Serial Communication with PIC16F877A

This article series aims at teaching serial communication between a PIC microcontroller and a PC. We first introduce you with what is serial communication is and how it can used. Then we tell you how to perform serial communication using PIC microcontroller and how we use the USART peripheral for the purpose. We will tell you how our usart library for PIC16F series can be used for easy serial communication, in this part we also discuss how to set up a MPLAB X project for using the USART library. After that we will build a demo project to explore the library. Finally we will burn this demo in a PIC16F877A and establish a serial communication with PC. Serial Communication Their are several serial communication standards like RS232, SPI, I2C etc. Of which RS232 is a asynchronous method. That means it does NOT have a synchronizing clock line. One way data requires only one conductor line. Since it is a two way communication their are two lines between the two device. One for sending data called the Tx and one for receiving data called the Rx. The communication is full duplex, that means data can be sent at the same time data is being received. generally other serial communication like SPI and I2C are used for short range communication like between […]


Making A Thermometer with PIC16F877A

At basic level on microcontroller you can create this interesting project of digital thermometer. It teaches you how to acquire analog data from a sensor and display it on a lcd. We will use a popular MCU PIC16F877A to implement this mini project. The temperature will be read using a LM35 precision sensor. Final result will be shown on a 16×2 alphanumeric lcd module. Fig. PIC16F877A Based Thermometer with LCD   Stuffs Required S. No. Item Image Cost 1 40 PIN PIC Development Board Rs. 769 2 16×2 LCD Board Rs. 296 3 Single PIN Burg Wires Female/Female 20 units Rs. 100 4 12V 1A DC Adapter Rs. 127 5 LM35 Rs. 60     Total Rs. 1,352 Connections The PIC16F877A development board has the PIC16F877A microcontroller chip and its supporting basic circuitry all in a nice high quality PCB. The development board comes fully assembled and tested, thus makes it ideal for doing experiments for learning by beginners. 40 PIN PIC Development Board In the bottom portion of the pic development board you can see a row of male headers. Most of these pins are the microcontrollers general purpose input/output lines and the rest are 5v and GND supply lines. Using these pins you can connect external peripherals (like the LCD board or something else) to do your experiment. […]

LCD Library for PIC – Setup on MPLAB X IDE

This article describes the setup and use of the C library for hd44780 based alphanumeric lcd modules. This library is also available for the AVR family of microcontrollers. This part is focused on its usage with PIC16F series of MCUs from Microchip. Here we describe how to setup a MPLAB X project with support for lcd related functions. The library is designed for compilation and use with Microchip’s XC8 C Compiler. Fig. LCD Demo   Creating a New Project in MPLAB X You can create a new project using the MPLAB’s Start page as shown below. Fig. MPLAB X Start Page Alternatively you can use File->New Project Fig. Select New Project from File Menu And for those who love the Keyboard over mouse can hit <Ctrl>+<Shift>+<N> Any of the three method will launch the New Project Wizard as shown below. The first step is the selection of project type. From the Categories list select Microchip Embedded and from Projects select Standalone Project. Fig. Project Type Selection Second step is the selection of device for which the project is targeted. Select Mid Range 8-bit MCUs (PIC12/16/MCP) in Family and PIC16F877A in Device. Fig. Device Selection Third step is the selection of debug tool. For that select Simulator. Fig. Tool Selection Microchip MPLAB lets you install more that one compiler. It also […]

LCD Module Interface with PIC16F877A

This article describe the hardware setup required for interfacing HD44780 based alphanumeric LCD modules with a PIC16F877A microcontroller. The software part consisting of the LCD library for PIC, its setup and use with MPLAB X IDE and XC8 compiler are described in a separate article. LCD Library for PIC – Setup on MPLAB X IDE A common controller chip used in many alphanumeric LCD module is the HD44780. The purpose of the controller is to generate pixel patterns and drive individual pixels of the LCD to show characters and symbols. In this method the main microcontroller running your application code does NOT need to generate the pixel patterns, it just need to tell the controller chip which character or symbol to show the rest is done by the controller, i.e. the HD44780. The same controller chip is used in many differently sized alphanumeric LCDs. Thus the connection schematic and driving code is same. Pin Details of LCD Module All HD44780 based LCD modules have 16 pin connecters. The detail about these pins is given below. Interface pins of LCD Module   Pin Number Pin Name Pin Type Connected with PIC16F877A’s pin 1 VSS Power Supply – 2 VCC Power Supply – 3 VEE Contrast Adjust – 4 RS Control Line RD4 5 R/W Control Line RD5 6 E Control Line […]


Getting Started with AVR Microcontrollers

The first step in getting started with microcontrollers is to choose a microcontroller family to work with. Their are hundreds different microcontroller families from many different manufactures. Selecting a Microcontroller There are two family of microcontroller that are extremely popular among hobbyist. The “PIC” series from Microchip and “AVR” series from Atmel. Both these chips are wonder of modern microelectronics. PIC had ruled for a long time but now AVR is also getting in serious competition. Speed and ease of use. I prefer AVRs because one major reason. They are fast. When a PIC and an AVR is running with same frequency lets say 16 MHz, then the AVR is actually executing four times faster than the PIC ! Yes 4 times faster. This is because the PIC requires 4 cycle to perform a single execute cycle while the AVR execute most of the instruction in 1 clock cycle. In addition, I like the AVR architecture because of its consistency. It makes using the most advanced feature of AVR very easy to use. These chips are easily available and they are cheap. Free “C” compiler. One more important thing, generally microcontroller programs are written in assembly language for efficiency. Which you may know is a very low level and unstructured language. Therefore, to achieve a small thing lots of code […]


Remote Temperature Monitoring using GSM – AVR Project

If you want a live demo of this, please register from the link given below. (Only in Pune) REGISTER NOW! This project can also be implemented using a PIC18F4520 microcontroller. Temperature monitoring have wide application in daily life. In modern day keeping an eye on temperature of places such as server rooms, hospital rooms, warehouses and green houses can help solve many problems. But with the use of normal temperature sensors, someone needs to go to the place in order to view the temperature. But with the development of GSM network, one can easily connect the sensor with GSM network, so that you don’t need to be present near the sensor in order to view the temperature. You can just pick up your cell phone and send a request to your sensor by a text message and in no time you will receive the temperature of the remote place ! The advantage is the you don’t need any kind of "special" device at the receiver end. You can use any cell phone to view the remote temperature. This reduces cost as you already have a cell phone. Other benefit is that the range is not limited. You can be at any place in the world (with mobile coverage of course!), to request temperature data from your room. Fig. SMS Based […]


Introduction to AVR Microcontrollers

Just what is a microcontroller? To get you understand quickly I define a microcontroller as a single chip computer. Yes it is a full blown computer in its own. It has a C.P.U., RAM, some amount of EEPROM (for secondary storage i.e. permanent storage without power), many on-chip peripherals(Timer,Serial communication, Analogue to Digital converters etc.). If you don’t understand, no problem I will be dealing them in detail in next tutorials. But compared to a P.C. their resources(RAM,speed etc)are less. But that is what is required ! Because P.C. is a general purpose computer, which means it can run thousands of different software that are available for specific needs. Like it can run a game. The same P.C. can run this browser in which you are reading this! It can run a custom solution for banks,railways and airways. It can run a 3D modeling, video editing & image editing software for a production company. Many of these are huge software,requiring lots of memory and CPU power. And a P.C. can run simultaneously many of these ! So to run them the host computer should have enough RAM and CPU power so that it can run heaviest of them. But in case of a microcontroller(aka MCU) which is used for a specific purpose like switching a Microwave oven heating off after […]

AVR UBRR Calculator for Android

If you have worked with AVR’s USART you must be knowing that the first step is to figure out the value of UBRR (USART Baud Rate Register) the formula is given in the datasheet. So every time you need a new baud rate or you change the clock speed of MCU, you need to recalculate the new UBRR! This includes finding the datasheet, opening it and then finding the page in which the formula is given! Then you need to search for your scientific calculator (well in my case I don’t like Windows calculator much !) and do the calculations only to find out that the error is too high! And the baud rate cannot be implemented! So you go over again and select new baud rate which is near to the required one, and repeat the calculation process. To save all this trouble I have made a small Android app to get all this job done with out the datasheet or the calculator ! And believe me finding a scientific calculator in your desk is way tougher than finding your cell phone Features Runs on Smart Phones/Tablets powered by Android 2.2 or higher. Supports calculations for Normal, Double Speed and Asynchronous modes of USART. Displays result in both HEX and Decimal Formats. Displays error rate in transmission/reception for selected […]


Interfacing Analog Joystick with AVR ATmega32

If you have played games on console you must be knowing what a joystick is. In games a joystick is generally used to control the motion of character or a vehicle (like plane or car). Joystick give a very realistic two dimensional control! Joystick are also used to control the motion of real objects like a robot or a car. Generally we want to control the back and forth motion of any object along with the ability to make it turn left and right. For this we use a common joystick with two axis. The y axis is used to move the object forward and backward, while the x axis is used to turn the object left or right. The type of joystick we are using in this article is an Analog Joystick that means it can give the magnitude of motion along with the direction. For example you can push the joystick little forward to make you robot start moving forward slowly. You can push the joystick further up to increase the speed of forward motion faster. Similarly you can control the speed of robot while making a reverse motion. Turning magnitude can also be controlled in the same way by moving the joystick left or right. Fig. 1 – An Analog Joystick   Working of Analog Joystick. Analog […]

Door Entry Detection for MCU Based Designs

This article discuss how you can detect the entry of a person in a room and get this signal inside your MCU. This is NOT a complete project but just an idea that can be implemented in many different projects. The technique is to use use an IR transmitter and a receiver pair. One side of door will have an IR Transmitter and the other side of door will have an IR Receiver. The transmitter (Tx in short) will continuously send IR beam to the receiver, as long as the receiver(Rx in short) will receive this beam it will give a voltage output in range of 2.5v to 3.0 volts. But as this beam is obstructed, for example by someone entering the room, the receivers output will tend towards 4.5 Fig. 1 – Schematic For Door Entry Detection The IR Transmitter can be made on a small PCB as shown below. It has four mounting holes to fix it in the wall near the door. Please use 1 Watt resistor for R2 and R3 (22ohms). Fig. 2 – IR Transmitter Module Similarly the IR receiver module is made. Fig. 3 – IR Receiver Module.   Mount the IR Transmitter and Receiver as shown in the image below. Fig. 4 – Mounting the Modules on Door. As you can see the […]


Interfacing TCS3200 Colour Sensor with AVR ATmega32

Detecting colour of an object can be an interesting and useful electronic application. It can be realized using a colour sensor like TCS3200 and a general purpose microcontroller like AVR ATmega32. TCS3200 Colour Light to Frequency Converter Chip Fig. TCS3200 Chip .   TCS3200 chip is designed to detect the colour of light incident on it. It has an array of photodiode (a matrix of 8×8, so a total 64 sensors). These photodiodes are covered with three type of filters. Sixteen sensor have RED filter over them thus can measure only the component of red in the incident light. Like wise other sixteen have GREEN filter and sixteen have BLUE filter. As you should know that any visible colour can be broken into three primary colours. So these three type of filtered sensors helps measure the weightage of each of primary colours in incident light. The rest 16 sensors have clear filter. TCS3200 converts the intensity of incident radiation into frequency. The output waveform is a 50% duty cycle square wave. You can use the timer of a MCU to measure period of pulse and thus get the frequency. The output of TCS3200 is available in single line. So you would ask how we get the intensity of RED,GREEN, BLUE and CLEAR channels? Well it has two inputs S2 and […]


SMS Based Voting System – AVR GSM Project

If you want a live demo of this, please register from the link given below. (Only in Pune) REGISTER NOW! This project can also be implemented using a PIC18F4520 microcontroller. Hi friends ! Here I am showing a microcontroller based project called the "GSM Based Voting System". Using this system you can ask your users to vote for any of the four options. Four available options are identified by a letters ‘A’, ‘B’, ‘C’ and ‘D’. User can vote for any option by sending a text message to the mobile number. For example if you want to create a poll like this. Which is your favorite phone brand? A: Nokia B: Apple C: Samsung D: L.G. So your user can vote for any of the four brands by sending a message like this VOTE x where x is the choice he/she wish to vote for. For example if they want to vote for Nokia, then they should send a message like this : VOTE A The number of vote received for each option is shown in real time on the LCD Module. The votes are stored in the internal EEPROM of the AVR so they are not lost on power failures. That means even if you switch off the device and switch it on after few days (or few years!) […]