Another robot project you can find here:

======================================

Introduction
Once I made this robot to get some study points while I was studying at the Technical High school in Rijswijk, the Netherlands. I made this in my limited free time, that is why it took me about a year to finish the project. A lot of the used techniques where new, so the research took a lot of the time, but is also the reason why this project had great value to me.

Target
Before I started developing the robot I made a few targets:

The TCS230 programmable color light-to-frequency converter combines configurable silicon photodiodes and a current-to-frequency converter on single monolithic CMOS integrated circuit. The output is a square wave (50% duty cycle) with frequency directly proportional to light intensity (irradiance). The full-scale output frequency can be scaled by one of three preset values via two control input pins. Digital inputs and digital output allow direct interface to a microcontroller or other logic circuitry. Output enable (OE) places the output in the high-impedance state for multiple-unit sharing of a microcontroller input line.

The light-to-frequency converter reads an 8 x 8 array of photodiodes. Sixteen photodiodes have blue filters, 16 photodiodes have green filters, 16 photodiodes have red filters, and 16 photodiodes are clear with no filters. The four types (colors) of photodiodes are interdigitated to minimize the effect of non-uniformity of incident irradiance. All 16 photodiodes of the same color are connected in parallel and which type of photodiode the device uses during operation is pin-selectable. Photodiodes are 120 mm x 120 mm in size and are on 144-mm centers.

Functional Block Diagram

Terminal Function

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.

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.

Left ————– Center ————— Right

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

Algorithm:

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.

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.

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.

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.