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5thh ational robot contestational robot contestresentation on generalresentation on generalspects of electronicsspects of electronics
Presented by
Deepak ParajuliGiresh kunwar
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What is ROBOT
widely used in manufacturing, assembly andpacking, transport, earth and space exploration,
surgery, weaponry, laboratory research, andmass production of consumer and industrialgoods.
v ,an automatically controlled, ,reprogrammable multipurpose manipulator
,programmable in three or more axesfixed or mobile
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ROBOT DissectionMechanical body
Electronic automation
Automatic movement ormanual control
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Major ElectronicsHardwarevSensorsvMain controller (robot brain)
vMotor drivers and actuators
SoftwarevLanguage and Tools(assembly ,c , keil, mplab)vSimulators(proteus, EWB)
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General Block Diagram of
Robotic System
Microcontroller
sensor
sensor
sensor
Se
nsor
condition
ing
Out
put
interfaces
actuator
indicator
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sensorsTouch sensorPhoto diode
Photo transistorLDR
IR
Ultra Sound
Image sensorGyro sensor
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Sensors(cont...)
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Use of sensorsWhite strip(line) detectionProximity detection
Obstacle detectionObstacle avoidance
Inter robot communication
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Main controller(robot
brain)Different families of microcontroller ATMEL, Motorola, Texas Instuments, Zilog
Microchip PIC
AVR etc.Selection Criteria of microcontrollerComputing needs of the task efficiently(speed, memory, I/O ports, Power
consumption, cost/unit)
Availability of software development tools(compiler,
simulator, assembler, debugger, technical support)Market availability
Availability of reliable source of information
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Motor Driver circuits and
MotorsElectromechanical Relay switchingRelay driver(ULN 2 0 0 3 )
MOSFET H- bridgeMotors
Wiper motor (high torque low speed)
Dc motor (moderate torque/ moderate speed)
Stepper motor (precise control/low torque)
OptocouplersBlocking the noise from motor controller and motors to pass
to the main controller circuit.
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Motors (cont...)
W ip e r
m otor
Step pe rm otor
G e a r h e a d e d D Cm otor
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H- bridge
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Relay switching
D P D P re la y w ith
ice cubep acka g in g
D iffe re n t rela ysw itch in g
S o lid sta te re la y
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PCB designing Mechanical etching(etching machine takes more than 1 hr) Chemical etching(Conc HCl and H2O2 takes 30 minutes)
Single layer PCB
Double Layer PCB
Multi layer PCB
Circuit design considerations Avoid large looping of wires (cause noise coupling)
Avoid large component leg length(acts as antenna in high
frequency) Greater conductor spacing (to reduce noise coupling)
Avoid ground looping(to eliminate unwanted current to flow)
Place decoupling capacitor across each IC (to eliminate noise topass to the IC)
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Software aspects of
microcontrollerIt deals with inputs that comes from real world
and give output to the real world.
Popular microcontrollers: 8051 family : AT89s51, AT89s52, AT89C51,
AT89C52 PIC family : PIC16F877A AVR controllersPIC and AVR controllers available in markets have
extra features like PWM,ADC than 8051.
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On-Chip Facilities OverviewAT89S51
Parallel Input/Output PortsSystem Clock Generator
Timer/CountersInterruptsSerial Port
PIC 16F877A
PWMADC
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Parallel Input/Output
PortsFour 8-bit I/O ports.Each bit is individually usable for up to 32 1-bit
ports.
All ports are bidirectional and direction can beset in SFRs in software.
Some of the pins have alternate functions.
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System Clock Generator
8051 uses 12 system clock cycles per machinecycle.
PIC 16F877A uses 4 system clock cycles permachine cycle.
In p u t
circu it S yste m C lo ck
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Timer / Counters8051 has two 16-bit programmable timers.Timers increment on each system clock.
vEach timer is associated with correspondingSFRs (TLx, THx, TMOD) and can be read orwritten to.
Uses
Generate delay.Measure time interval between events.
Generate time out signals.
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Interrupts8051 has five sources of interrupts:Two External Hardware Interrupts
Two Timer interrupts
Serial port events (buffer full, buffer empty)
Interrupt enabled or disabled using SFRs(IE,
TCON).
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Serial Port (UART)8051 has one serial port.
Data can be sent and received serially.
Baud rate must agree between sender andreceiver.
Transmission modes are selected usingSFRs(SCON).
S e ria lPort
( )T X tra n sm it
( )R X receive
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Pulse Width
Modulation(PWM)Used for generating variable speed.PWM uses single bit output to generate an
analog value proportional to the desired
speed of the motor.
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Software tools and
languages a n g u a g e s w e h a ve b e e n u sin g to m a ke:ra in o f R o b o t
Assembly language C language
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Software tools and
languagesSoftware tools used to simulate brain ofRobot:
SDCC(small device c compiler, free and open
source) Keil (free version is limited .... Like it can debugonly 2k out of 8k code in at82s52,produce hexfile of max size up to 16k)
MPLAB IDE(free IDE provided by MPLAB for PICcontrollers bundled with assembler s and Ccompilers and debuggers from various vendorsbut these compilers are limited in free version
Proteus VSM
Software tools for AVR are generally free and opensource
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Best of luck for 5th national robot
contest
Thank you