ECE 477 Design Review Team 7 Spring 2006. Outline Project overviewProject overview Project-specific...

ECE 477 Design Review ECE 477 Design Review Team 7 Team 7 Spring 2006 Spring 2006

OutlineOutline• Project overview Project overview • Project-specific success criteriaProject-specific success criteria• Block diagramBlock diagram• Component selection rationaleComponent selection rationale• Packaging designPackaging design• Schematic and theory of operationSchematic and theory of operation• PCB layoutPCB layout• Software design/development statusSoftware design/development status• Project completion timelineProject completion timeline• Questions / discussionQuestions / discussion

Project OverviewProject Overview• Alternative HID that can replace the mouse.Alternative HID that can replace the mouse.• Package the HID into a wearable glove.Package the HID into a wearable glove.• Use feedback from bend sensors and/or Use feedback from bend sensors and/or

pressure sensors to simulate mouse clicks.pressure sensors to simulate mouse clicks.• Use two three-axis accelerometers to Use two three-axis accelerometers to

simulate mouse movement.simulate mouse movement.• Two components: glove and base station.Two components: glove and base station.• Glove communicates to base station via RF.Glove communicates to base station via RF.• Base station decodes RF data into USB Base station decodes RF data into USB

signals and sends them to PC.signals and sends them to PC.

Project-Specific Success CriteriaProject-Specific Success Criteria

• An ability to detect “finger taps” based on pressure An ability to detect “finger taps” based on pressure sensor and bend sensor data.sensor and bend sensor data.

• An ability to detect hand movements with an An ability to detect hand movements with an accelerometer.accelerometer.

• An ability to detect wrist twisting with an additional An ability to detect wrist twisting with an additional accelerometer.accelerometer.

• An ability to wirelessly transmit encoded An ability to wirelessly transmit encoded finger/wrist/hand movements to base station.finger/wrist/hand movements to base station.

• An ability to translate encoded finger/wrist/hand An ability to translate encoded finger/wrist/hand movements into “Windows mouse” format (using movements into “Windows mouse” format (using USB protocol”USB protocol”

Block DiagramBlock Diagram

RF TransceiverMicrocontroller

Bend Sensorson fingers

2

Accelerometers3

3

Pressure Sensoron Thumb

DC-DC Converter

3.0 V2 AA batt.

3.3VBoost

Glove

To Base Station

Settings

ShiftRegister

A/D

Block DiagramBlock Diagram

RF Transceiver Microcontroller

3.3 V reg

PCUSB

Base StationRFFrom Glove

LeveltranslatorData

Component Selection RationaleComponent Selection Rationale

• Glove uC - Freescale MC9S08GT16Glove uC - Freescale MC9S08GT16– Packaging availability = QFPPackaging availability = QFP

• Cypress CY7C60223 = DIPCypress CY7C60223 = DIP– Standby current = 25 nAStandby current = 25 nA

• Cypress CY7C60223 = 10 uACypress CY7C60223 = 10 uA– 6.5 mA @ 16 Mhz 6.5 mA @ 16 Mhz

• Cypress CY7C60223 = 11 mA @ 16 MhzCypress CY7C60223 = 11 mA @ 16 Mhz– 8 channel ATD8 channel ATD

• Cypress CY7C60223 = no ATDCypress CY7C60223 = no ATD

Component Selection RationaleComponent Selection Rationale• Base Station uC - Freescale MC908JB16FAEBase Station uC - Freescale MC908JB16FAE

– Packaging availability = QFPPackaging availability = QFP• Cypress CY7C63823-PXC = DIPCypress CY7C63823-PXC = DIP

– Keyboard interruptsKeyboard interrupts– DocumentationDocumentation– Keeping it in the familyKeeping it in the family

Component Selection RationaleComponent Selection Rationale• RF Module – Spark Fun RF-MiRFRF Module – Spark Fun RF-MiRF

– Range = 50 ft (125 ft line of sight)Range = 50 ft (125 ft line of sight)• Freescale xx3316 = 6 ftFreescale xx3316 = 6 ft• Cypress CYWM6934 = 30 ftCypress CYWM6934 = 30 ft

– Availability = immediateAvailability = immediate• Cypress CYWM6934 still not receivedCypress CYWM6934 still not received

Component Selection RationaleComponent Selection Rationale• RF Module – Spark Fun RF-MiRFRF Module – Spark Fun RF-MiRF

– ShockBurst TechnologyShockBurst Technology

Component Selection RationaleComponent Selection Rationale• Accelerometer – Freescale MMA7260QAccelerometer – Freescale MMA7260Q

– Current consumption = 500 uACurrent consumption = 500 uA• STMicroelectronics E-LIS3L02AS4 = 1.5mASTMicroelectronics E-LIS3L02AS4 = 1.5mA

– Available packaging = QFPAvailable packaging = QFP• STMicroelectronics E-LIS3L02AS4 = SOICSTMicroelectronics E-LIS3L02AS4 = SOIC

– Cost = freeCost = free• STMicroelectronics = $50 (5 X $10)STMicroelectronics = $50 (5 X $10)

Component Selection RationaleComponent Selection Rationale• Step-Up DC-DC Converter – Maxim MAX1705Step-Up DC-DC Converter – Maxim MAX1705

– 96% efficiency96% efficiency• Need 95% for power consumption Need 95% for power consumption

predictions based on case study to holdpredictions based on case study to hold– Low battery detectorLow battery detector– Cost = freeCost = free

Packaging DesignPackaging Design

• Unibox 171 Battery EnclosureUnibox 171 Battery Enclosure– 4.37” X 3.25” X 1.50” (L X W X H external)4.37” X 3.25” X 1.50” (L X W X H external)– Able to hold two 1” high accelerometer Able to hold two 1” high accelerometer

modulesmodules– On the top of the enclosureOn the top of the enclosure

• Low battery LEDLow battery LED• On/Off switch, reset buttonOn/Off switch, reset button• Axis switchAxis switch

– Velcro strap to secure to forearmVelcro strap to secure to forearm


• Unibox 171 Battery EnclosureUnibox 171 Battery Enclosure


• Glove with Glove with 2 bend2 bend sensors and sensors and 1 pressure1 pressure sensorsensor


• Immersion CyberGlove IIImmersion CyberGlove II

Schematic/Theory of OperationSchematic/Theory of Operation

The Glove schematic is laid out in a modular The Glove schematic is laid out in a modular structure, with each module containing a key structure, with each module containing a key component of the overall circuit:component of the overall circuit:

Mobile StationMobile Station• Power SupplyPower Supply• Sensors/User InterfaceSensors/User Interface• AccelerometersAccelerometers• MicrocontrollerMicrocontroller

Base StationBase Station• MicrocontrollerMicrocontroller


Power SupplyPower Supply• 2 AA Batteries (NiCd/NiMH) (3.0V supply) Input2 AA Batteries (NiCd/NiMH) (3.0V supply) Input• DC-DC Boost Converter (MAX1705)DC-DC Boost Converter (MAX1705)

– Outputs 3.3VOutputs 3.3V– Supplies up to 850mASupplies up to 850mA

• ““Low Battery” detector when battery voltage reaches Low Battery” detector when battery voltage reaches 1.5V1.5V


Recommended by Data Sheet


1.5V LEDWithout series resistance 1mA sink

Battery voltage drops to 1.5V, LBO goes to low state

Low Battery Detector

Schematic/Theory of OperationSchematic/Theory of OperationLow Battery Detector

1.25V

1.5V

Voltage divider…

Route from + terminal to - terminal


1.233V ref

3.3V neededVoltage divider…

Output configuration


3-Axis Accelerometers3-Axis Accelerometers• Analog outputs representing acceleration along 3 Analog outputs representing acceleration along 3

orthogonal axes.orthogonal axes.– Filtered by 1Filtered by 1stst order low pass filter to reduce high order low pass filter to reduce high

frequency noise. (10kHz -3dB cutoff)frequency noise. (10kHz -3dB cutoff)• Digital inputs select sensitivity and sleep mode.Digital inputs select sensitivity and sleep mode.


Low pass filters10kHz -3dB cutoff

(Recommendedin data sheet)


Sensors/InterfaceSensors/Interface• Bend Sensors – Click OperationBend Sensors – Click Operation

– 10kOhm in rest state, ~35kOhm MAX 1lb applied10kOhm in rest state, ~35kOhm MAX 1lb applied• Pressure Sensor – Click EnablePressure Sensor – Click Enable

– Filtered by 1Filtered by 1stst order low pass filter to reduce high order low pass filter to reduce high frequency noise. (10kHz -3dB cutoff)frequency noise. (10kHz -3dB cutoff)

• On/Off switch – disconnects batteryOn/Off switch – disconnects battery• Axes switchAxes switch

– Move mouse up-down-left-right, or forward-backward-Move mouse up-down-left-right, or forward-backward-left-rightleft-right


Voltage difference between 0lb and 1lb = 3.3*max(R/(10k+R) – R/(35k+R))

~= 1V

R ~= 20k


Microcontroller (Mobile)Microcontroller (Mobile)• 500kHz Clock Frequency500kHz Clock Frequency• Sensors/AccelerometersSensors/Accelerometers

– A/D moduleA/D module• RF ModuleRF Module

– I/O input pins/shift registerI/O input pins/shift register• Programming/DebuggingProgramming/Debugging

– 6 pin header for programming6 pin header for programming– Switch on reset pinSwitch on reset pin– IRQ brought out to a headerIRQ brought out to a header

Schematic/Theory of OperationSchematic/Theory of OperationRecommended by data sheet


Programming/Debugging


Microcontroller (Base)Microcontroller (Base)• 6MHz Bus Speed, 5.0V USB power supply6MHz Bus Speed, 5.0V USB power supply• RF moduleRF module

– ConnectedConnected• RF ModuleRF Module

– Powered by on-board 3.3V regulatorPowered by on-board 3.3V regulator– I/O input pins/shift register (5.0V to 3.3V bidirectional I/O input pins/shift register (5.0V to 3.3V bidirectional

level translator)level translator)– ““Data Received” pin connected to IRQData Received” pin connected to IRQ

• Programming/DebuggingProgramming/Debugging– USB, switch for reset pinUSB, switch for reset pin

Schematic/Theory of OperationSchematic/Theory of OperationRecommended/required by data sheet


5.0V to 3.3VBidirectional Level Translator

Translator

PCB Layout OutlinePCB Layout Outline

• Packaging Constraints and InterfacingPackaging Constraints and Interfacing• EMI ReductionEMI Reduction

– Power SystemPower System– CapacitorsCapacitors– Component PlacementComponent Placement

• RFRF• SensorsSensors• Clock CircuitryClock Circuitry

– TracesTraces

UpdateOld

PCB LayoutPCB Layout

PCB PackagingPCB Packaging

• Not too bulkyNot too bulky• Fit on wristFit on wrist• All Surface Mount PartsAll Surface Mount Parts

– Mostly 1206Mostly 1206• 100 mil spaced headers100 mil spaced headers• Currently 3.725 x 2.285Currently 3.725 x 2.285

PCB InterfacingPCB Interfacing

• SensorsSensors• RFRF• AccelerometersAccelerometers• DebugDebug• PowerPower

RF Modules

BDM

AXIS

Accelerometers

LED

On/Off

Battery

Reset

Reset

USB

Sensors

Base Station

Glove

IRQ

PCB Power System GlovePCB Power System Glove• Wide Power/Ground Wide Power/Ground

RailsRails• Stable GroundStable Ground• Copper PourCopper Pour

TopPower

BottomGround

PCB Power System BasePCB Power System Base• Wide Power/GroundWide Power/Ground• Multipoint GroundMultipoint Ground• Copper PourCopper Pour

BottomPower

TopGround

PCB CapacitorsPCB Capacitors• Decoupling CapsDecoupling Caps• Bypass CapsBypass Caps• RecommendedRecommended

PCB ComponentPCB ComponentPlacementPlacement

• RFRF• A/DA/D• Clock CircuitryClock Circuitry

Clock CircuitryRF Modules

A/D Inputs

PCB TracesPCB Traces

• Trace width – 12 milTrace width – 12 mil• Power/Ground – 20-60 milPower/Ground – 20-60 mil• Avoided 90 Degree AnglesAvoided 90 Degree Angles• Minimized amount of viasMinimized amount of vias

– 28 in updated glove28 in updated glove– 22 in updated base station22 in updated base station

60 mil Trace

Avoid!

Software Design/Development Software Design/Development StatusStatus

TransmitterTransmitter– Main routineMain routine

• Check sensor data place in FIFO bufferCheck sensor data place in FIFO buffer

• Check accelerometer data place in FIFOCheck accelerometer data place in FIFO

• Do power managementDo power management

– RF timer interruptRF timer interrupt

• Check FIFO and send data.Check FIFO and send data.

ReceiverReceiver– Main routineMain routine

• Checks buffer and converts data to USB format to be sent to Checks buffer and converts data to USB format to be sent to host.host.

– Timer interrupt. Timer interrupt.

• Catch RF data and place in buffer.Catch RF data and place in buffer.

– USB interrupt routineUSB interrupt routine

Project Completion TimelineProject Completion Timeline

Final Documentation

Packaging

Testing

Software

Building

4/234/164/94/23/263/193/123/52/27Week

Questions / DiscussionQuestions / Discussion

ECE 477 Design Review Team 7 Spring 2006. Outline Project overviewProject overview Project-specific...

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