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P. Indra Reddy Memorial Engineering
College.
-Department of Electronics &
Communication
Handicap Assistance Device for Appliance
Control Using User Defined Gestures
Under the guidance of
T.k.Padmalatha
By
Naresh (07J81A0425)
Narayan Reddy (07J81A0423)
Block Diagram Left hand control
14
Contact
buttons
Power
supply
X&Y
Accelerometer
Left Hand
MCU
Tilt
buttons
Piezoelectric
Buzzer
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 input
Used for the purpose of tilt monitoring
Here the accelerometer will calculates the tilting angle,
position of tilting
Features & Applications
Integral Signal Conditioning
High Sensitivity
Linear Output Robust Design
Transducer Hermetically Sealed at Wafer Level for Superior
Reliability(especially against the escape or entry of air.)
Typical Applications
Tilt Monitoring
Inclinometers
Inclinometer or clinometer is an instrument for measuring
angles of slope,tilt, elevation or depression of an object with
respect to gravity
Appliance 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 device
Here 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
Tilt state
buttons
Flex
sensor
5 DOF
Sensor
Right Hand
MCU
Positions of right Hand
Flex Sensor (FS-L-0112-103-ST):
FS
L
0112
103
FLEX
SENSOR
LINEAR
ACTIVE
LENGTH
RESISTAN
CE
SERIES
MODEL
112.24mm
10KOhms
Features
•Angle Displacement Measurement
•Bends and Flexes physically with motion device
•Gaming (Virtual Motion)
•Computer Peripherals
•Simple Construction
ST
ST
SOLDER TAB
How it works
We mounted this sensor on right index finger
sensor 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)
• 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 noninverting pin rises and the op amp outputs a high signal to the
MCU.
5 Degrees of Freedom Sensor
FEATURES
• 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 package
Quad 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.
Base station
Packet
radio
Raw input request
(wire less)
Packet
radio
MCU based
receiver
(Wired)
MCU based
USB
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 Rate
Frequency-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 Mode
A 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
PB0
PB1
PB2
PB3
PB4
PB5
PB6
PB7
RST IN
VCC
GND
XTAL1
XTAL2
PD0
PD1
PD2
PD3
PD4
PD5
PD6
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
A
T
6
4
4
P
A
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
Pin Diagram
PA0 (AD0)
PA1 (AD1)
PA2 (AD2)
PA3 (AD3)
PA4 (AD4)
PA5 (AD5)
PA6 (AD6)
PA7 (AD7)
AREF
GND
AVCC
PC7 (A15)
PC6(A14)
PC5(A13)
PC4(A12)
PC3(A11)
PC2(A10)
PC1(A9)
PC0(A18)
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 Registers
High 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)