H-Bridge is an electronic circuit which will control the mechanical of the robot.
The H-Bridge is the link between digital circuitry and mechanical action. The computer sends out binary commands, and high powered actuators do stuff. Most often H-bridges are used to control rotational direction of DC motors. And unless you buy a potentially expensive motor-driver, you need an H-bridge to control any robot with a motor.
This is a quickly sketched H-Bridge circuit with supporting circuitry.
First lets talk about what a transistor is. These nifty chips revolutionized the electronics industry and you would be hardpressed to find something electronic that does not have at least a few thousand of these in them. So what do they do? They can control a flow of electrons by applying a voltage to them. The plumbing equivalent would be a water valve. By rotating the valve, a very large flow of water can easily be controlled.
Sound activation or tone detector usually used for robot start activation. When a sound received by microphone in tone detector, the robot will start to move.
I’ve collected some schematic diagrams of sound activation as follow:
Sound Activation schematic 1
Sound Activation schematic 2
h bridge schematics
DC Motors which need high current and high voltage usually give high velocity and high torque. For small robots like line follower robot or fire fighting robot, I think IC motor driver L298 (up to 2A total current) is better choice. While for large and heavy robot, you need high current DC motors also H-Bridge suit to your DC motor.
This article sould be useful for you to build high
The L297 integrates all the control circuitry required to control bipolar and unipolar stepper motors. Used with a dual bridge driver such as the L298N forms a complete microprocessor-to-bipolar stepper motor interface. Unipolar stepper motor can be driven with an L297 plus a quad darlington array. This note describes the operation of the circuit and shows how it is used.
Download Sharp GP2D12 Analog Distance Sensor Manual and Tutorial
SharpGP2D12Snrs.pdf
Download ping parallax ultrasonic distance sensor datasheet, schematic and program code sample:
PIC18CXXX/PIC16CXXX DC Servomotor Application Note:
Download the tutorial:
DC servomotor application of PIC.pdf
Another tutorial how to get start with the AVR microcontroller:
Just download the file here:
getting_started_with_the_AVR.pdf
Why would you want to interface the Keyboard? The IBM keyboard can be a cheap alternative to a keyboard on a Microprocessor development system. Or maybe you want a remote terminal, just couple it with a LCD Module.
Maybe you have a RS-232 Barcode Scanner or other input devices, which you want to use with existing software which only allows you to key in numbers or letters. You could design yourself a little box to convert RS-232 into a Keyboard Transmission, making it transparent to the software.
An interfacing example is given showing the keyboard’s protocols in action. This interfacing example uses a 89s51 MCU to decode an IBM AT keyboard and output the ASCII equivalent of the key pressed at 9600 BPS.
Note that this page only deals with AT Keyboards. If you have any XT keyboards, you wish to interface, consider placing them in a museum. We will not deal with this type of keyboard in this document. XT Keyboards use a different protocol compared to the AT, thus code contained on this page will be incompatible.
PC Keyboard Theory
The IBM keyboard you most probably have sitting in front of you, sends scan codes to your computer. The scan codes tell your Keyboard Bios, what keys you have pressed or released. Take for example the ‘A’ Key. The ‘A’ key has a scan code of 1C (hex). When you press the ‘A’ key, your keyboard will send 1C down it’s serial line. If you are still holding it down, for longer than it’s typematic delay, another 1C will be sent. This keeps occurring until another key has been pressed, or if the ‘A’ key has been released.
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.
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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.
