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Home: Welcome Make @ Home Projects ELECTRONICS ARDUINO AVR To play, press and hold the enter key. To stop, release the enter key. Various control sytems of SLIM-BOT without any Micro-controller To play, press and hold the enter key. To stop, release the enter key. AVR/ATTINY based various controls of SMALL ROBOT Learn @ Home Topics RESISTORs :: eBASICS :: To play, press and hold the enter key. To stop, release the enter key. Step-by-Step Learning ARDUINO Wishing Today is a Great Day to you by learning a new thing. This blog is developed for the students, hobbyists and enthusiasts . The main aim is self-learning of electronics, mechatronics step-by-step from basics to practical knowledge and Make-at-Home Projects. Hope this is the easiest way to learn and practice about electronics and mechatronics. Explained through CONCEPTS and PRACTICALS. i.e., a self learning School for Students and Enthusiasts, who wants to know and practice their own. ​ Click on the left-top for HOME PAGE , which is always available for easy navigation to the list of contents and also available through the menu. SEARCH by a keyword or phrase is also always available at the top of all the pages for convenience . ​ This website is BEST VIEWED in Desktop / Laptop / Tab, when comapared to mobile. ​ -: ALL THE BEST :- DREAM is not what you see in sleep, DREAM is something which doesn't let you sleep. – Dr. A.P.J Abdul Kalam Home: Works

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< Previous Next > Are you ever confused with the words AC and DC w.r.t. power supplies? If YES, then this page is for you. Just go through this page slowly and get an idea about DC power supply. Hay, there is NO EXAM afterwards. Nobody is behind you to check. Relax. If NO, just go through the highlighted words quickly. If you want to know about any highlighted word, then read slowly. Actually, the name DC (Direct Current ) is a misnomer. Some people may think, the power supply, which is available directly to home or office is Direct Current (DC) supply. NO. it is AC supply only. ​ If you consider the behavior of current flow in DC supply, its name shall be either Uni-directional Current supply or Non-Alternating Current supply. Okay, coming to our topic, DC supply is the power supply normally available from batteries, which have fixed positive and negative polarities, which will never change the direction of current flow. i.e., current flows from positive terminal to negative terminal. Where as the electrons flow from negative terminal to positive terminal (Current Electricity). OHM's law applies easily for DC power supplies. ​ i.e., V=I*R or I=V/R or R=V/I where, V=voltage, I=current flow and R=Resistance. ​ In electronic circuits, most of the times, we use DC power supply only. The DC power may be drawn from Batteries or rectified AC power supply. Many methods are available to convert AC power supply to DC power supply, out of which, Rectifier circuit and SMPS (Switching Mode Power Supply) are highly used. In general, DC power supplies have two or three types of voltage levels. Positive (+ve) Voltage level Negative (-ve) Voltage level Ground (gnd) level Positive Voltage is known for higher potential, where Negative Voltage is known for lower potential. Ground is the reference for both the Positive and Negative Voltage levels, which lies between the positive and negative voltages. Some times, like batteries and cells, where only two terminals are available from the power source, the ground and negative terminals are called by any name as ground or negative. Where as positive terminal is called as positive only. Actually, the voltage levels mentioned above are relative voltage levels to each other. If you observe the figure below, four cells are arranged in series, each with 1.5Volts DC. Each cell is marked as +ve and -ve on both the ends. You may observe that, by selecting the connections (CN1 to CN5) as ground reference, the Positive and Negative Voltages vary. For easy understanding, ground level may be the basic reference level marked as 0V and the voltage above the reference may be considered as positive voltage and the voltage below the reference may be considered as negative voltage. So, the total voltage difference between the positive to negative terminal may be considered as arthmatic summation of positive and negative voltages. eg: Total voltage between CN4 and CN1 in any case is 4.5V only. DC power supplies are highly used in electronic circuits and mechatronics projects. Most of the cases, the DC Desktop power supply is used, which is derived from mains power supply (after rectification and filtration) for testing, then connect to battery power supply for final project. AC to DC adaptors are used for economical and easy DC power supply for our projects or Battery packs, based on the required voltage and current. Now-a-days, rechargeable batteries, (like Lithium-Ion, LiPo, LiFePo4 etc.) are affordable for the electronics and mechatronics projects

< Previous Next > :STATIC ELECTRICITY: Static electricity is a stationary electric charge, produced due to an imbalance between positive and negative charges in an object or two near-by objects. Generally, this charge is build up on the surface of the object. To release the charge (or discharge) on the object, an electric path has to be created between positive and negative surfaces, through a circuit or an electric conductor (eg. copper wire). ​ Some materials that tend to gain or lose electrons easily, when comes in contact with other materials, like human hair, human skin, wool, cloth, silk, nylon, plastic sheet etc. Due to Static electricity, some times you feel mild electric shock and may feel nuisance. ​ Static Electricity has some advantages / applications , which are used in photo-copying machines for toner transfer, air pollution control systems using electro-static discharge concept, paint sprayers etc. ​ So, our hands (skin) may develop a mild static electricity when rubbing with glass or aluminum or silk cloth etc., which may be harmful (or damage) some sensitive ICs (Integrated Circuits). So, we should discharge static electricity from our hand before working with some ICs. We have to just touch (do not rub) to some metallic sheet to discharge Static electricity from our hand, before working on static electricity sensitive electronic components. Static electricity discharge pads are also available. ​ The main difference between the Static Electricity and Current Electricity are, In Static Electricity, the charges are at rest and in Current Electricity, the electrons are moving. The Static Electricity may be observed on the surface of insulator, where as Current Electricity means moving of electrons inside the conductor. Coulomb(s): Coulomb is unit of electrical charge and its symbol is C. A quantity of 1C is equal to approximately 6.24 x 10^18 electrons (its charge). (need not worry about these definitions. This is to just have an idea only) :CURRENT ELECTRICITY: Have you heard riddle “Which city has electrons” Answer is ELECTRICITY. The explanation below is to easily understand the term Electricity and its relative terms. In reality, understanding electricity and flow of electricity is a vast subject. In theory, Electricity means flow of electrons from higher potential to lower potential in conductors. You may be wondering, how electrons flow? What is conductor? . . . Do you remember basics of Quantum Physics? For quick recap, an atom consists of Protons(positively charged), Neutrons(no charge) and Electrons(negatively charged) particles. Protons and Neutrons occupy centre of the atom called neucleus and electons revolve around it. The quanity of Protons and Electrons always matches for an atom, so, the overall charge of the atom becomes ZERO. Most of the physics and chemistry depends on the behaviour of outer-most electrons and distance from the neuclies of the atom. Same with the electricity also. The (electric) Conductors, normally have one electron in the outer-most shell and/or loosly bound to the neuclies, i.e., very less energy is required to separate the outer-most electron from the atom. As the electron is negatively charged, it gets repelled by another negatively charged particle (electron) or gets attracted to positively charged particle (proton) of another atom. If an electron is separated from an atom, as the number of protons remains same, the atom becomes positively charged by 1, which is called cat-ion. These cat-ions have attraction towards negatively charged particles, i.e., electrons again to balance the overall charge of the atom. As per electron cloud theory, the loosely bound electrons form as electron cloud within the conductor (say metals) and move in haphazardly within the conductor. Electro Motive Force (e.m.f.): Coming to electricity, some (electrical) force is required to push the loosly-bound electron from the metal. As the electron moves out of the atom, it repels the loosly-bound electron of the nearest atom. The positively charged atom (cat-ion) attracts the next electron coming from the (electrical) force. This chain continues to create a flow of electrons. On the other side, the (electrical) force attracts and collects the flowing electrons. So, the (electrical) force must have positively charged elements to attract the electrons in the loop. The electrical force which makes the loop to create flow of electrons is called as Electro-Motive-Force (E.M.F.). So, an e.m.f. is required to generate flow of electrons in the conductor, pushes free electrons (loosly-bound electrons) on one side from its negative pole and attracts the free electrons on the other side, i.e. positive pole. In other words, electrons are negatively charged and carry their charge through the conductor, from one end to other end. So, electricity may be considered as moving the electrical charge through the conductor. The electrical charge cannot continue, unless the continuous contact of the conductor is available from beginning of the e.m.f. to receiving end of the e.m.f. i.e., the flow of charge will be disturbed, if the connectivity from any one of the ends of e.m.f. is lost. So, the continuation (or stoppage) of electricity may be controlled by a switch, which makes or breaks the continuity of the chain. So, e.m.f. is considered as the energy supplied to the conductor to have flow of electrons or electric charge, which is measured at end points of e.m.f. generator, like, battery, dynamo, solar cells etc. KEYWORDS: Potential Difference (P.D.) : Potential energy is the position possesed by electric particle due to location in an electric field. This may be compared as the position of an object on the earth w.r.t. distance from the centre of the earth, gravitational force on the object. Higher the altitutude means higher position and vice-versa. So, the difference between the potential energy of electrical particles in the circuit may be considered as Potential Difference. Voltage : Voltage is the energy required to move unit charge from one point to another, while electric charge is flowing. Voltage is measuring unit of Potential Difference between any two points or across a passive element of the electrical charge circuit. The sum of Voltages across all the passive elements in series is equal to the e.m.f. of the circuit. Volt(s) : Volt is the electrical unit of voltage and its symbol is V). One Volt is defined as energy consumption of one joule per electric charge of one coulomb. i.e., 1V = 1J/C. (don't worry or confuse about the definition right now). as per OHM's law, One volt is equal to current of 1 amp flows through resistance of 1 ohm: 1V = 1A ⋅ 1Ω ( formulated as V = I . R ) Current : The quantity of electrical charge moving between two points at any moment, due to e.m.f. is called current. The current may be considered as number of electrons flowing parallel to each other at an instant. It means, higher the electrons flowing across the conductor at a time is considered as higher current is flowing. Ampere(s) : Ampere is the electrical unit of Current and its symbol is A. One Ampere is defined as the current that flows with electric charge of one Coulomb per second. 1A = 1C/sec. (don't worry or confuse about the definition right now). as per OHM's law, One Ampere is equal to the current flows through resistance of 1 ohm across 1 volt: 1A = 1V / 1Ω ( formulated as I = V / R ) The fundamentals of Electricity is to be known before going through the next pages. The basics and keywords are frequently used in the future explanations. More details are available in the next pages, wherever applicable.

OMNI ROBO 00 Omni Wheel Intro to omni wheel Read More 01 Omni Robo Base Intro to Omni Robo - BASE Read More 02 Omni Robo Joystick Intro to joystick and control Read More

< Previous Next > In the AC (Alternating Current ) power supply, the direction of current flow changes periodically (for every fixed time length). For example, the current flow is in opposite direction, for every 1/100th second, for 50 Hz and 1/120th second, for 60 Hz power supplies. The power supply waveforms are sinusoidal in general and the model sinusoidal wave form (also called as sine wave) is shown here. Why AC ? Easy and convenient Power Transmission for long distances. For the AC power supply, the voltages may be easily stepped-up or stepped-down, also economically, using transformer, which requires complex circuits for DC power supply. AC generators are simpler in construction and maintenance than DC generators. Rotating magnetic field, which is required for motors, can be easily generated with AC power supply, compared to DC power supply. This simplifies construction of motors. Conversion process of AC to DC is simpler, which requires only rectifiers. Whereas conversion of DC to AC requires complex circuit(s). 110V or 220V ? Some countries distribute 110V AC with 60Hz, whereas other countries distribute 220V AC with 50Hz, as power supply to houses and industries. As the voltage increases, the severity of electric shock increases and more dangerous when touched to the live wire(s). Our body resistance reduces with skin wetness. So, most of the cold counties adopt 110VAC to reduce the risk of electric shock at higher voltage. For the same power requirement, for higher voltage, less current is consumed, whereas for lower voltage, higher current is consumed. The cross-section of wire requirement depends on quantity of current flow, which is directly proportional to it. So, for 110V power supply, the wire diameter is more (almost double cross-section), when compared to 220V power supply, for the same power requirement. What is RMS ? In the DC power supply, the Voltage or Current can be directly indicated, since the DC power supply is steady. Whereas in AC power supply, the Voltage or Current is periodically reversed. So, we can measure only Peak values, with special measuring equipment(s). So, in AC circuits, RMS values are used for measurement. The word RMS stands for Root Mean Square value. The RMS value shall be applied to Alternating Current or Alternating Voltage in AC power supplies only. For example, the RMS value of AC is equivalent to actual DC value. i.e., the power generated or power consumed using a DC power supply is equal to RMS AC power supply. So, RMS value is always less than the Peak value (Voltage or Current). Most of the electronic circuits does not require mains AC power supply as power source. Some circuits control the mains operated appliances, like motors, lighting system etc. Touching the mains supply is dangerous and lethal. So, care should be taken, while working on mains power supply.

Small Robot : 3 Joystick Control # . < < < Previous List All Next > > > . Introduction: Hey, using a joystick is more simple and easy to control the Small Robot. A readily available joystick module is used here to simplify the circuit. The joystick consists of two variable resistors fitted in perpendicular directions and a knob is provided to turn the variable resistors in required directions. The two variable resistors are spring loaded and positioned in mid-value of the resistance, by default. So, when the power supply (5VDC) is applied to the Joystick module at Vcc and Gnd pins, the outputs of the variable resistors shows 2.5V by default, at dX and dY pins. When, the joystick is moved in X-direction, one of the variable resistor moves up to its extreme value, i.e., minimum (0V) to maximum (5V). This voltage value is available at dX pin on the module. Similarly, if the joystick is moved in Y-direction, the other variable resistor moves up to its extreme value and the voltage is available at dY pin. A small push button is provided below the joystick knob, and its digital values of on/off status is available at SW pin on the module. This switch is not used in our joystick project. Here also, small 8 pin micro-controllers (ATTINY13) are used in Transmitter and Receiver circuits. The concept of Joystick control is almost similar to keyboard control explained earlier. The Joystick control system is almost similar to, Four button Keyboard control used earlier. The ADC values of dX (towards 0V and 5V) and dY (towards 0V and 5V) pins are converted to four digital values by the micro-controller, which matches to the four keyboard digital inputs. Both the Transmitter and Receiver boards, communicate through wireless transmitter and receiver modules. The joystick operation is encoded and sent by transmitter board, which is received and decoded by the receiver board, to control the Small Robot through the motor driver fixed on base frame. (refer Small-Robot Base Frame for motor control codes) Joystick Transmitter: The transmitter board receives ADC value, by moving the joystick in X and Y directions For the Joystick Transmitter board, a joystick module is used to control the direction of motion of Small Robot. By moving the joystick knob in forward, backward, right and left directions, the variable voltages available at dX and dY pins on the module are read by two ADC pins of micro-controller (ATTINY13). The two ADC values are converted to four bit digital data. Then, the four bits are sent through a pin as serial, in encoded form. (Refer Base Frame for four bit data) Any RF (Radio Frequency) Transmitter may be used, to transmit the Serial data, from the micro-controller to wireless radio wave. A 433 MHz RF transmitter module is used here for the purpose. A 7805 is used to convert 9V battery supply to 5VDC power supply for the circuit. Joystick Receiver: For the Joystick Receiver Board (which is similar to key board receiver), the serial data is received by the RF receiver module, and sent to the micro-controller (ATTINY13). The micro-controller decodes the received data, and converts to four bit parallel data. Then the four bits are sent to the base frame through the 6 pin connector, which in turn controls the movement of the Small Robot. The 5VDC power supply for Receiver board is derived from the Main board of Base Frame, through 6 pin connector. Download TX HEX file Download RX HEX file Contact for Source Code Download files from above link and remove .TXT extension. . < < < Previous Once Small Robot's Base Frame is made, then, various control systems for Small Robot are developed and available for selection, using 'Previous ' and 'Next ' buttons here. Next > > > .

Small Robot : 1 Base Frame # . < < < Previous List All Next > > > . Introduction The following are the General Requirements of a basic robot: 1. Chassis – 1no. 2. Motors – 2nos 3. Wheels – 2nos 4. Castor wheel – 1no 5. Battery and power supply circuit – 1 no. 6. Motor driver – 1no. 7. Controller Board (Microcontroller or other) – 1no (minimum) 8. Display / status indicators – as per requirement 9. Sensors / other input devices – as per requirement 10. Programmer (to load code to microcontroller) – 1no. 11. Software(s) – as per requirement. 12. logic development skills. Out of above listed 12 points, first 6 points are common and hardly change the items. These are mainly hardware items and does not require any software skills. Same robot can be modified to required configuration by changing micro-controller / sensors / inputs / displays / software / logic. The Small Robot is simple in construction, compact design and have mainly two parts. The first part , Palm Robot – Base Frame, contains the 1 to 6 items of the above list and second part, Small Robot – Control, contains the 7 to 12 items of the above list. By using Small Robot Base Frame, time is saved to develop logic using various micro-controller(s) and software(s). The Small Robot control systems are designed/developed using AVR microcontrollers here. But, the same logic can be developed using PIC or other microcontroller(s) and the output of the logic can be used to control the Small Robot Base Frame. About Base Frame: The Small Robot – Base Frame, contains two B.O. motors with 200 rpm are attached to a chassis on either side and two suitable wheels are mounted on it. A castor wheel with bracket is fixed on front side of the chassis. A 7.4V Li-ion battery is placed between two B.O.motors. 4 or 6 nos of long bolts may be suitably arranged on top of the chassis to hold circuit boards. A circuit board, called Main Board, with motor driver IC (L293D) and two separate 5VDC regulated power supplies are fixed on top of the chassis, which hardly covers half of the chassis and makes room for adding microcontroller board of one’s choice. One of the 5VDC supply may be used for microcontroller board and sensors. The other 5VDC supply or 7.4VDC from the battery may be used for motors by selecting jumper J1. Due to separate 5VDC supplies, the microcontroller board have least impact of voltage fluctuations due to motors. A six pin berg strip is available on the Main Board. Out of 6 pins 2 pins are Ground and 5VDC supply for Microcontroller board and remaining 4 pins are data input pins (D3, D2, D1, D0) for motor control. The logic for control of motors are as follows: Circuit Diagram of Main Board A PCB is required to assemble all the components shown below in the circuit diagram. For Small Robot, the PCB is fitted on the top of the chassis, where as motors (with wheels), castor wheel and battery is fitted below the chassis. Good Day to you Download 4 bit code Contact for Source Code Making Base Frame is mandatory to add various types of controls. . < < < Previous Once Small Robot's Base Frame is made, then, various control systems for Small Robot are developed and available for selection, using 'Previous ' and 'Next ' buttons here. Next > > > .

Small Robot : 8 Edge Detector # . < < < Previous List All Next > > > . Introduction: An Edge Detector is also a self controlled Robot, which will recognize edge of a flat surface (like table) and moves within the flat surface, without falling down. Two IR sensor modules are used on front side of the Small Robot to recognize the edge of a surface. The two IR sensors on both sides, read the presence of the flat surface and the signal is sent to the micro-controller (ATTINY84) accordingly. The signals received from the IR sensor modules are analyzed by the ATTINY84, then Small Robot moves back a little and takes right or left turn accordingly, based on the 4 bit motor control data, through the motor driver (L293D) on base board. (refer Small Robot Base Frame for motor control codes). The concept of Edge Detector Robot is to avoid falling from edge of any flat surface. The Edge Detector searches for the reflection of IR light from the bottom surface, then moves forward or takes turn accordingly, to avoid falling from the flat surface. Here, the Small Robot is programmed to take a right or left turn, when the IR light reflection is absent, depending on the IR sensor module signal, else moves forward continuously. About Edge Sensing: The Edge Detector uses two IR (Infra-red) sensor modules (readily available) to read the presence of bottom surface. The IR sensor module consists of an IR emitting LED , an IR sensor LED, indication LEDs and an OP-AMP IC (mostly LM358), with a trimpot for sensitivity adjustment. When the module is connected to 5VDC power supply, the IR LED emits IR light on the bottom surface. The IR light reflected from the bottom surface and falls on an IR sensor (in LED shape), placed near to the IR LED. The op-amp based circuit, reads the change in the internal resistance of the IR sensor, due to IR light falling on it, and status is displayed by glowing indicator LED (red). When the reflected IR light is absent, then the indicator LED does not glow (status off). A three pin connector is available on IR sensor board, out of which two are for 5VDC and ground. The third pin is signal OUT pin. So, when the surface below the IR sensor is present, then a HIGH (1) signal is generated at OUT pin. Similarly, when the surface is absent, then a LOW (zero) signal is generated at OUT pin. The LED indicator glows accordingly. After assembly, adjust the trimpots on the IR sensor boards, independently, for their sensitivity to surface reflection. The arrangement of two numbers of IR sensor boards are show below. Both the IR sensor boards are to be fitted on front side of the Small Robot, on either side. The distance between the two extreme IR sensors shall be kept more than the overall width of the Small Robot. Working of Edge Detector: Making of Small Robot as Edge Detector is simple and easy. A simple bracket is required to position two IR sensor boards on the front side of the Edge Detector. A PCB with micro-controller ATTINY84 is used as control system for the Edge Detector, based on the digital signals (at OUT pins) available from two IR sensor boards. The digital signals from the IR sensor boards are read as, two digital inputs by the micro-controller. Then, the programmed logic makes the Small Robot to make a right or left turn, if digital logic goes LOW (0), else moves forward. To avoid falling on immediate turning, the Small Robot moves little backward, then takes turn accordingly. A button switch, SW1 on control board, is useful to start the Edge Detector, after switching ON the power supply to the Control Board. The complete circuit diagram of Control Board with ATTINY84, is available below. Use jumper wires to connect two OUT pins from Sensor Board to Control board. Enjoy DIY Download ED HEX file Contact for Source Code Download file from above link and remove .TXT extension. . < < < Previous Once Small Robot's Base Frame is made, then, various control systems for Small Robot are developed and available for selection, using 'Previous ' and 'Next ' buttons here. Next > > > .

Small Robot : 6 Line Follower # . < < < Previous List All Next > > > . Introduction A Line Follower is self controlled Robot, which follows a thick line. Many types of sensors are used to read the line. The Small Robot uses IR (Infra-Red) sensors, to read the line. Five pairs of IR LEDs and IR sensors (shaped as LED) are used here to read the Line. All the five IR sensing pairs are arranged in a row, perpendicular to the line path. The Small Robot always try to position symmetrical to the line, by following the middle IR sensing pair (out of 5 IR pairs in a row). To have more input pins (at least 5 inputs are required for IR sensors), in small size, ATTNY84 micro-controller is selected, which have 14 pins. Out of 14 pins, five pins are used for sensing the line and four pins are required to control the two motors, through the motor driver (L293D). (refer Small Robot Base Frame for motor control codes). In general Line Followers are set to follow the line and complete target distance as soon as possible without leaving the line. The programming is either target for fast line follower, with smooth curves, or complicated line follower with various types of obstacles. The Small Robot is programmed here to follower various line types, like, sharp bends, sharp turns, sharp curves, crossings, gaps in lines, zig-zag lines, double lines, stop identification etc. A model path used to test the Small Robot is shown below, having various line shapes. About Line Sensing: Most of the Line Followers use IR (Infra-red) sensing system to read the presence of line. An IR LED emits IR light on the bottom surface (where the line is drawn). The IR light reflects from the surface and falls on an IR sensor (in LED shape), placed near to the IR LED. The IR sensor is connected in reverse biased, which varies its internal resistance, depending on the brightness of reflected IR light. The internal resistance of the IR sensor decreases with increase in falling IR light. So, when the surface below the IR sensor is white, more reflected light falls on the IR sensor, which makes least internal resistance. Similarly, if the surface is black, least light reflects on the IR sensor, which makes highest internal resistance. Due to change in the resistance of IR sensor, the voltage at the junction of the IR sensor and fixed resistance varies, which are connected in series with power supply and ground. A typical IR LED + IR sensor pair arrangement with the circuit diagram is shown below. Total 5 such IR sensing pairs are required for Small Robot, and soldered on a PCB, then fixed in front of the Small Robot. All the IR LEDs and IR sensors are 3 mm size. Maintain the gap between. the two successive IR sensors should be just less than the line width. The IR sensor PCB, with 5 IR pairs, shall be fitted in front of the Small Robot, with a clearance adjustment arrangement (from surface) , to adjust the sensitivity with black and white surfaces. Working of Line Follower: Making of Small Robot as Line Follower is simple and easy. One PCB is required for IR sensing board, with 5 pairs of IR LEDs and IR sensors explained above. Another PCB with micro-controller ATTINY84 is used as control system for the Line Follower based on the varying voltages obtained from five IR senors. The varying voltages from the IR sensor board are read as five digital inputs by the micro-controller. Then, the programmed logic makes the Small Robot to follow middle IR sensor. In case, the Small Robot reads the line from any other IR sensors, the required output code is sent through the four motor control pins, to turn the Small Robot accordingly, else Small Robot moves in straight line. In case of sharp turns, gaps, crossings, junctions or stop blocks etc., the Small Robot moves little further and then takes necessary movement accordingly. The complete circuit diagram of Control Board with ATTINY84, is available below. Use jumper wires to connect S1…S5 pins from Sensor Board to Control board consecutively. The shorting jumper J1 is provided to select the line colour as BLACK or WHITE. Either Red or Yellow LED glows by selecting the shorting jumper position, for Black or White line. A button switch, SW1, is useful to start the Line Follower, after switching ON the power supply to the Control Board. All the Best Download LF HEX file Contact for Source Code Download file from above link and remove .TXT extension. . < < < Previous Once Small Robot's Base Frame is made, then, various control systems for Small Robot are developed and available for selection, using 'Previous ' and 'Next ' buttons here. Next > > > .

Small Robot : 7 Path Follower # . < < < Previous List All Next > > > . Introduction: A Path Follower is self controlled Robot, which follows in a path, which is a wide white or black line. The width of the path is generally more than the width of the Robot. Like Line Follower, here also, many types of sensors may be used to read the path. The Small Robot uses IR (Infra-Red) sensors, to read the path. Four pairs of IR LEDs and IR sensors (shaped as LED) are used here to read the Path. All the four IR sensing pairs are arranged in a row, perpendicular to the path, two on each side of the Small Robot. The Small Robot always try to position within the path, by following the edge of the path. To read four input pins for IR sensors, ATTNY84 micro-controller is selected, which have 14 pins. Out of 14 pins, four pins are used for sensing the line and four pins are required to control the two motors, through the motor driver (L293D). (refer Small Robot Base Frame for motor control codes). In general, Path Followers are used in industries for material handling. The robot moves within the two lines earmarked for its movement. The programming is to move the Robot within two thick lines, which forms as a path, which may have sharp and smooth curves. The Small Robot is programmed here to follow various path shapes, like sharp bends, sharp turns, sharp curves etc. The coding may be modified for individuals requirement. A model path used to test the Small Robot is shown below, having various line shapes. About Path Sensing: The Path Follower uses IR (Infra-red) sensing system to read the presence of Path. An IR LED emits IR light on the bottom surface. The IR light reflects from the surface and falls on an IR sensor (in LED shape), placed near to the IR LED. The IR sensor is connected in reverse biased, which varies its internal resistance, depending on the brightness of reflected IR light. The internal resistance of the IR sensor decreases with increase in falling IR light. So, when the surface below the IR sensor is white, more reflected light falls on the IR sensor, which makes least internal resistance. Similarly, if the surface is black, least light reflects on the IR sensor, which makes highest internal resistance. Due to change in the resistance of IR sensor, the voltage at the junction of the IR sensor and fixed resistance varies, which are connected in series with power supply and ground. A typical IR LED + IR sensor pair arrangement with the circuit diagram is shown below. Total four such IR sensing pairs are required for Path Following Small Robot, and soldered on a PCB, then fixed in front of the Small Robot. All the IR LEDs and IR sensors are 3 mm size. Maintain the gap between. the two successive IR sensors at each extreme end should be just less than the line width of the path. The distance between the mid of the two extreme IR sensors shall be approximately equal to the width of the path. So, that, the Path Follower tries to keep the itself within the path. The IR sensor PCB, with 4 IR pairs, shall be fitted in front of the Small Robot, as shown below, with a clearance adjustment arrangement (from surface) , to adjust the sensitivity with black and white surfaces. Working of Path Follower: Making of Small Robot as Path Follower is simple and easy. One PCB is required for IR sensing board, with 4 pairs of IR LEDs and IR sensors explained above. Another PCB with micro-controller ATTINY84 is used as control system for the Path Follower based on the varying voltages obtained from four IR sensors. The varying voltages from the IR sensor board are read as four digital inputs by the micro-controller. Then, the programmed logic makes the Small Robot to follow middle two IR sensor. In case, the Small Robot reads that, any IR sensor is out of path, the required output code is sent through the four motor control pins, to turn the Small Robot accordingly, else Small Robot moves in straight path. Similarly, in case of sharp turns, smooth turns, the Small Robot turns accordingly. The complete circuit diagram of Control Board with ATTINY84, is available below. Use jumper wires to connect S1, S2, S3 & S4 pins from Sensor Board to Control board consecutively. The shorting jumper, J1 is provided to select the path colour as BLACK or WHITE. Either Red or Yellow LED glows by selecting the shorting jumper position, for White or Black path. A button switch, SW1 on control board, is useful to start the Path Follower, after switching ON the power supply to the Control Board. Best of Luck Download PF HEX file Contact for Source Code Download file from above link and remove .TXT extension. . < < < Previous Once Small Robot's Base Frame is made, then, various control systems for Small Robot are developed and available for selection, using 'Previous ' and 'Next ' buttons here. Next > > > .

Small Robot : 2 Keypad Control # . < < < Previous List All Next > > > . Introduction To control Small Robot, a simple and easy concept is explained here. Four buttons are used to control the Small Robot, in all the four directions. To make the Robot control small and simple, ATTINT13 (8 pin micro controller) is used for both transmitter and receiver boards. A Transmitter board, is designed with a micro-controller (ATTINY13) , which receives four inputs from the small buttons and converts to 4 bit data. Then sends the 4 bit data as serial data. The serial data is sent through a wireless transmitter module. Similarly, Receiver board, is also designed to receive the serial data, through a wireless receiver module. Then, the micro-controller (ATTINY13) decodes the serial data, to four bit parallel data, used as input to motor driver IC (L293D). Thus, motor driver controls the two motors of the Small Robot, for required movement, in all the directions, depending on the keyboard input(s). Keypad Transmitter: For the Keypad Transmitter board, four keys are used to control the direction of motion of Small Robot. Every two keys have parallel connection with two voltage divider resistances. So, by default, the micro-controller receives, mid voltage of power supply (i.e., 2.5V), as input. Two such inputs are used for four input buttons. Both the inputs are connected to the micro-controller's ADC (Analog-to-Digital Converter) pins. So, when no button is pressed, the micro-controller reads mid value of ADC from both the pins. When, any input button is pressed, the ADC value is set as, either maximum or minimum, depending on the button press. So, the micro-controller always checks the ADC input voltage and converts the ADC value to four bit digital data. Then, the four bits are sent through a pin as serial in encoded form. (Refer Base Frame for four bit data) Any RF (Radio Frequency) Transmitter may be used, to transmit the Serial data, from the micro-controller to wireless radio wave. A 433 MHz RF transmitter module is used here for the purpose. A 7805 is used to convert 9V battery supply to 5VDC power supply for the circuit. Keypad Receiver: For the Keypad Receiver Board, the serial data is received by the RF receiver module, and sent to the micro-controller (ATTINY13). The micro-controller decodes the received data, and converts to four bit parallel data. Then the four bits are sent to the base frame through the 6 pin connector, which in turn controls the movement of the Small Robot. The 5VDC power supply for Receiver board is derived from the Main board of Base Frame, through 6 pin connector. Download TX HEX file Download RX HEX file Contact for Source Code Download files from above link and remove .TXT extension. . < < < Previous Once Small Robot's Base Frame is made, then, various control systems for Small Robot are developed and available for selection, using 'Previous ' and 'Next ' buttons here. Next > > > .