Introduction:
We design this vehicle for future automation. Assume that if any small robot is moving on the table then can it is possible robot can not fall from the table, when robot move to the end of table then robot sense the depth and at that time depth sense provide a signal to the microprocessor to stop the vehicle . It is also possible to reverse the robot on the table by using reversing the motor. When we reverse the motor then again we require a one more depth sensor on the back side of the robot.
For the depth sensing we use inra red rays . one photodiode and one infra red is connected in pair with the vehicle. We design the circuit so that when any car move on the track then both infra red sensor, front and back reflect the rays and circuit sense the track. If the track is okay then circuit sense the rays and move the motor forward. When the vehicle move forward then if the track is going to the depth region then infra red rays are not reflected from the surface and due to that processor get a signal and . vehicle move backward automatically.
In this project we use ic 89c2051 microcontroller as a main processor. IC 89c2051 is a 20 pin microcontroller. This ic is a 20 pin version of 40 pin main atmel ic 89c51 microcontroller. We program this ic with the help of computer. Software is written in the assembley language and then transfer into the blank ic with the help of programmer kit.
In addition with the anti falling concept we use auto collosion concept.
In this project we show that how we design a future vehicle for automation. By using this automation we design the vehicle for auto path finding. We use this concept for remote area. Where we control the robot from remote are . Or we send the machine in any small tunnel. If we fit a wireless camera with this robot then it is possible for us to capture the all detail of facing area.
In this project we use two sensor. These sensor are reflective type sensor. When infra red rays reflective from any surface then we sense this reflective signal and pass to the microcontroller circuit. Microcontroller circuit sense the input signal and compare this signal with the other eye signal and then change the direction of one motor. When there is no deflection from any sensor then there is no signal from the sensor and at that time both the motor of the vehicle run smoothly to the forward direction.
In this vehicle we use total two motor for the forward and reverse direction. When one motor stop then vehicle change its direction for a short second and then again came to the origional position.
Main circuit is based on the microcontroller. Here in this project we use 89c2051 microcontroller as a main processor. Motor’s control by a H bridge circuit. For two motor we use two H bridge circuit. Here in this project we use two slow speed dc gear motor .
P1.0 and p1.1 is connected to the one motor. When both the pins are high logic then motor stop. At the same time when both the pins are 0 then again motor stop. To move a motor forward and reverse we provide a high logic on one pin and 0 logic on second pin. If we change the logic 0 and 1 then we change the direction of motor
BASIC OF ROBOTICS
ROBOTICS:
A mechanical device that sometimes resembles a human and is capable of performing a variety of often complex human tasks on command or by being programmed in advance is defined as a robot
A Robot never becomes fulfill until it can take decisions. We can’t go for computers for the computation & intelligence. But we can use single chip microcontrollers for controlling. This robot is not going to do any big tasks there will only be predefined tasks. The robot’s full control is embedded into one chip which is otherwise known as embedded systems designing.
To make a robot we must surely know to at least use a single microcontroller. So let us see about Embedded System thru 8051.
What is Open SYSTEM?
An open system is the normal desktop computer where you can use it for any tasks. If you want to process text documents you can install Ms-word if you want to send mail you can use outlook express and counts on.
What is Embedded System ?
An embedded system is the system where you can use it for a specific task.
Microcontroller:-
A microcontroller (often abbreviated MCU) is a single computer chip that executes a user program, normally for the purpose of controlling some device hence the name microcontroller.
A microcontroller is differed from microprocessor in many ways. Basically microprocessors are the devices which can process huge amount of data. A microprocessor can’t do anything on it own. Even to light a led a microprocessor needs minimum of a ROM, RAM, Latch, Address decoders, PORT controllers. But for the same application if you take a microcontroller you barely need a crystal and some capacitors.
This circuit known as the H-bridge (named for its topological similarity to the letter “H”) is commonly used to drive motors. In this circuit two of four transistors are selectively enabled to control current flow through a motor.
opposite pair of transistors (Transistor One and Transistor Three) is enabled, allowing current to flow through the motor. The other pair is disabled, and can be thought of as out of the circuit.
By determining which pair of transistors is enabled, current can be made to flow in either of the two directions through the motor. Because permanent-magnet motors reverse their direction of turn when the current flow is reversed, this circuit allows bidirectional control of the motor.
Object Detection
Detecting objects without whiskers doesn’t require anything as sophisticated as machine vision. Some robots use RADAR or SONAR (sometimes called SODAR when used in air instead of water). An even simpler system is to use infrared light to illuminate the robot’s path and determine when the light reflects off an object.The IR illuminators and detectors are readily available and inexpensive.
Infrared As Headlights
The infrared object detection system we’ll build on the Bot is like a car’s headlights in several respects. When the light from a car’s headlights reflects off obstacles, your eyes detect the obstacles and your brain processes them and makes your body guide the car accordingly. We will be using infrared LEDs for headlights. They emit infrared, and in some cases, the infrared reflects off objects and bounces back in the direction of the Bot. The eyes of the Bot are the infrared detectors. The infrared detectors send signals to the Microcontroller indicating whether or not they detect infrared reflected off an object. The brain of the Bot, the microcontroller makesdecisions and operates the motors based on this sensor input.
More about IR – Detector
The IR detectors have built-in optical filters that allow very little light except the 980 nm infrared that we want to detect onto its internal photodiode sensor. The infrared detector also has an electronic filter that only allows signals around 38.5 kHz to pass through. In other words, the detector is only looking for infrared that’s flashing on and off 38,500 times per second.
This prevents common IR interference sources such as sunlight and indoor lighting. Sunlight is DC interference (0 Hz), and indoor lighting tends to flash on and off at either 100 or 120 Hz, depending on the main power source in the region where you reside. Since 120 Hz is way outside the electronic filter’s 38.5 kHz band pass frequency, it is, for all practical purposes, completely ignored by the IR detectors.
As the receivers detects only modulated signals we need to have our IR LEDs modulated in 36 KHz to 40 KHz. We can use 555 timer to make this 40 KHz pulse. The simple circuit is given below.
Receiver
Pin 1 is ground
Pin 2 is Vcc
Pin 3 is Data Data Pin gives logic 0 when ever it detects IR Pulse.
MOTORS FOR LOCOMOTION.
Your car needs an engine to run, Even your can opener probly has a little motor inside to spin the can around. Your robot also needs something to make it run.
An actuator activated a mechanical device and is basically anything that causes movement on your robot. Motors, such as the motors that drive a robot, are the most common type of actuator. Motors come in several varieties such as the gear motor and the servo motor.Motors vary in power, speed , accuracy and power consumption. Some motors have shaft that rotate continuosly ; other types turn less than a complete rotation.
DC GEAR MOTOR:
The two types of motor’s that you are likely to use in robotic adventure are DC motors and RC servo motors. The most common motor for robotics is the DC gear motor, which works by gearing down a fast Dc motor to make the motor turn at a slower speed and give the motor a higher torque suitable for robot locomotion.
A dc gear motor is basically a regular DC motor with a special gear box attached to the output shaft . Your robot electrical drive circuitary can control the dc gear motor to rotate the wheels of your robot for locomotion.
You can get a DC motor without a gear head, but generally these are too fast ( around 15,000 RPM). For a robot to move at a reasonable rate you have to gear down a DC motor to about 30 to 80 RPM . When you gear down a DC motor, you get a slower speed and plenty of torque.
