-Department of Electronics &

Communication

Handicap Assistance Device for Appliance Control Using User Defined Gestures

Under the guidance of T.k.Padmalatha

 ByNaresh (07J81A0425)

  Narayan Reddy (07J81A0423)

Block Diagram Left hand control

X&Y Accelerometer

Piezoelectric Buzzer

Tiltbuttons

14Contact buttons

Left Hand MCU

Power supply

Positions of left hand

Accelerometer MMA 2260D

An accelerometer is a device that measures the proper acceleration of the device.Proper acceleration: the acceleration of a body relative to a free-fall condition, is measured by an instrument called an accelerometer.Acceleration is the measure of how fast the system responding to the inputUsed for the purpose of tilt monitoringHere the accelerometer will calculates the tilting angle, position of tilting

Features & Applications

Integral Signal ConditioningHigh SensitivityLinear Output Robust DesignTransducer Hermetically Sealed at Wafer Level for Superior Reliability(especially against the escape or entry of air.)Typical ApplicationsTilt MonitoringInclinometersInclinometer or clinometer is an instrument for measuring angles of slope,tilt, elevation or depression of an object with respect to gravityAppliance Control

Contact sensors

Contact sensors are simply a collection of 3M Red Dot electrodes mounted around the fingers and palms and connected to various input pins on the MCU.Red Dot Repositionable Electrodes are quick to stick on skin but gentle on removal.The input pins have the internal pull-up resistor activated.

Piezo electric buzzer

A Piezo buzzer is made from two conductors that are separated by Piezo crystals. When a voltage is applied to these crystals, they push on one conductor and pull on the other. The result of this push and pull is a sound wave.

Reset buttons

 A Reset button is a button that can reset a deviceHere it will resets the positions of the hand

Final left hand glove

Logical structure of left hand

The MCU in the left hand controller takes measurements from a pair of accelerometers to calculate the current tilt position of the hand.

Note that the tilt positions can be reset via pushbuttons. Additionally, it determines which finger or hand contact is currently activated.

These readings are then passed over to the MCU in the right hand controller, which is connected by wire.

Optionally, the left hand controller can output audio through a piezoelectric buzzer, where the frequency of the audio corresponds to the current tilt of the hand as mentioned above.

Block Diagram Right hand control

Flexsensor

Tilt statebuttons

5 DOFSensor

Right Hand MCU

Positions of right Hand

LFS 0112 103 ST

LINEAR ACTIVE LENGTH

STRESISTANCE

FLEX SENSOR

SERIES MODEL 112.24mm 10KOhms SOLDER TAB

Flex Sensor (FS-L-0112-103-ST):

Features•Angle Displacement Measurement•Bends and Flexes physically with motion device•Gaming (Virtual Motion)•Computer Peripherals•Simple Construction

We mounted this sensor on right index fingersensor increases resistance from approximately 8 kOhms to 12 kOhms when the index finger is curled in.

Flat (nominal resistance)

45° Bend (increased resistance)

90° Bend (resistance increased further)

How it works

• Sensor increases resistance from approximately 8 kOhms to 12 kOhms when the index finger is curled in.

• We put this sensor in a resistive voltage divider split across the non-inverting pin of an op amp.

• We fed the middle terminal of a trim pot into the inverting pin to allow for calibration.

• When the index finger is curled in, the voltage at the non-inverting pin rises and the op amp outputs a high signal to the MCU.

5 Degrees of Freedom SensorFEATURES• Integrated X- and Y-axis gyro on a single chip• Integrated low-pass filters• 3V single supply operation• RoHS compliant (completely lead free)Directive on the Restriction of the use of certain Hazardous Substances in electrical and electronic equipment.• QFN packageQuad Flat No leads package

It is actually a breakout board that combines the Analog Devices ADXL330, which is a 3-axis +/- 3g accelerometer, and a 2-axis 500 degree/sec gyro, the IDG300. We had originally hoped to use the gyros to control mouse cursor movement since they measure rotational acceleration about an axis.The IDG-300 is an Integrated Dual-axis angular rate sensor (Gyroscope).A gyroscope is a device for measuring or maintaining orientation, based on the principles of conservation of angular momentum

Logical structure of right hand

• The right hand consist of a 5DOF sensor, tilt state buttons, and flex sensor.

• The right hand MCU takes measurements from a pair of accelerometers within a 5 degrees of freedom sensor package, flex sensors, and pushbuttons to determine the current gesture.

• Next, the right hand MCU processes all readings from both hands them and converts them into the corresponding keyboard or mouse inputs.

• The requested keyboard and mouse inputs are then wirelessly transmitted to the base station via a packet radio.

Packetradio

Packet radio

Raw input request (wire less)

Base station

MCU based receiver

MCU basedUSB

(Wired)

Radiotronix Transceiver (Wi.232FHSS-25-R):

We had previously used the Radiotronix transmitters and receivers, which transmit at a maximum of 2400 bps. This was too slow for sending mouse input requests at a responsive rate. We noticed mouse input lag on the order of hundreds of milliseconds when sending both mouse and keyboard input requests. Therefore, we decided to use these packet radios instead to transmit at the higher rate of 57600 bps in one of several selectable channels in the 902-928 MHz spectrum. This allowed us to transmit our entire block of keyboard and mouse input requests with no noticeable input lag whatsoever.

Features • 16-bit CRC Error Checking• 153.6 kbit/ sec Maximum RF Data RateFrequency-hopping spread spectrum (FHSS) is a method of transmitting radio signals by rapidly switching a carrier among many frequency channels, using a pseudorandom sequence known to both transmitter and receiver• GUID Addressing ModeA globally unique identifier or GUIDis a unique reference number used as an identifier in computer software• Flexible User Addressing Mode``

Operating states

• The primary active state is the RX SCAN state.• When the module is not actively transmitting or receiving

packets, it is in this state.• It is cycling from one channel to another throughout the hop

sequence looking for a synchronizing packet.• If the module detects a pre-amble, it will stall the next hop to wait

for the startcode and packet header.• Standby,Sleep,Deep sleep.

USB

• The Universal Serial Bus standard allows devices to communicate with a host controller.

• USB is a common connection method for devices in a number of classes, including storage devices, human interface devices, image capture sources, and audio devices.

• USB is hot-swappable, meaning that devices can be replaced in a running computer without the need to reboot the computer

• USB provides a data rate of 12 Mbps at full bandwidth

Working of USB

• USB provides a +5V DC line, a ground line, a Data+ line, and a Data- line.

• When Data+ exceeds 2.8V with a 1.5 kOhm resistor to ground

• When Data- is less than 0.3V with a 1.5 kOhm resistor to 3.6V, a 1 is transmitted.

• When Data+ is less than 0.3V and Data- exceeds 2.8V, a 0 is transmitted.

• We have included these resistors.

Logical structure of base station

• The base station consists of a pair of MCUs.

• One of them is connected to a second packet radio that receives the incoming data from the hand controllers.

• This incoming raw data is simply forwarded to the second base station MCU, which runs the software USB program and communicates the requested keyboard/mouse input to the computer through the USB port

1 40 2 393 384 375 366 A 357 T 348 6 339 4 3210 4 3111 P 3012 A 2913 2814 2715 2616 2517 2418 2319 2220 21

PA0 (AD0)PA1 (AD1)PA2 (AD2)PA3 (AD3)PA4 (AD4)PA5 (AD5)PA6 (AD6)PA7 (AD7)AREFGNDAVCCPC7 (A15)PC6(A14)PC5(A13)PC4(A12)PC3(A11)PC2(A10)PC1(A9)PC0(A18)

PB0 PB1 PB2 PB3 PB4 PB5 PB6 PB7 RST IN VCC GND XTAL1 XTAL2 PD0 PD1 PD2 PD3 PD4 PD5 PD6

Pin Diagram

FEATURES

• 40-pin PDIP

• High-performance, Low-power Atmel AVR 8-bit Microcontroller

Peripheral Features

• Two 8-bit Timer/Counters and Compare Modes

• One 16-bit Timer/Counter Compare Mode, and Capture Mode

• Real Time Counter with Separate Oscillator

• Four PWM Channels

• 8-channel, 10-bit ADC

• 131 Powerful Instructions – Most Single-clock Cycle Execution

–32 General Purpose Working RegistersHigh Endurance Non-volatile Memory segments– 16 Kbytes of In-System Self-programmable Flash program memory– 512 Bytes EEPROM– 1 Kbyte Internal SRAM– Write/Erase Cycles: 10,000 Flash/100,000 EEPROM– Data retention: 20 years at 85°C/100 years at 25°C(1)