Ted salazar, applications engineering manager sep 29, 2003 abstract. Microcontroller interfacing techniques document revision. 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. Relay module interfacing with pic16f877a microcontroller. See the block diagram of driver circuit which i used in my project. Microcontroller may stop working by the negative voltages produced in the relay due to its back emf. Interfacing relay with pic microcontroller mikroc electrosome. For detailed working of relay please visit this page. Three very popular devices used to make things move include dc motors, rc servos, and stepper motors. Gsm interfacing with pic microcontroller pic16f877a make. 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. In order to control devices, it is necessary to interface or connect them to the pic microcontroller.
Microcontroller boardscontrol the relay operations by using pic16f18f slicker board. Relay provides isolation between two voltage levels and it is generally use to control ac appliances. How to interface rs232 with a microcontroller quora. The input is taken from the microcontroller pins and the output corresponding to each input is given to the 5 relays on the output. This lab session will look at how you can interface a dc motor to a pic microcontroller. A relay is a switch which is used to switch high voltage or current using low power circuits. The connection diagram for interfacing gsm module with pic microcontroller is shown below. A relay can be used to switch high power devices from a. Electromechanical relays interfacing circuits with.
If you want to use more relays, using transistors will be difficult. From mechanical to solid state relays, there are various type of relays are. As we did previously in bluetooth interfacing with pic microcontroller tutorial. A very small current flowing from base to emitter causes a large current to flow from collector to emitter. A relays is an electrical switch that opens and closes under control of another electrical circuit.
Wireless radio frequency rf communication between two microcontroller step by step. From mechanical to solid state relays, there are various type of relays are available in. As it can be seen from the above circuit diagram, a uln2003 is connected between the microcontroller and relays in order to drive multiple relays. We can drive two dc motors with one l293d, in this example we are using only the first pair of drivers to drive one dc motor. Relay is a mechanical device to control high voltage, high current appliances on or off from lower voltage levels. Interfacing pic microcontrollers, 2nd edition is a great introductory text for those starting out in this field and as a source reference for more experienced engineers. Ds5, spi, pic, real time clock, rtc, spi interface, pic microcontroller application note 2361 interfacing an spiinterface rtc with a pic microcontroller aug 25, 2003 abstract. Interfacing dc motor with pic microcontroller mikroc. Using the microchip pic18 family as a reference, it explains the architecture of the computer and the pic18 microcontroller, discusses how to program in both assembly and in clanguage, and then provides a solid discussion of interfacing, complete with. For interfacing relays, a npn transistor is generally preferred. Vdd and vss of the pic microcontroller is not shown in the circuit diagram. These are monolithic ic s consists of high voltage high current darlington transistor arrays.
Relay interfacing with pic16f877a friendly free download as pdf file. Interfacing circuits with microcontrollers, in this article i have discussed various elements and circuits interfacing with microcontrollers. Microcontroller basics pdf slides 46p this book covers the following topics. Before interfacing, every one should know about the relay driver which is used to interface the relay to microcontroller. Peripherals interfacing to the microcontroller 8051 in. These ad converter modules are primarily successive approximation register sar type and range in functionality from 8 to 12bit with channel size ranges of 4 to 16. Peripheral interface controller pic is new to elec. The image below show the schematic symbol for a npn transistor. So we connect output from our microcontroller pin to the base of transistor. In this project we will interface a relay with pic microcontroller pic16f877a. Applications of interfacing devices with microcontroller. A relay is an electromagnetic switch which is used to switch high voltagecurrent using low power circuits. It is activated by energizing a coil wounded on a soft iron core. Internally relay consist of a coil of wire wrapped soft iron core.
As you can see an npn transistor bc547 is being used to control the relay. Learn how control high power devices from a microcontroller using a relay in mikroc. Relay interfacing with pic microcontroller pic16f877a. In the multiprocessor system, processors can send interrupts to each other as communication between them, for example for the. This book provides a comprehensive look into the architecture, programming, and interfacing of the microcontroller. Interfacing relay with pic microcontroller using transistor. External hardware devices are sending interrupts to microcontroller in order to receive the treatment. Additionally, each device has a unique, factorypreprogrammed mac address and. Ive got pic16f877a on my development board and microchip ethernet interface enc28j60. Interfacing a relay to a pic microcontroller 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. Then i iniatized uart in pic send and received data to pc through hyperterminal its working properly. Rf modules are popularly used in remote control system. Manufacturer of the pic microcontroller range and mplab ide. A pic microcontroller is a single integrated circuit small enough to fit in the palm of a hand.
Programming with pic microcontroller research design lab. The picmicro mcu offers many options for smart solutions. To interface relay with microcontroller we need a driver circuit to drive the power to relay. Embedded design by interactive simulation 1st edition this edition is a comprehensive guide to interfacing microcontrollers based on the io devices of the pic 16f877 chip, including keypads, displays, analogue, timers and a full range of serial peripherals. You cannot directly interface an rs232 cable with a microcontroller. So, can use those two components together for some simple. Interfacing relay with pic microcontroller youtube.
Pdf this paper describes the implementation of a pic microcontroller in a. Interfacing is one of the important concepts in microcontroller 8051 because the microcontroller is a cpu that can perform some operation on a data and gives the output. To facilitate multiple features with simple circuits, microcontroller is interfaced with devices such as adc, keypad, lcd. The embedded ethernet solutions are offered with 10 baset and 100 baset phys. This section will help to enable those with limited electronics experience to successfully complete these interfacing tasks.
Optocoupler interface with pic microcontroller its very easy, connect any port pin you desire to pin number 1 of 817c through a resistor, and pin number 2 to ground. Now lets take a look on rf transmitter and receiver respectively. Interfacing the max1169 adc to a pic microcontroller. Here i used diode d11n4148ws, resistor r1 1k, transistor t1 bc547, 12 v power supply and 6v relay. How to interface relay with pic16f877a pic development board.
I am doing a project in which i will be interfacing a gsm modem with pic microcontroller16f877 when i connect the gsm modem with pc i can able to send and read the messages in the sim using at commands in hyperterminal. Interfacing converter to the picmicro microcontroller. A 32bit arm7 microcontroller is used in interfacing and software examples. It should not be directly connected to a pic microcontroller. Different dc motors need different voltages and operating high voltage motor from a low voltage controller is not a feasible option. Relay interfacing with pic16f877a friendly pic microcontroller. Limit the current in input led of optocoupler to 10ma by the resistance and output of it is an npn transistor, connect it as you require. We have simply interfaced the tx and rx pins of the gsm module with the rx and tx pins of the pic mcu pic16f877a respectively. I am beginner in the microcontroller world, i started to work with pic mcus and writing simple programs in assembly.
Automatic street light control using 8051 micro controller,keil ide and proteus simulation duration. This will establish a serial connection between both. Interfacing a relay with pic microcontroller mikroc. Pdf design and implementation of electronic control trainer with. Led blinking using pic controller 16f877a with mplab. Interfacing is a technique that has been developed and being used to solve many composite problems in circuit designing with appropriate features, reliability, availability, cost, power consumption, size, weight, and so on. Relay module interfacing with pic16f877a microcontroller, in this pic microcontroller tutorial you will learn how to interface relay module with any pic microcontroller or any microcontroller. Interfacing of relay with microcontroller aticleworld. Relay isolates low power circuits from high power circuits. Perhaps one of the most entertaining things to do with an embedded microcontroller is to get it to actually move something. Relay module interfacing with pic16f877a microcontroller ac load. I am interested in simple controlling via lan such as switching led onoff.
This application note provides an example schematic and software for using the ds5 realtime clock rtc with a pic microcontroller. 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. Microcontroller components, a typical microcontroller application, motorola 68hc12 microcontroller, 68hc12 programming model, 68hc12 data types, auto prepost decrementincrement, indexed addressing, 68hc12 move instructions, hc12 logic instructions, multiply and accumulate. See the block diagram below to how we turn on or off a 230 volt ac bulb by micro controller. How to turn on and turn off relay with pic microcontroller by using digital output ports of pic16f877a microcontroller. Part 1 introduces the pic 16f877 architecture, software, and simulation system. Martin bates has drawn upon 20 years of experience of teaching microprocessor systems to produce a book containing an excellent balance of theory and practice with numerous working examples throughout. Dc motors need much more current than a microcontroller can provide, so it needs separate drivers. 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. So by using relay switch we easily turn on or off any high voltage device by microcontroller. The transistor is driven into saturation turned on when a logic 1 is written on the port pin thus turning on the relay. However to perform the operation we need an input device to enter the data and in turn output device displays the results of the operation. Interfacing relay with pic microcontroller using uln2003.
Pic microcontrollers can be used as the brain to control a large variety of products. The maximum current that a pic microcontroller can source or sink is 25ma while a relay needs about 50 100ma current. Relay interfacing with microcontroller 8051 microcontroller. Embedded design by interactive simulation discusses microcontroller design and applications. Interfacing dc motor with pic microcontroller using l293d. The micro can send to itself an interrupt as a result of executing the code to report the failure in the process. Sign up to get notified when this product is back in stock.
Write a program to blink the led 1 if sw5 is on and blink the led2 if sw6 is on. Following things should be taken into account while designing the. You need a max232 in between so that it can scale down the voltage values to a range of 05v because microcontrollers cant handle more than that. Microcontroller interfacing circuits pdf 44p download book. You can connect seven relays using uln2003 and eight relays using uln2803. In this project we will interface a relay with pic microcontroller pic16f877a and control a 220v ac lamp using the relay.
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