC33FJ128Gp204 1 SPI1 SPI Software stack for MiWi protocolSoftware stack for MiWi protocol 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: dsPIC33FJ64GP306Alternative: dsPIC33FJ64GP GPIO pins64 GPIO pins 64kB PMemory64kB PMemory

Power Consumption & Battery Life PenPen –Two Duracell Rechargeable NiMH AA batteries in series –1800 mAh –5.5 hours estimated battery life Component Description Part #.Current Consumption (mA) Operating Voltage (V) TransceiverMRF24J40 MA 23 (Tx Mode)2.4 – 3.6 MicrocontrollerPIC18LF – 5.5 AccelerometerADXL Total323.18

Power Consumption & Battery Life Base StationBase Station –Ultralife Li-Ion Rechargeable battery –1800 mAh –8 hours of battery life Component Descriptions Part #.Current Consumption (mA) Operating Voltage (V) TransceiverMRF24J40 MA 19 (Rx mode)2.4 – 3.6 MicrocontrollerdsPIC33FJ1 28GP – 3.6 LCD DisplayLCD16x4BL45 Total223

Packaging Design

Pen Power Management Fuel Gauge Battery Headers 3.3V Boost

Pen Power Management 3V (2AA) 3.3V Possibly remove?

Pen Power Management 3V (2AA)

Pen PIC/Peripherals Accelerometer Microcontroller Transmitter Transmitter Header ICD2 Header Axes Signals Pen Tip

Accelerometer

Microcontroller

Transceiver

Base Station Power 4V DC LDO Fuel Gauge Battery Charger 3.3V Buck 5V Boost

LDO, Fuel Gauge, Battery Charger

5V Boost and 3.3 V Buck

Base Station PIC/Peripherals PIC LCD Header Transceiver

PCB Layout – Constraints Base station: -No strict size limitation -Separate power management (analog) from microcontroller and transceiver (digital) for noise control -Transceiver needs to be on the edge of the board to limit interference -3 power rails: 4 volt regulated, 5 V for LCD, 3.3V for the other digital components -Size: 1.75” x 4.1”

PCB Layout – Base station

PCB Layout – Base station (T)

PCB Layout – Base station (B)

PCB Layout – Base station (ground)

PCB Layout – Base station (4 V)

PCB Layout – Base station (5 V)

PCB Layout – Base station (3.3 V)

PCB Layout – Base station (Power management)

PCB Layout – Base station (dsPIC33)

PCB Layout – Base station (Transceiver)

PCB Layout – Constraints Portable device (pen): -Tight size constraints -Keep analog traces from accelerometers as short as possible; accelerometers close to the tip of the pen -Transceiver needs to be on the edge of the board to limit interference (preferably on top) -Size: 1.3” x 4.2”

PCB Layout – Portable device

PCB– Portable device (ground)

PCB– Portable device (3.3 V)

PCB– Portable device (Accelerometers)

PCB– Portable device (PIC18)

PCB– Portable device (Power Management)

PCB– Portable device (Transceiver)

Software Design/Development Status Pen Base Station

Project Completion Timeline

Questions / Discussion