Autonomous Manual

8/6/2019 Autonomous Manual

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AUTONOMOUS ROBOTICS MANUAL ver 1.1


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Index

1. Sensors2. On Board Computer(OBC)

2.1Microcontroller ATMEGA 162.2LCD

3. Motor driver(L293d)4. Voltage regulator(7805)


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SENSORS

The development PCB of the infrared sensor has one IR transmitter and one IR

receiver . Now the IR sensor transmits the IR signal and the reflected IR signal

is received by the receiver . The received IR signal is weak and need to be

compared hence we use an OP_AMP IC as comparator to compare the voltage

levels and give us the desired output .Now the desired analog signal has been

achieved with the op-anp IC.This analog signal is provided to the ADC of the

microcontroller.

As you can see there are 3 tiny holes in the PCB which represent the ground

voltage and the analog value respectively.Now take the 3 3 pin bus wire that

has been provided to you and solder it to the back view of the PCB carefully so

that the two adjacent pins are not shorted.

The power to the IR sensor module is provided by the ADC itself with the

voltage and the ground pins .


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ON BOARD COMPUTER(OBC)

The board contains a red colour strobe with two wires pinging out

connect a 9-12 v dc battery or an adapter to those wires.

MICROCONTROLLER-ATMEGA16

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

Advanced RISC Architecture

131 Powerful Instructions Most Single-clock CycleExecution

32 x 8 General Purpose Working Registers

Fully Static Operation

Up to 16 MIPS Throughput at 16 MHz

On-chip 2-cycle Multiplier Nonvolatile Program and Data Memories


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16K Bytes of In-System Self-Programmable Flash

Endurance: 10,000 Write/Erase Cycles

Optional Boot Code Section with Independent Lock Bits

In-System Programming by On-chip Boot Program

True Read-While-Write Operation

512 Bytes EEPROMEndurance: 100,000 Write/Erase Cycles

1K Byte Internal SRAM

Programming Lock for Software Security

JTAG (IEEE std. 1149.1 Compliant) Interface Boundary-scan Capabilities According to the JTAG Standard

Extensive On-chip Debug Support

Programming of Flash, EEPROM, Fuses, and Lock Bits through

the JTAG Interface

Peripheral Features Two 8-bit Timer/Counters with Separate Prescalers and

Compare Modes

One 16-bit Timer/Counter with Separate Prescaler, Compare

Mode, and Capture

Mode

Real Time Counter with Separate Oscillator

Four PWM Channels 8-channel, 10-bit ADC

8 Single-ended Channels

7 Differential Channels in TQFP Package Only2 Differential Channels with Programmable Gain at 1x, 10x, or

200x

Byte-oriented Two-wire Serial Interface

Programmable Serial USART

Master/Slave SPI Serial Interface

Programmable Watchdog Timer with Separate On-chip

Oscillator

On-chip Analog Comparator

Special Microcontroller Features Power-on Reset and Programmable Brown-out Detection

Internal Calibrated RC Oscillator

External and Internal Interrupt Sources

Six Sleep Modes: Idle, ADC Noise Reduction, Power-save,

Power-down, Standby

and Extended Standby

I/O and Packages


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LCD

The display used here is 16x2 LCD (Liquid Crystal Display); this

means 16 characters per line by 2 lines. A very popular

standard exists which allows us to communicate with the vast

majority of LCDs regardless of their manufacturer. Thestandard is referred to as HD44780U, which refers to the

controller chip which receives data from an external source (in

this case, the Atmega16) and communicates directly with the

LCD. The 44780 standard requires 3 control lines as well as

either 4 or 8 I/O lines for the data bus. Here we are using 8-bit

mode of LCD, i.e., using 8-bit data bus.

The three control lines are referred to as EN, RS, and RW.

The EN line is called "Enable." This control line is used to tell

the LCD that we are sending it data. To send data to the LCD,our program should make sure this line is low (0) and then set

the other two control lines and/or put data on the data bus.

When the other lines are completely ready, bring EN high (1)

and wait for the minimum amount of time required by the LCDdatasheet (this varies from LCD to LCD), and end by bringing it

low (0) again.

The RS line is the "Register Select" line. When RS is low (0),

the data is to be treated as a command or special instruction(such as clear screen, position cursor, etc.). When RS is high

(1), the data being sent is text data which should be displayed

on the screen. For example, to display the letter "T" on the

screen you would set RS high.

The RW line is the "Read/Write" control line. When RW is low(0), the information on the data bus is being written to the


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LCD. When RW is high (1), the program is effectively querying

(or reading) the LCD. Only one instruction ("Get LCD status") is

a read command. All others are write commands--so RW will

almost always be low.

In our case of an 8-bit data bus, the lines are referred to as

DB0, DB1, DB2, DB3, DB4, DB5, DB6, and DB7.

The figure below is to show the pin diagram of before

mentioned LCD.


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LCD Circuit:

Testing (D.C. Conditions):

-> PIN 7 to 14 are data pins.

-> Voltage at pin 2 is +5.00V

-> Pin 3 is connected to 10K variable resistance for contrast

setting.

-> Pin 4, 5, 6 are control lines connected to PORT D.


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MOTOR DRIVER(L293D)

This chip is used to control two DC motors there are 2 inputs and two outputs

as shown in the figure above.

The behaviour of motors for various input conditions are as follows.

The motor driver is mostly used to boost up the voltage signal received by the

microcontroller to meet its voltage levels and show an efficiency as an

actuator.

For example if we consider this case the voltage signal provided by the

microcontroller is very low i.e around 3-5 v whereas our DC motor has a

requirement of voltage level of 12 volts.Hence we use a motor driver to boost

up the voltage signal to 12 volts from 3-5 volts.


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VOLTAGE REGULATOR(7805)

This voltage regulator IC has an input range of 9 -12 volts. The main function of

this voltage regulator IC is to step down the DC voltage level from 9 -12 volts to

5 volts since the operating voltages of our microcontroller i.eATMEGA16 is 5

volts. In the digital domain in concern with the microcontroller ATMEGA16

LOGIC 1= 5V

LOGIC 0=0V

In the notation of our IC number i.e 7805 the 5 at the end signifies the output

voltage that is desired.

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