AVR Line Following Robot Tutorial

March 21st, 2008 by Robot Technology | 3 Comments | Filed in Electronics, Microcontroller, Programming, Robotics Tutorial, Sensors

Block Diagram

The robot uses IR sensors to sense the line, an array of 8 IR LEDs< (Tx) and sensors (Rx), facing the ground has been used in this setup. The output of the sensors is an analog signal which depends on the amount of light reflected back, this analog signal is given to the comparator to produce 0s and 1s which are then fed to the µC.

L4L3L2L1R1R2R3R4

Left ———— Center ————- Right

Sensor Array

Starting from the center, the sensors on the left are named L1, L2, L3, L4 and those on the right are named R1, R2, R3, R4.
Let us assume that when a sensor is on the line it reads 0 and when it is off the line it reads 1

The µC decides the next move so as to position the robot such that L1 and R1 both read 0 and the rest read 1.

L4L3

L2

L1

R1

R2

R3

R4

Left ————– Center ————— Right

Desired State L1=R1=0, and Rest=1

Algorithm:

Tags: , , , ,

UV Tron – Fire Detection Sensor

March 21st, 2008 by Robot Technology | 4 Comments | Filed in Electronics, Robotics Tutorial, Sensors

uvtron sensor

The object of the fire detection is to navigate the robots through a maze of walls and look into the rooms and see if there is a fire. Using a UV sensor, a flame the size of a single candle can be seen 5 meters away. The Trekker utilizes a Hamamatsu UV sensor that is mounted onto the Trekker sweeping sensor brackets. The Trekker scans the area and finds an open flame.The Hamamatsu UV TRON Flame Detector is lightweight, has low current consumption, and operates as high sensitivity UV Sensor. The UV TRON is an ultraviolet detector that makes use of the photoelectric effect of metal combined with the gas multiplication effect. It has a narrow spectral sensitivity of 185 to 260 nm. Thus it is solar blind, being completely insensitive to visible light. Unlike semiconductor detectors, it does not require optical Visible-cut filters, thus making it easy to use.

uv tron flame detector

The driver for the UV TRON is operated by applying DC low voltage and outputs a high-voltage power supply. It also contains a signal processing circuit on the same printed circuit board. Since background discharges of the UV TRON caused by natural excitation lights (such as a cosmic ray, scattered sunlight, etc.) can be cancelled in the signal processing circuit, the output signals from the C3704 series can be used without errors.UV TRON Flame detector is small, but has a wide angular sensitivity (directivity) and can reliably and quickly detect weak ultraviolet radiation emitted from a flame due to use of the metal plate cathode (e.g. it can detect the flame of a cigarette lighter at a distance of more than 5 m.). The Flame detector is well suited for use in flame detectors and fire alarms, and also in detection of invisible discharge phenomena such as corona discharge of high-voltage transmission lines. To minimize the area the sensor sees the flame, a field of view mask can be used. The shields are useful when you are trying to locate the location of the flame.

Tags: , , , , , ,

Line Follower Robot Tutorial

March 20th, 2008 by Robot Technology | 75 Comments | Filed in Electronics, Mechanics, Microcontroller, Programming, Robotics Tutorial, Sensors, Software

Line Follower ROBOT

Plermjai Inchuay, plermjai@loxinfo.co.th

Award winner from VingPeaw Competition 2543, the robot built with 2051, L293D, and four IR sensors. Simple circuit and platform, quick tracking and easy-understand program using C language.

Line Follower Robot design

I designed my robot, which use two motors control rear wheels and the single front wheel is free. It has 4-infrared sensors on the bottom for detect black tracking tape, when the sensors detected black color, output of comparator, LM324 is low logic and the other the output is high. Microcontroller AT89C2051 and H-Bridge driver L293D were used to control direction and speed of motor.

line follower robot circuit

Tags: , , , , , , , , , , , , ,

Photo Detectors

March 20th, 2008 by Robot Technology | No Comments | Filed in Robotics Articles, Sensors

Photosensors or photodetectors are sensors of light or other electromagnetic energy. There are several varieties:

photo sensor

Most optical detectors are quantum devices in which an individual photon produces a discrete effect.

  • Chemical detectors, such as photographic plates, in which a silver halide molecule is split into an atom of metallic silver and a halogen atom. The photographic developer causes adjacent molecules to split similarly.
  • Photoresistors or Light Dependent Resistors (LDR) which change resistance according to light intensity
  • Photovoltaic cells or solar cells which produce a voltage and supply an electric current when illuminated
  • Photodiodes which can operate in photovoltaic mode or photoconductive mode
  • Photomultiplier tubes containing a photocathode which emits electrons when illuminated, the electrons are then amplified by a chain of dynodes.
  • Phototubes containing a photocathode which emits electrons when illuminated and in general behaves as a photoresistor.

Tags: , ,

Line Follower Sensor

March 20th, 2008 by Robot Technology | 4 Comments | Filed in Sensors

The circuit diagram for the Line Follow Sensor board is shown below:

The board is connected directly to the Light IO board via PL4.

This circuit is very simple. +5V is applied via PL4 pin 4 to the circuit, and 0V is connected to pin 1 of PL4. When power has been applied, which is controlled by the processor1 board, Infra-Red LEDs D1 and D2 will emit Infra-Red light. If you

Tags: , , , , , , , , , , , , ,

A D V E R T I S E M E N T