ECE 477 Design Review Team 7  Spring 2006

Outline Project overviewProject 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 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 pressure sensors to simulate mouse clicks.Use feedback from bend sensors and/or pressure sensors to simulate mouse clicks. Use two three-axis accelerometers to simulate mouse movement.Use two three-axis accelerometers to 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 signals and sends them to PC.Base station decodes RF data into USB signals and sends them to PC.

Project-Specific Success Criteria An ability to detect “finger taps” based on pressure sensor and bend sensor data.An ability to detect “finger taps” based on pressure sensor and bend sensor data. An ability to detect hand movements with an accelerometer.An ability to detect hand movements with an accelerometer. An ability to detect wrist twisting with an additional accelerometer.An ability to detect wrist twisting with an additional accelerometer. An ability to wirelessly transmit encoded finger/wrist/hand movements to base station.An ability to wirelessly transmit encoded finger/wrist/hand movements to base station. An ability to translate encoded finger/wrist/hand movements into “Windows mouse” format (using USB protocol”An ability to translate encoded finger/wrist/hand movements into “Windows mouse” format (using USB protocol”

Block Diagram

Component Selection Rationale Glove uC - Freescale MC9S08GT16Glove uC - Freescale MC9S08GT16 –Packaging availability = QFP Cypress CY7C60223 = DIPCypress CY7C60223 = DIP –Standby current = 25 nA Cypress CY7C60223 = 10 uACypress CY7C60223 = 10 uA – Mhz Cypress CY7C60223 = MhzCypress CY7C60223 = Mhz –8 channel ATD Cypress CY7C60223 = no ATDCypress CY7C60223 = no ATD

Component Selection Rationale Base Station uC - Freescale MC908JB16FAEBase Station uC - Freescale MC908JB16FAE –Packaging availability = QFP Cypress CY7C63823-PXC = DIPCypress CY7C63823-PXC = DIP –Keyboard interrupts –Documentation –Keeping it in the family

Component Selection Rationale RF Module – Spark Fun RF-MiRFRF Module – Spark Fun RF-MiRF –Range = 50 ft (125 ft line of sight) Freescale xx3316 = 6 ftFreescale xx3316 = 6 ft Cypress CYWM6934 = 30 ftCypress CYWM6934 = 30 ft –Availability = immediate Cypress CYWM6934 still not receivedCypress CYWM6934 still not received

Component Selection Rationale RF Module – Spark Fun RF-MiRFRF Module – Spark Fun RF-MiRF –ShockBurst Technology

Component Selection Rationale Accelerometer – Freescale MMA7260QAccelerometer – Freescale MMA7260Q –Current consumption = 500 uA STMicroelectronics E-LIS3L02AS4 = 1.5mASTMicroelectronics E-LIS3L02AS4 = 1.5mA –Available packaging = QFP STMicroelectronics E-LIS3L02AS4 = SOICSTMicroelectronics E-LIS3L02AS4 = SOIC –Cost = free STMicroelectronics = $50 (5 X $10)STMicroelectronics = $50 (5 X $10)

Component Selection Rationale Step-Up DC-DC Converter – Maxim MAX1705Step-Up DC-DC Converter – Maxim MAX1705 –96% efficiency Need 95% for power consumption predictions based on case study to holdNeed 95% for power consumption predictions based on case study to hold –Low battery detector –Cost = free

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

Packaging Design Unibox 171 Battery EnclosureUnibox 171 Battery Enclosure

Packaging Design Glove with 2 bend sensors and 1 pressure sensorGlove with 2 bend sensors and 1 pressure sensor

Packaging Design Immersion CyberGlove IIImmersion CyberGlove II

Schematic/Theory of Operation The Glove schematic is laid out in a modular structure, with each module containing a key component of the overall circuit: The Glove schematic is laid out in a modular structure, with each module containing a key component of the overall circuit: Mobile Station Power SupplyPower Supply Sensors/User InterfaceSensors/User Interface AccelerometersAccelerometers MicrocontrollerMicrocontroller Base Station MicrocontrollerMicrocontroller

Schematic/Theory of Operation Power 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 3.3V –Supplies up to 850mA “Low Battery” detector when battery voltage reaches 1.5V“Low Battery” detector when battery voltage reaches 1.5V

Schematic/Theory of Operation

Recommended by Data Sheet

Schematic/Theory of Operation 1.5V LED Without series resistance 1mA sink Battery voltage drops to 1.5V, LBO goes to low state Low Battery Detector

Schematic/Theory of Operation Low Battery Detector 1.25V 1.5V Voltage divider… Route from + terminal to - terminal

Schematic/Theory of Operation 1.233V ref 3.3V needed Voltage divider… Output configuration

Schematic/Theory of Operation 3-Axis Accelerometers Analog outputs representing acceleration along 3 orthogonal axes.Analog outputs representing acceleration along 3 orthogonal axes. –Filtered by 1 st order low pass filter to reduce high frequency noise. (10kHz -3dB cutoff) Digital inputs select sensitivity and sleep mode.Digital inputs select sensitivity and sleep mode.

Schematic/Theory of Operation

Low pass filters 10kHz -3dB cutoff (Recommended in data sheet)

Schematic/Theory of Operation Sensors/Interface Bend Sensors – Click OperationBend Sensors – Click Operation –10kOhm in rest state, ~35kOhm MAX 1lb applied Pressure Sensor – Click EnablePressure Sensor – Click Enable –Filtered by 1 st order low pass filter to reduce high 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- left-right

Schematic/Theory of Operation Voltage difference between 0lb and 1lb = 3.3*max(R/(10k+R) – R/(35k+R)) ~= 1V R ~= 20k

Schematic/Theory of Operation

Microcontroller (Mobile) 500kHz Clock Frequency500kHz Clock Frequency Sensors/AccelerometersSensors/Accelerometers –A/D module RF ModuleRF Module –I/O input pins/shift register Programming/DebuggingProgramming/Debugging –6 pin header for programming –Switch on reset pin –IRQ brought out to a header

Schematic/Theory of Operation

Recommended by data sheet

Schematic/Theory of Operation Programming /Debugging

Schematic/Theory of Operation Microcontroller (Base) 6MHz Bus Speed, 5.0V USB power supply6MHz Bus Speed, 5.0V USB power supply RF moduleRF module –Connected RF ModuleRF Module –Powered by on-board 3.3V regulator –I/O input pins/shift register (5.0V to 3.3V bidirectional level translator) –“Data Received” pin connected to IRQ Programming/DebuggingProgramming/Debugging –USB, switch for reset pin

Schematic/Theory of Operation

Recommended/required by data sheet

Schematic/Theory of Operation 5.0V to 3.3V Bidirectional Level Translator Translator

PCB Layout Outline Packaging Constraints and InterfacingPackaging Constraints and Interfacing EMI ReductionEMI Reduction –Power System –Capacitors –Component Placement RFRF SensorsSensors Clock CircuitryClock Circuitry –Traces

UpdateOld PCB Layout

PCB Packaging Not too bulkyNot too bulky Fit on wristFit on wrist All Surface Mount PartsAll Surface Mount Parts –Mostly mil spaced headers100 mil spaced headers Currently x 2.285Currently x 2.285

PCB Interfacing SensorsSensors RFRF AccelerometersAccelerometers DebugDebug PowerPower RF Modules BDM AXIS Accelerometers LED On/Off Battery Reset USB Sensors Base Station Glove IRQ

PCB Power System Glove Wide Power/Ground RailsWide Power/Ground Rails Stable GroundStable Ground Copper PourCopper Pour Top Power Bottom Ground

PCB Power System Base Wide Power/GroundWide Power/Ground Multipoint GroundMultipoint Ground Copper PourCopper Pour Bottom Power Top Ground

PCB Capacitors Decoupling CapsDecoupling Caps Bypass CapsBypass Caps RecommendedRecommended

PCB Component Placement RFRF A/DA/D Clock CircuitryClock Circuitry Clock Circuitry RF Modules A/D Inputs

PCB Traces Trace width – 12 milTrace width – 12 mil Power/Ground – milPower/Ground – mil Avoided 90 Degree AnglesAvoided 90 Degree Angles Minimized amount of viasMinimized amount of vias –28 in updated glove –22 in updated base station 60 mil Trace Avoid!

Software Design/Development Status Transmitter –Main 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 interrupt Check FIFO and send data.Check FIFO and send data.Receiver –Main routine Checks buffer and converts data to USB format to be sent to host.Checks buffer and converts data to USB format to be sent to host. –Timer interrupt. Catch RF data and place in buffer.Catch RF data and place in buffer. –USB interrupt routine

Project Completion Timeline Final Documentation Packaging Testing Software Building 4/234/164/94/23/263/193/123/52/27Week

Questions / Discussion