Hello i have fear in my mind, first time i am going to use relay in my project. In this project we will interface a relay with pic microcontroller pic16f877a. You should also have a look at relay interfacing with microcontroller using uln2003. Interfacing a relay with microcontroller electronics. This attempted to provide a comprehensive introduction to the subject via a single type of microcontroller, which is essentially a complete computer on a chip. The output port pins of microcontrollers can can only source few milli amperes of current, so they cannot be directly used to energize relays. May 10, 20 a relay is activated by energizing its coil. Circuit diagram for relay module interfacing with pic16f877a microcontroller is shown below. Relay module interfacing with pic16f877a microcontroller how to interface ac load through relay with pic microcontroller with programming. Interfacing relay with pic microcontroller using transistor.
If possible, the relay should be powered by a separate power supply to enable a connection of relays requiring a different voltage like for example a 12v relay which is different form the 5v supplied to the microcontroller. Interfacing relay to microcontroller relays are devices which allow low power circuits to switch a relatively high currentvoltage onoff. Interfacing a relay with pic microcontroller mikroc. A relay can be used to switch high power devices from a. Introduction to the arduino microcontroller handson research in complex systems shanghai jiao tong university june 17 29, 2012 instructor. Singlesupply incircuit serial programming enable bit rb3pgm pin has. Arduino relay module tutorial microcontroller tutorials. Interfacing hcsr04 ultrasonic rangefinder with pic 16f877a microcontroller.
Whenever 8051 microcontroller is turned on initially the controller is in reset state and all the controller pins are high which would result in turning on the relay every time power is turned on or if there is a power fluctuation. Relay interfacing with pic16f877a friendly free download as pdf file. Apr 24, 2018 interfacing pic microcontroller with st7735r spi tft mikroc projects this post shows how to use mikroc library for st7735r tft with pic16f887 microcontroller where hardware spi module of the pic16f887 is used in this example. Pic microcontrollers, for beginners too online, author. Ssrs make interfacing with ac voltage really, really simple. If desired, the relay can be powered by a separate power supply, so, for. Relay provides isolation between two voltage levels and it is generally use to control ac appliances. Current flows from the 12v input to the relay and then to the ground via the transistors collector pin. In this tutorial im connecting one relay in port b. See more ideas about pic microcontroller, microcontrollers, pics.
A relay is commonly used to interface a lowcurrent circuit to a highercurrent circuit. To understand how microcontroller works as a multifunctional relay it is necessary to know about microcontroller working, functions and its applications. Example for interfacing a relay board with low cost 40 pin avr development board to control a 220v ac load like a bulb. As you can see an npn transistor bc547 is being used to control the relay. Relay module interfacing with pic16f877a microcontroller ac load. A pic controller integrates all type of advanced interfacing ports and memory modules. Electromechanical relays interfacing circuits with. Introduction this article is meant for beginners in the field of microcontrollers. Transistor is wired as a switch which carries the current required for operation of the relay. See the block diagram of driver circuit which i used in my project.
Relay interfacing with microcontroller using uln2003a the. Electrical engineering stack exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. In this project, pic microcontroller will be used tocontrol and operate the tripping coil in circuit breaker. Interfacing relay with 8051 slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. But microcontroller output pint can provide maximum current up to 12ma. A pic microcontroller is a single integrated circuit small enough to fit in the palm of a hand. After introducing the pic16f877 and its programming, this book covers the fundamental techniques and advanced level techniques of embedded systems programming in a general sense. The pic was the first widely available device to use. The lcd module interface with a microcontroller is simple and it is a primitive means of adding a visual appeal to your embedded application. There are two basic types of lcd modules in the market they are, character lcd and graphics lcd. The transistor will be in off state when the when the pin p2. In this project report description of inputoutput interfacing of microcontroller and the program, which is. Jun 07, 2011 interfacing relay with 8051 slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising.
Relay is a mechanical device to control high voltage, high current appliances on or off from lower voltage levels. Programming with pic microcontroller research design lab. The steps involved in interfacing an lcd with 8051 1. In simple words, we attach any pin of the pic with one pin of relay coil and make the other pin to ground. This microcontroller controlled the relay with so efficiently and intelligently.
Microcontroller may stop working by the negative voltages produced in the relay due to its back emf. Arduino relay tutorial 5v relay arduino interfacing. An intro to relays basically, a relay is an electromagnetic switch. Nov 23, 2014 interfacing hcsr04 ultrasonic rangefinder with pic 16f877a microcontroller dht11 humidity sensor interface with pic16f877a p10 rg led display interface with stm32f030f4 32bit mcu. The input is taken from the microcontroller pins and the output corresponding to each input is given to the 5 relays on the output. It is therefore connected to ouput pins of the microcontroller and used to turn onoff highpower devices such as motors, transformers, heaters, bulbs, antenna systems etc. The pic microcontroller from microchip is one the famous and most used microcontrollers.
May 21, 2016 automatic street light control using 8051 micro controller,keil ide and proteus simulation duration. From the above equation the value of r3 comes out to be 5. Uln2803 is used as a driver for port io lines, drivers output connected to relay modules. Arduino relay tutorial 5v relay arduino interfacing maxphi lab. Define function for sending command to the lcd using 8051 a. If possible, the relay can be powered by a separate power supply to enable connection of relays requiring a different voltage like for example a 12v. Both microcontrollers and microprocessors are complex sequential digitalcircuits meant to carry out job according to the program instructions.
In this part we will cover their interface with microcontrollers. In this project we will interface a relay with pic microcontroller. I have connected a push button with pic microcontroller which will be used to turn on and turn off relay module. A relay can be easily interfaced with microcontroller using a transistor as shown below. In this arduino relay tutorial, i will show you how to use a relay with microcontrollers. How to interface relay with pic16f877a pic development board.
Interfacing of relay with microcontroller aticleworld. Microcontroller is a programmable digital processor with necessaryperipherals. How to control a relay from pic microcontroller circuit. As such, its very useful in controlling appliances and other mainspowered devices using microcontrollers. Interfacing the uln2803 darlington driver ic to pic microcontroller 9. In this tutorial we will discuss the interfacing of the relay board with 40 pin avr development board. Actually, we just control the coil portion of relay, so we send the signal to the relay coil. If possible, the relay should be powered by a separate power supply to enable a connection of relays requiring a different voltage like for example a 12v relay which is. Interfacing devices with pic microcontroller studentcompanion. To interface relay with microcontroller we need a driver circuit to drive the power to relay. To solve this and interface a relay with any microcontroller. To resolve this problem relay driver circuits are used between microcontroller and relay. The below list of pic tutorials and pic projects helps you to learn pic series of microcontrollers from very basic level to advanced applications.
Microcontroller interfacing circuits revolution revolution education ltd. Relay interfacing with microcontroller 8051 microcontroller. Relay is a combination of the mechanical switch and an electromagnet, it prefers when we want to control a device or machine using the low strength signal. If a relay is in normally close nc contact, there is a closed circuit until a relay is energized. Pic microcontrollers can be used as the brain to control a large variety of products. Relay interfacing with arduino august 31, 2017 february 9, 2018 by admin 1 comment our main aim in this tutorial is how to control an ac appliance using arduino. Nov 02, 2012 relay interfacing with microcontroller. Is there anything else i havent considered like excessive heat when using the mosfet. Relay interfacing with pic16f877a friendly pic microcontroller. If you want to know more about relay driver circuit uln2003, relay working and relay interfacing with arduino check these articles. Harness the power of the pic microcontroller unit with practical, commonsense instruction from an engineering expert.
How to control a relay from pic microcontroller circuit diagram simply you can control a relay through pic microcontroller. This current switches on the relay which in turn switches on the ac load the bulb the diode d1 1n4007 is used as a flyback diode. From mechanical to solid state relays, there are various type of relays are. Other types of relays also used know as solid state relay in which dc voltage used as input. Relay interfacing with pic microcontroller pic16f877a circuit digest. Microcontroller boardscontrol the relay operations by using pic16f18f slicker board. When microcontroller makes the output line high binary 1, the transistor is switched on. Interfacing relay to microcontroller dna technology. Here i used diode d11n4148ws, resistor r1 1k, transistor t1 bc547, 12 v power supply and 6v relay.
Interfacing relay with pic microcontroller youtube. The general sense esp techniques can be applied to any microcontroller. If you continue browsing the site, you agree to the use of cookies on this website. The kit supports in system programming isp which is done through usb port. From mechanical to solid state relays, there are various type of relays are available in. When the coil is energized, the switch closes, connecting the two contacts together. These controllers are more advanced than normal microcontroller like 8051. Interfacing lcd module with microcontroller embedjournal. These microcontrollers are widely used in modern electronics applications.
Feb 05, 2014 to control our high voltage device like home appliance by pic microcontroller, we have to have clear idea on interfacing relay with pic microcontroller. Should i use a fet rather than the 2222 bjt if i want to use pwm. Relay module interfacing with pic16f877a microcontroller. In order to control devices, it is necessary to interface or connect them to the pic microcontroller. The microcontroller will switch on the transistor which in turn will switch on the relay, anything connected to the contacts of the relay can thus be switched on or off. As the pic microcontroller operates at 5v a potential divider formed from resistors must be used to reduce the pic microcontroller output signal to 1. So by using relay switch we easily turn on or off any high voltage device by microcontroller. In the last two tutorials we learnt about what are relays and how they work. When the pin rb7 of the pic microcontroller goes high, the transistor bc547 turns on and current. When rb5 port of pic become high the relay will operate.
When i measure the output across the diode without the relay i have 12v when the pic. Because of its reliability it is commonly preferred by embedded engineers for industrial applications. See the block diagram below to how we turn on or off a 230 volt ac bulb by micro controller. This post shows how to use mikroc library for st7735r 1. This may also damage the device connected to relay so as. The pic tutorial free pic books pic microcontroller.
See a simple circuit for controlling a single relay with pic 16f628. A relays is an electrical switch that opens and closes under control of another electrical circuit. Character lcds are the some of the cheapest means lcd displays available today. Relay i am using here is of 12v, i am using this one because its mostly used in projects. Relay interfacing with pic microcontroller pic16f877a. In this tutorial, we will learn about the interfacing of the relay relay connection with microcontroller and learn how to control a device using the relay.
If we apply current to the relay contact in any of the above cases no, nc, they will change their states i. This section will help to enable those with limited electronics experience to successfully complete these interfacing tasks. Microcontroller interfacing to relays using uln2003, in this article, you will learn how to interface microcontroller to relays using uln2003 relay driver circuit. But have run into a problem while interfacing the micro controller with a relay. A normal bipolar transistor used in switch mode like the bc108 or a darlington pair like the bcx38 can do the job. Relay interfacing with microcontroller using uln2003a. Write the command to the datacommand port of the lcd through our 8051 microcontroller.
Mar 02, 20 interfacing relay with pic microcontroller using transistor. Microcontroller do not have considerable amount of current to operate relay. The tutorial begins with instructions on selecting a specific pic and ends with directions for breadboarding the microcontroller. Through eight realworld projects, clear illustrations, and detailed schematics, making pic microcontroller instruments and controllers shows you, stepbystep, how to design and build versatile picbased devices. Interfacing a relay with microcontroller electronics forum. Automatic street light control using 8051 micro controller,keil ide and proteus simulation duration. A relay can be used to switch higher power devices such as motors, light bulbs and solenoids.
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