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
Packaging DesignPackaging Design
• Unibox 171 Battery EnclosureUnibox 171 Battery Enclosure
Packaging DesignPackaging Design
• Glove with Glove with 2 bend2 bend sensors and sensors and 1 pressure1 pressure sensorsensor
Packaging DesignPackaging Design
• 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
Schematic/Theory of OperationSchematic/Theory of Operation
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
Schematic/Theory of OperationSchematic/Theory of Operation
Schematic/Theory of OperationSchematic/Theory of Operation
Recommended by Data Sheet
Schematic/Theory of OperationSchematic/Theory of Operation
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
Schematic/Theory of OperationSchematic/Theory of Operation
1.233V ref
3.3V neededVoltage divider…
Output configuration
Schematic/Theory of OperationSchematic/Theory of Operation
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.
Schematic/Theory of OperationSchematic/Theory of Operation
Schematic/Theory of OperationSchematic/Theory of Operation
Low pass filters10kHz -3dB cutoff
(Recommendedin data sheet)
Schematic/Theory of OperationSchematic/Theory of Operation
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
Schematic/Theory of OperationSchematic/Theory of Operation
Voltage difference between 0lb and 1lb = 3.3*max(R/(10k+R) – R/(35k+R))
~= 1V
R ~= 20k
Schematic/Theory of OperationSchematic/Theory of Operation
Schematic/Theory of OperationSchematic/Theory of Operation
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 Operation
Schematic/Theory of OperationSchematic/Theory of OperationRecommended by data sheet
Schematic/Theory of OperationSchematic/Theory of Operation
Programming/Debugging
Schematic/Theory of OperationSchematic/Theory of Operation
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 Operation
Schematic/Theory of OperationSchematic/Theory of OperationRecommended/required by data sheet
Schematic/Theory of OperationSchematic/Theory of Operation
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