Simple Line Follower Tutorial

Hiii Everyone, I am sorry for all the people who have been logging onto my blog as I haven't been updating a lot.

I would be explaining about making a line follower, using 3 and 2 sensors. I would also be telling the advantage of using 3 sensors over two sensors.

Prerequisites :

1) Have a sensor circuit ready. You can check my post to know how to make a sensor ckt.

2) Have microcontroller (I would be using atmega8). and a motor driver ready.

Setup of sensors:

Have the sensors setup on the chassis in such a way that center sensor is atleast 2cm away from left and right sensor.( Why 2cm you will know later).

Now the LOGIC part: Assuming that arena is white in colour and line is black in colour.

L C R Direction
1 0 1 Forward [ both motors move in same direction]
0 0 1 Left [ only right motor moves]
1 0 0 right [only left motor moves]
0 0 0 Forward. ( we have encountered a junction over here)


Code to be written :

#include
int L; //left sensor connected to 1st pin of Portc, which is PINC.0
int R;// right sensor connected to 2nd pin of Portc, Pinc.1
int C;// center sensor connected to 3rd pin of Portc, Pinc.2
main()
{

if(L==1&&C==0&&R==1)
{
PORTD=0xAA;
}
if(L==0&&C==0&&R==1)
{
PORTD=0x02;
}

if(L==1&&C==0&&R==1)
{
PORTD=0x88;
}

if(L==1&&C==0&&R==1)
{
PORTD=0xAA;
}

Motors are connected to PORTD pins.

When PORTD=0xAA;

AA stands in hex as 10101010 [ Most significant bit to least significant bit]

So the motor pins are connected as follows: Consider only the first four bits/pins, bcz we wont be using the last four bits/pins.

PIND.0= R-;
PIND.1= R+;
PIND.2=L-;
PIND.3=L+;

When R+,L+ are high. Both the motors would rotate in one direction.

When R+ is high, rest ground. Only the right motor would rotate.

Same thing for rest all.

I hope you did understand the code . I will be posting the ckt of it shortly.
If any queries please ask me.

MICROCONTROLLER TUTORIAL 2

WHAT ALL WILL YOU WILL BE REQUIRING TO PROGRAM A MICRCONTROLLER:

1)Firstly you would be needing a burner which will transfer a hex code from your system into the microcontroller.
So first go get this thing, I will wait for you, go get the burner and see how your robots dance with ease. The cost of the burner is not more than 500 rs including shipping charges. If you want to make your own burner then it would cost you less than 250 rs.

Places to buy micrcontroller( in india only):

www.robokits.co.in
www.extremelectronics.com
www.nex-robotics.com

If you want to make your own burner then check here:

Serial programmer click here
USB programmer click here
An another serial programmer click here

2) Now that you have a burner get a micrcontroller, buy an atmega8 it has all the features like ADC, timers, PWM , that would be enough at the start later you can change this after you know more abt micrcontrollers.

I have a burner where I bought it from extremeelectronics, and I started with ATMEGA8 top program it.

3)Now that you have all the hardware part ready , the next thing which will you be needing are a couple of softwares.

1) CODEVISION AVR:
This is the place where you will be writing your code in C language and creating a hex code.(dnt wrry I will be teaching you how to write the code).
Download this software first click here to download it.

2) The next software which will you would be needing is AVR STUDIO software.
In this software you can write the code and create a hex code also, but we will be using it only for debugging. If you dint understand what you meant by debugging, then here is wat I mean. You write the code in Codevision avr, then to know how your code works you would be translating your code from codevision avr to avrstudio. In avr studio, you can c how your ports respond by looking at a simulator which shows how your microcontroller would react in reality with the code youy have written.

3)This is the last software you would be needing, which will transfer the hex code from the computer to your microntroller. This software comes with the burner, in any case your making your burner, then there will be a reference to download the corresponding software also. If your using avr usb-asp burner , just google it and you can get it easily.
When you connect the cable (either usb or serial cable ) to the computer, you need install the hardware software( as it will consider itself as a driver). This software also comes with the burner. Just install this driver software as would do to install any normal driver software for your computer. After you have installed the software, copy paste the avr usb-asp GUI window and paste it in atmel avr studio folder.

This completes all the necessary hardware and software part to burn the avr microntroller. My next post would be tomm plz check in to know how to write a code and the basics of coding.

Microcontroller tutorials 1

Hiii,

I guess I was posting too many ckts and stuff like that , now I will be starting of with microcontroller tutorial. This would be a completed tutorial of about 4-6 posts , where I would be teaching you( infact telling you) how to program microcontrollers with ease and all the problems that you would be facing when you start with programming.

There are different kind of micrcontrollers like AVR, 8051, PIC, ARM n stuff like that. Each of these has its own speciality and each being manufactured by different companies. Now in my blog I will telling you only about AVR microcontrollers as its the most cheap and an easy microcontroller to get in your local place. The cost of burner of 8051 is a lot more than compared with PIC and AVR . AVR burners are cheap than compared to PIC. Most of the hobbyist use AVR as it satisfies thier need for the projects easily.

This is the end of my first microcontroller tutorial, check my nesxt post to know what all will be needing to program a microcontroller.

Tactile Bump Sensors

---

These are mechanical touch sensors that are used to detect environment. They are used when you need to stop the bot after it touches some thing.

These are generally used with some whiskers like wire to detect from a far distance and mostly used in beam bots as they take very less power and give also very less power.I have seen some bots which use them for sensing the obstacles rather than using IR sensors or any other sensors as they are easier to use than ny other circuit designed sensors.

The other two types of switches are the magnetic reed switch and the membrane switch, which is much like a long button actuated switch.

Sensors to be used in Line follower

Hi evryone out there , I hope evryone is fyn and njyoing robotics , last 4 months had been a very tough job for me participating in ROBOCON , though we were not successful , I learnt a lot from this compt.
The first thing I would like to share is

Which Sensors to be used to detect black line??

I tried different circuits which even removes ambient light effect ( I will be posting the ckt oif it ) and IR sensors .Though I liked IR sensors the most , I was amazed to see the results when I used LDR sensors and White light . I used white light as my transmitter and LDR with a black tape covered as my reciever. The results were very good but the opnly problem was this is more sensitive to ambient light than IR sensors , but the change in ouput voltages were arnd 2 volts where as ir sensors always gave a change in output voltage of .89 .

If u want you can use LDR sensors with out a potmeter and opamp which I showed you in my ir sensor ckt.Give a try with ldr reciver ckt by replacing the transmitter and reciver with white led and LDR sensor

4 amp Motor Driver ckt

This is a 4 amp motor driver ckt which i have used in my recent robotics competition ROBOCON where i was driving a power window motor which used to give arnd 25 kgcm torque.
Thinking abt all the financial crisis we had, I choose this ckt which reduces to dig our pocket .

As i have explained in my previous motor driver ckt that there will be two channels in a motor driver IC, each channel giving arnd 1amp in case of l2938d and 2amp in case of l298 . Now i drove both the channels in parallel and hence i was getting 4amp current, this is the most simplest of all motor driver circuits which need more current to drive motors.


W1 and W2 are the inputs, by varying the inputs with 1 and 0 we get different ouputs which drive a motor. Remember to use a heat sink and dont touch it when you turn on the power of it.
The diodes at the motor end are only needed as protective fly back diodes , to protect the motor driver ic , from the current which starts flowing from the motor in back ward direction because of switiching ON and OFF at most of the times. These diodes protect the flow of current to motor driver IC.

Photo Roller n Photovore

This is in regards is what to be told to the biggest solar bots competition in India , this is for all those who did not attend the costly workshop conducted by robosoft in co ordination with iit bombay.

The two solar bots competition photovore n photoroller , uses only solar enrgy as the power source over here the power being given by a 500 w bulb .
In photoroller which is the prelims of techfest known as nexus ,u need to travel 1 meter straight .
The problems faced by me were i didnt buy proper dimensions solar cell which gave me lot of problems , like voltage supply n dimensions.

SolarCell:
First thing to keep in mind when buying the solarcell is to fit in proper dimensions , n mind the weight of it .Next coming to the ratings of the solarcell , thinking taking higher voltage rated solarcell wuld give me more power then have in mind tat it completely depends on intensity of light falling on the solarcell n the area of the solarcell. I took a solarcell of 6v 120 mA having a dimension of 16x8cm , which was very big n had a problem in fitting it on to the bot.
By looking at other peoples bot , i decided to use a 4v 90mA rated solarcell having a dimension of less than 100cm^2 . The position of the solarcell has to be considered also , like tilting it towards the soalrenergy wuld give more power , bcz in the round of photovore the solarlamp is not perpendicular so there wuld be a problem over there.

Checking the solarcell:
When u first buy a solarcell of ny rated voltage try to hold in it in the sunlight , n check it out wth the help of a 2v rated motor , prefarable timing wuld be in the afternun when there is more sunlight. It wont move wth very high speed but still u will understand some thing.

MOTOR :
As the output power tat comes from the solar cell is of arnd 4 v it wont be able to drive the regular 12v motor, not even an inch, the only motors over here tat u can use it is the 9v 10 mA rated taperecorder motor, though 9v it can run at 1.5v wth gud speed.The speed of this motor wuld be arnd 1200rpm which means u will get zero torque.
The final thing on motors is use a taperecorder motor which runs easily at 2 v also , and try to remove the outerlayer of the motor this reduces the weight of the motor.

Chasis:
The general method which people build for solarbots is they hang thier motors at an angle of 45degrees , wth shaft touching the ground as seen in this picture .
The shaft of the motor has been wounded round by a rubber so there is a litle bit of friction to move.

But i used a toy which i got it for 50 rs it had a gear mechanism which made the output speed to come close to around 300 rpm , which also means i will be getting higher torque now . As one wld need to win the competition , one needs gud speed n not doing the traditional solarbots way try to use the gearbox of toycars only , which will give gud speeds n torque.
Circuit:
Now coming to make the motors run with the help of the solarcell . First thing is solarcell doesnt store charges n hence you cant directly connect the terminals of the solar cell to the motor, though it runs sometimes (only under sunlight n tat too at noon) . You wuld be needing a component which will store this charges n send them out instantaneuosly n hence you use a capacitor over here . The general rating of the solarcell is 4700 uF capacitor (25v ) . The capacitor stores charges upto the max limit of it n then discharges out only when u connect a motor, IT WILL DISCHARGE OUT ONLY WHEN U CONNECT THE MOTOR , CAPACITOR ACTS AS OPENCKT WHEN THERE IS NO LOAD. So u cant directly connect the motor to the capacitor bcz u wont be removing one terminal of the motor n then fixing it back . General type of ckts tat people use are :

How it Works(The FLED SE)?

First of all you should know these facts

1. In a NPN transistor current flows from emitter to collector. For this N(emitter) should be negative, P(base) should be positive and N(collector) should be negative.

2. In a PNP transistor current flows from collector to emitter. For this P(emitter) should be positive, N(base) should be negative and P(collector) should be positive.

3. Certain components like Flashing LED's , LED's etc. let current flow through them only at a particular voltage across their terminals. Let us call these components trigger elements.

In Detail

The need to use a capacitor in the solar engine arises out of the fact that the solar cell doesn't generate enough current or charges at an instant to overcome the resistance of the motor and run it efficiently. So sufficient charges are stored in the capacitor and are then discharged to the motor whenever required.

As you can see the capacitor is charged by a solar cell and continues charging till the maximum voltage of the capacitor or the solar cell (whichever is minimum) is reached, if no connections are made to the capacitor.

Let us assume that the motors used in the solar cells work most efficiently when supplied with 3 volts. So the solar cell must be capable of generating minimum 3 volts and the capacitor must also be able to store charges up to more than 3 volts.

If the motor is directly connected across the capacitor the stored charges are immediately discharged to the motor and hence the capacitor has no significance. Hence we need a circuit that will automatically discharge the energy in the capacitor to the motor when the charge in capacitor has reached the required level to run the motor efficiently.This is accomplished using the transistors, FLED and the resistor.

Charges build up in the capacitor starting from 0 volts. The base and the emitter of the PNP are positive (emitter +ve directly through the positive terminal of the cap and base through the resistor and the motor). Since both base and emitter are +ve the PNP transistor doesn't work (current doesn't flow from collector to emitter).

The PNP doesn't work until the voltage across the cap equals trigger voltage of the FLED or LED or diode. At this voltage the current flows through the trigger element. Since current flows through the trigger element ,not to the base of the PNP, the base of the PNP becomes negative. Hence the PNP conducts and current flows from the collector to emitter

Similarly the NPN doesn't conduct as the emitter(N) is negative( through the -ve of the cap) and also the base is negative. For the NPN to work current must flow from emitter to collector. For this the base must be positive. Such a situation arises only at the trigger voltage of the diode when the PNP conducts and thereby makes the base of the NPN positive. At this point current from the capacitor flows through the NPN to the motor and causes it to rotate.

Even if the voltage across the cap falls to less than the trigger voltage and the base of the PNP becomes positive, the motor continues to rotate.The rotation continues until the motor resistance becomes high enough to prevent further discharge of the capacitor. Now the voltage in the capacitor again rises until it reaches the trigger voltage of the trigger element and the above cycle repeats.

Upon notice, the starting of the motor is controlled by the trigger voltage of the trigger element and the stopping of the motor is determined by the resistance of the motor( 2 independent factors). Hence the solar engine acts like a silicon controlled rectifier (SCR).

Some links :

http://www.beamindia.net/se.htm

http://www.triindia.co.in/resources/?p=280

http://www.solarbotics.net/library/circuits/se_t1_zener.html

http://www.beam-online.com/Robots/Galleria_other/solarollers.html

Voice controlled robot

Circuit operation:

This device beeps intermittently for approx. two seconds when a person in a range of about 10 meters emits a whistle.
The first two inverters contained in IC1 are used as audio amplifiers. IC1A amplifies consistently the signal picked-up by the small electret-microphone and IC1B acts as a band-pass filter, its frequency being centered at about 1.8KHz. The filter is required in order to select a specific frequency, the whistle's one, stopping other frequencies that would cause undesired beeper's operation. IC1C is wired as a Schmitt trigger, squaring the incoming audio signal. IC1D is a 2 second (approx.) monostable driving the astable formed by IC1E & IC1F. This oscillator generates a 3 to 5Hz square wave feeding Q1 and BZ1, thus providing intermittent beeper's operation.

Notes:

• Power supply range: 2.6 to 3.6 Volts.

• Standing current: 150΅A.

• Depending on dimensions of your box, you can choose from a wide variety of battery types:

• 2 x 1.5 V batteries type: AA, AAA, AAAA, button clock-type, photo-camera type & others.

• 2 x 1.4 V mercury batteries, button clock-type.

• 1 x 3 V or 1 x 3.6 V Lithium cells.

Instead of the buzzer drive the motors, connect the inputs of an L293D inplace of BZ1 and thats it , it can move with u r voice , but u cant make it drive right or left.

If u want more help , plz ask me .

Robot tat acts like Rat

ScienceDaily (Feb. 21, 2005) — Robots that act like rat pups can tell us something about the behavior of both, according to UC Davis researchers.

This robot was designed with the same basic senses and motor skills as a rat pup. (Sanjay Joshi/UC Davis photo).

Bug Robot

Mechanical Engineers Have New Bug-Inspired Robot That Senses Its Way With Flexible Antenna.

July 1, 2005 — Researchers have developed a flexible, sensor-laden artificial antenna to help a robotic "bug" move and navigate just like the common cockroach. The bug can curry along walls, turn corners, avoid obstacles, and feel its way through the dark. In rescue operations, such robots could be sent to explore collapsed buildings and other situations that could pose hazards or just be inaccessible to humans.

HOW IT WORKS: Most robotic vehicles designed to navigate dangerous terrain rely on artificial vision or sonar systems to find the safest path. But robotic "eyes" don't operate well in low light and sonar can be confused by polished surfaces. The Johns Hopkins University scientists have turned to touch, inspired by how bugs use this sense to navigate dark rooms with varied surfaces. Just like a cockroach's antenna, the artificial version sends signals to the electronic brain of a wheeled robot, enabling the machine to scurry along walls, turn corners, and avoid obstacles in its path.

The antenna is made of cast urethane, a flexible substance that resembles rubber, encased in a clear plastic sheath. It contains six strain gauges, sensors that change resistance as they are bent. The device has been calibrated so that certain electric voltages correspond to certain bending angles as the antenna touches the wall or some other object. This data is fed to the robot's controller, enabling it to sense its position in relation to the way and to maneuver around obstacles. For instance, when the antenna signals that the robot is moving too close to a wall, the controller steers it away.

WHAT IS SWARM INTELLIGENCE: Building "swarms," of robotic insects that work together to adapt to their environment is part of "evolutionary robotics": creating machines that are digitally "bred" to evolve themselves. Swarm intelligence is the notion that complex behavior can arise from large numbers of individual agents each following very simple rules. For example, ants follow the strongest pheronome trail left by other ants to find the most efficient route to a food source, through a process of trial and error. A chunk of the plot in Michael Crichton's novel Prey was inspired in part by an experiment in which a fleet of robotic predators were programmed to seek out "prey" to get their next energy boost. The mechanical "prey," in contrast, were programmed to "graze" on special light sources and to keep alert for potential predators. The respective robots evolved increasingly complex hunting and escape strategies as the swarms of robots accumulated more and more data (in the form of experience) on which to base their decisions.

sciencedaily.com for more info.

Grass Hopper Inspired robot

About the size of a locust and weighing on 7 grams, this tiny robot can jump 27 times its own size.

Grasshopper-Inspired Jumping Microrobot Can Make Staggering Leaps

ScienceDaily (May 22, 2008) — Researchers from the Laboratory of Intelligent Systems at EPFL are unveiling a novel, grasshopper-inspired jumping robot at the IEEE International Conference on Robotics and Automation May 21 in Pasadena, California. The robot weighs a miniscule 7 grams, and can jump 1.4 meters, or more than 27 times its body size -- ten times farther for its size and weight than any existing jumping robot

Wall climber (Robotics News)

Researchers have designed a robot that uses a novel form of electrically activated adhesion to enable it to scale any kind of vertical surface. The robot can even climb surfaces that are dusty or wet, be they concrete, glass, or drywall.

"What's really unique about this is the technology, not the robot," says Harsha Prahlad, senior mechanical engineer at SRI International, a nonprofit research organization based in Menlo Park, CA. There are other robots that can climb walls. But these have usually involved using microscopic fibers designed to mimic the function of the hairlike setae that give geckos their remarkable sticking power, Prahlad says.

In contrast, SRI's robot works by inducing electrostatic charges in the surface of a wall. The advantage here is that the adhesive climbing surfaces of the robot can be turned off, making movement much simpler, says Prahlad. It also makes the robot's adhesive surfaces self-cleaning, he says, thereby avoiding any gradual buildup of dust and dirt that would ultimately reduce the adhesion.

Tests have shown that the robot is capable of generating 1.5 newtons of sticking force per centimeter square of contact with a wall. Presenting his results at this year's International Conference on Robotics and Automation, in Pasadena, CA, Prahlad showed that the robot was able to scale walls while carrying weights of up to 75 pounds.

"It's an interesting and robust approach," says Metin Sitti, a mechanical engineer at Carnegie Mellon University, in Pittsburgh, who has been working on wall-climbing robots for some time. However, he says, the forces generated are just one-tenth as strong as is currently being seen when the gecko-inspired approach is used.

On the plus side, however, the simplicity of Prahlad's approach should make it easier to apply to human wall-climbing applications, says Nicola Pugno, a professor of structural mechanics at Turin Polytechnique, in Italy, who has been working on a sort of Spiderman suit using nanotube-covered adhesive surfaces.

"There is no fundamental reason why you can't scale this up to, say, 200 pounds," says Prahlad. So with a suitable interface, it should be possible to allow a human to use this technology to climb walls, he says. However, such a system would require large pads to increase the surface contact of a person's hands. Otherwise, there would not be enough sticking power to support his or her weight, says Prahlad.

The attractive forces that create the adhesion come from electric fields generated by positive and negative electrodes within the surface pads of the robot, says Prahlad. When a high voltage is applied to these electrodes, positive and negative charges build up, which, in turn, attracts opposite charges from the surface of a wall near the electrodes

Simple line follower using logic gates

This is a simple line follower using two sensors and without a microcontroller. We use here two types of logic gates and Lm 324 for the sensors. Two "OR" logic gates and one "Ex-OR" logic gates.The relay is used to run motors , can be replaced with motor driver L293D .

The ckt is self xplanatory , if u want to know the logic of its wrkng r have problem in understanding , wat its logic is , ask me and I will help you.

IR sensors From Scratch + Line follower

IR emitter and IR phototransistor
An infrared emitter is an LED made from gallium arsenide, which emits near-infrared energy at about 880nm.
The infrared phototransistor acts as a transistor with the base voltage determined by the amount of light hitting the transistor.
Hence it acts as a variable current source. Greater amount of IR light cause greater currents to flow through the collector-emitter leads.
As shown in the diagram below, the phototransistor is wired in a similar configuration to the voltage divider.
The variable current traveling through the resistor causes a voltage drop in the pull-up resistor.
This voltage is measured as the output of the device






IR reflectance sensors contain a matched infrared transmitter and infrared receiver pair.
These devices work by measuring the amount of light that is reflected into the receiver.
Because the receiver also responds to ambient light, the device works best when well shielded from abient light,
and when the distance between the sensor and the reflective surface is small(less than 5mm).
IR reflectance sensors are often used to detect white and black surfaces. White surfaces generally reflect well,
while black surfaces reflect poorly. One of such applications is the line follower of a robot.









Schematic Diagram for a Single Pair of Infrared Transmitter and Receiver











To get a good voltage swing , the value of R1 must be carefully chosen. If Rsensor = a when no light falls on it and Rsensor = b when light falls on it. The difference in the two potentials is:

Vcc * { a/(a+R1) - b/(b+R1) }
Relative voltage swing = Actual Voltage Swing / Vcc
= Vcc * { a/(a+R1) - b/(b+R1) } / Vcc
= a/(a+R1) - b/(b+R1)

The resistance of the sensor decreases when IR light falls on it. A good sensor will have near zero resistance
in presence of light and a very large resistance in absence of light. We have used this property of the sensor to form a potential divider. The potential at point ‘2’ is Rsensor / (Rsensor + R1). Again, a good sensor circuit should give maximum change in potential at point ‘2’ for no-light and bright-light conditions. This is especially important if you plan to use an ADC in place of the comparator

To get a good voltage swing , the value of R1 must be carefully chosen. If Rsensor = a when no light falls on it and Rsensor = b when light falls on it. The difference in the two potentials is:
Vcc * { a/(a+R1) - b/(b+R1) }

Relative voltage swing = Actual Voltage Swing / Vcc
= Vcc * { a/(a+R1) - b/(b+R1) } / Vcc
= a/(a+R1) - b/(b+R1)




If the emitter and detector (aka phototransistor) are not blocked, then the output on pin 2 of the 74LS14 will be high (apx. 5 Volts).
When they are blocked, then the output will be low (apx. 0 Volts). The 74LS14 is a Schmitt triggered hex inverter.
A Schmitt trigger is a signal conditioner. It ensures that above a threshold value, we will always get "clean" HIGH and LOW signals.
Not Blocked Case: Pin 2 High Current from Vcc flows through the detector. The current continues to flow through the base of Q2.
Current from Vcc also flows through R2, and Q2's Drain and Emitter to ground.
As a result of this current path, there will be no current flowing through Q1's base.
The signal at U1's pin 1 will be low, and so pin 2 will be high. Blocked Case: Pin 2 Low Current "stops" at the detector.
Q2's base is not turned on. The current is re-routed passing through R2 and into the base of Q1.
This allows current to flow from Q1's detector and exiting out Q1's emitter. Pin 1 is thus high and pin 2 will be low.
To detect a line to be followed, we are using two or more number of poto-reflectors.
Its output current that proportional to reflection rate of the floor is converted to voltage with a resister and tested it if the line is detected or not.
However the threshold voltage cannot be fixed to any level because optical current by ambent light is added to the output current.
Most photo-detecting modules are using modurated light to avoid interference by the ambient light.
The detected signal is filtered with a band pass filter and disused signals are filtered out.
Therefore only the modurated signal from the light emitter can be detected.
Of course the detector must not be saturated by ambient light, this is effective when the detector is working in linear region.






The line position is compeared to the center value to be tracked, the position error is processed with Proportional/Integral/Diffence filters
to generate steering command. The line folloing robot tracks the line in PID control that the most popular argolithm for servo control.
The proportional term is the commom process in the servo system. It is only a gain amplifire without time dependent process.
The differencial term is applied in order to improve the responce to disturbance, and it also compensate phase lag at the controled object.
The D term will be required in most case to stabilize tracking motion. The I term that boosts DC gain is applied in order to remove left offset error,
however, it often decrease servo stability due to its phase lag.
When any line sensing error has occured for a time due to getting out of line or end of line, the motors are stopped and
the microcontroller enters sleep state of zero power consumption.
Typical Examples of infrared Transmitter and Receiver installation

Maze Solver n Wall Follower .

A simple wall follower has to navigate easily following the wall , that is when evr there is a turn (perfect 90 degree as by the wall) the bot shuld also take a turn . Take a look at this picture .



First question which comes to your mind is how many sensors do one wuld need ?? . Wuld we need a micrcontroller .

Well we can make this by using only two sensors , and there is no need of a micrcontroller also.

CONDITIONS TO BE SET UP:

We wuld be using 2 sensors one at the rite and the other at the center .

(Left sensor- high ----------and center sensor- high

move fwd)

(Left sensor-low ----------and center sensor-high

take left)

(Left sensor-high ----------and center sensor -low
take rite).

Use a K map with the above conditions and get the logic circuit .
Connect the sensors to the input of u r logic and H bridge at the output.
Use motors of 60rpm nt faster than tat .

If u want more help plz ask.

COLOUR SENSORS

All color sensors work on the basic principle that when light of some color falls on an object , if the object is of same color as of the led , then the object absorbs that color which means there is no reflection.

We would be making the ckt in the same way as we did for the IR led detector ckt , but we wuld be using LDR for our detection purpose , (IR cant be used as they catch only IR waves) , and in place of the IR transmitter we wuld be using three leds of red, blue and green.

WORKING:
Light up each of the leds one at a time , ie red , then blue n green , if the obstacles are of red blue and green colour then you wuld be getting different outputs ( REMEMBER VIBGYOR) .

With micrcontrollers , lit up the red led if there is reflection take the ADC reading
do the same for other leds and take thier ADC reading , we will know which colour its detecting.
One sensor wuld be lit up always .





Use a potentiometer with each of the LEDs to get a better reading , as there wuld be slight color difference .The circuit will be the same as for the ir sensor which i have explained in my previous post , with litlle changes .Hope u njyd it

BUMP SENSOR

So, you've fitted some motors to your robot and its happily driving around but it probably keeps colliding with obstacles and getting stuck. You need a way for your robot to detect collisions and move around objects. Enter the humble bump sensor:

A bump sensor is probably one of the easiest ways of letting your robot know it's collided with something. The simplest way to do this is to fix a micro switch to the front of your robot in a way so that when it collides the switch will get pushed in, making an electrical connection. Normally the switch will be held open by an internal spring.

Micro switches are easy to connect to micro controllers because they are either off or on, making them digital. All micro controllers are digital, so this is a match made in heaven. Micro switch 'bump' sensors are easily connected to the Robocore, simply plug them into any free digital socket and away you go.

The following diagram shows a typical circuit for a micro switch bump sensor. The resistor is important because it holds the signal line at ground while the switch is off. Without it the signal line is effectively 'floating' because there is nothing connected to it, and may cause unreliable readings as the processor tries to decide if the line is on or off.

If you dont get these microswitches u can make one easily , using a spring mechanism.

MORE E BOOKS

(1)

Robots Androids & Animatrons by John Iovine

download from here
Lovely book , gives u a good start for professional robotics.

What u can get from this book????

Movements and drive system.

DTMF controlled vehicle (tats using u r phone)

Making a walker

Speech Controlled bot

Under water bots

Aerobots

One necessary book , I double my money on this to read.

(2)

Robotics and Process Control Cookbook

download from here


Not tat great to read on if u have other e books , but has gud examples of various things.

(3)

Build a Remote Controlled Robot

download from here

Diff methods of making a remote controlled car , from Ir , Rf to various methods.

(4)

8051 microcontoller

download from here

One stop to start for micrcontrollers r download ayalas e book from my other post on e books.

BIOMETRIC ROBOT JOURNALS

This another list on robotic journals on biometric , can be used for paper presentation in engineering .Taken from societyofrobots.com one wonderfull site.

Adaptive Dynamic Walking of a Quadruped Robot on Irregular Terrain Based on Biological Concepts

Biomimetic Robot Navigation

Biomimetics: New Tools for an Old Myth

A New Hybrid Approach to Dynamic Modeling and Control Design for a Pectoral Fin Propelled UUV

Design of a Biomimetic Controlled-Curvature Robotic Pectoral Fin

A Novel Water Running Robot Inspired by Basilisk Lizards

Review of Fish Swimming Modes

Trends in Biorobotic Autonomous Undersea Vehicles (4.7mb)

Walking Robots and the Central and Peripheral Control of Locomotion in Insects

ARTIFICIAL INTELLIGENCE - ROBOTICS JOURNALS

Here is a list of journals , papers that engineering students can use for paper presentations , but shld have great fundas .

Cognitive Architecture, Concepts, and Introspection: An Information-Theoretic Solution to the Problem of Phenomenal Consciousness

CoSy: Cognitive Systems for Cognitive Assistants

Emerging Consciousness as a Result of Complex-Dynamical Interaction Process

Levels of Consciousness and Self-Awareness: A Comparison and Integration of Various Views

Single-Neuron Theory of Consciousness

Reinforcement Learning: A Survey