PowerPoint Presentation

Group 10Angelo BiaggiTrent GallagherRyan PearceLomar St.Louis

SmartChairSummaryThe SmartChair is a safety and security-enhanced wheelchair.It takes a typical, everyday manual wheelchair and turns it into a transportation device that takes advantage of modern technology.Targeted primarily towards elderly users.Can be locked to be left unattended, only unlocked by a unique RFID key.Has a GPS tracker which uses GSM so data can be received in most places around the world.Pressure pads detect when the user is getting in or out of the chair, and will automatically lock the wheels.LCD screen displays basic information to the user.RFID Technology Comparison

Cost is referring to the tags, however for a single receiver/scanner combo, LF was much cheaper.RFID Receiver Overview

4 PinsVCC (+5V)GND/ENABLE (input)SOUT (output)

Small size, efficientAllows for convenient placement on the wheelchairLow power use when scanning, and almost-zero power use when not scanning.RFID Receiver Overview/ENABLE Flag (input)HIGH = Scanner is off, power consumption is down.LOW = Scanning actively for keys and passing them out serially to the SOUT lineSOUTData is transmitted at 5V over serial communication.RFID Receiver OverviewSOUT (continued)Transfer protocol

CommunicationSerialData bits8Stop bits1ParityNoBit OrderLeast significant bit firstTransfer speed2400 bpsSignal5V TTL-level, non-inverted asynchronous serial

RFID Receiver OverviewSOUT (continued)12 bytes transferred from a key read

Middle 10 bytes are ASCII charactersStart byte is 0x0A , NewLineEnd byte is 0x0D, Carriage Return

RFID Receiver OverviewLEDAlong with the RFID lock/unlock system will be a simple LED that changes colors based on the current state:

LED ColorMeaningOccurs WhenGREENIdle state - Not searching/ENABLE port is either HIGH or disconnectedREDActively searching for RFID key/ENABLE is LOWBlankNo powerVCC is low or disconnected

RFID Receiver OverviewDC Characteristics of RFID Receiver

RFID Receiver OverviewMaximum Ratings of RFID ReceiverThey are well within the conditions of most human-populated areas of the world

RFID Tag OverviewPassive Key used with Low Frequency RFID technology.ReliableHas no battery requirement, should function well beyond any users needs.Works by harvesting the energy from the receiver transmission, modulating it, and transmitting back the unique ASCII code of the key.RFID Software OverviewReads tags from the RFID receiver and compares them to a list of known/accepted tags.

Unattended Mode (Device Locked)An unattended mode button is pushed to lock the device.

Before the Main/Scan loop occursThe motor is sent a signal to lock the wheelsThe RFID receiver is set to active (by setting /ENABLE to LOW), which causes the LED to turn redThe LED being red will be a clear indicator that the wheelchair is locked

Main Scanning LoopWhen a 12-byte set is registered that has the correct start and end bytes, the middle 10 bytes are compared against each valid key listed in the EEPROM.This continues until a match is found, at which point the device unlocks.

Unlock/ResetSpeaker sound (may be removed)LED turns green to notify of unlocked stateWheels are unlockedPressure Pad logic is reactivated

FlexiForce A201 & A401 SensorsSpecificationsA201A401Thickness0.208 mm0.208 mmLength197 mm56.8 mmWidth14 mm31.8 mmSensing Area9.53 mm diameter25.4 mm diameterConnector3-pin Male Square Pin2-pin male square pinSubstratePolyesterPolyesterPin Spacing2.54 mm2.54 mmLinearity Error< 3%< 3%Repeatability< 2.5% of full scale< 2.5% of full scaleHysteresis< 4.5% of full scale< 4.5% of full scaleDrift< 5% per logarithmic time scale< 5% per logarithmic time scaleResponse Time< 5 microseconds< 5 microsecondsOperating Temperatures-40C 60C-40F 140FForce Ranges4.4 N, 110 N, 440 N0 1 lb, 0 25 lb, 0 100 lbTemperature SensitivityOutput variance of 0.2% per degreeOutput variance of 0.2% per degreeHow to Adjust Force Range

Piston Driven ActuatorDisadvantageImmediate harsh braking

If for any reason at least one of the piston driven actuators does not fire correctly and on time, it would result in the safety enhanced wheelchair moving backwards or rotating around while the person using the safety enhanced wheelchair is trying to get out of it. 18Locking Mechanism

SolenoidSpecificationsTypeBox FrameStroke Range1/8 in to 1 inPull Force Range20 oz to 130 ozWidth1.5625 inDepth1.625 inLength2.1875 inCoil Volts12 DCSeated Amps2.6 ASeated Watts32.3 WCoil Resistance4.68 Price$54.70Coil InsulationClass 105TerminalsSolder LugDuty CycleIntermittentMaterials of ConstructionSteelStandardsUL, RoHSMountng Holes8-32 UNC-2B20N-Channel MosfetSpecificationsModelFQP30N06LDrain-Source Voltage60 VDrain-Source Current32 AGate-Source Voltage 20 VPower Dissipation79 WGate Threshold Voltage1 V 2.5 VOperating Temperature Range-55C 175 CSwitching Turn-On Delay Time15 40 nsSwitching Turn-Off Delay Time60 130 ns

Also mention diode specs and resistor specs21Cable Disc BrakesProduct SpecificationsMechanical two piece forged aluminum calipersTri-align caliper positioningDual knob pad adjustmentWeighs only 329 gramsG2 CleanSweep rotorsSintered pads

AdvantagesDurableLight weightCost effectiveSimple installationReliable in all weather conditions

ATmega328 MicroprocessorContains all code for the system Operating Voltage 1.8 to 5.5 VoltsMemory: 32 KbLow cost: $2.88

GTPA013 GPS ModuleFast TTFF: 34 seconds from cold startOperating Voltage: 3.0-5.5 VSupports up to 22 satellites Uses NMEA 0183 protocol Small and compact : 15X15X4 mmPrice: 39.95

GPS FunctionsWill contiguously update coordinate locationWhen event triggered GPS data is parsedOnly latitude and longitude will be used

M10 GSM ModuleOperating Voltage: 3.3 5.5 VCurrent consumption as low as1.2mA Has GPRS capabilities AT Commands used Affordable: $39.95M2M data plan required

GSM FunctionsWill receive a SMS Once text message is received GPS coordinates dates are parsedSMS will be sent out by module containing coordinates

LCD SCREENCharacter typeLow CostNot graphical difficult to ProgramBest type based on Project16 X 2

28LCD Screen Function Provide power levels from circuit Displays if locking mechanism is Locked/ Unlocked

LCD DIAGRAM

Lead Acid BatteryExcellent Time DurabilityExcellent Life Durability High Charge efficiency Very Cost Effective12V

Power

Printed Circuit Board

BudgetItemUnit PriceQuantityTotal CostA204 FlexiForce Sensor$19.503$58.50Atmega328$2.882$5.7620-PIN DIP Socket$0.751$0.75M10 GSM Shield$1091$109GTPA013 GPS Module$39.951$39.95LCD Screen$17.991$17.9912v Lead Battery$39.991$39.99LT1676 Switching Regulator$5.882$11.76DC Power Connectors$1.262$2.52Invacare Veranda Manual Wheelchair$991$99Parallax RFID Card Reader Module$42.991$42.99RFID 54mm x 85mm Rectangle Tag$2.501$2.50RFID Blue Eye Key Fob Tag$1.991$1.99Solenoid$54.702$109.4Avid BB7 Mechanical Disc Brake$512$102Perfboard$4.002$8.00Total$652.01Work Distribution AngeloRyanTrentLomarGPSXGSMXRFIDXSoftwareXXLCDXPressure PadsXLocking MechanismXPowerXQuestions?