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Running message display project for Christmas

Posted on December 8, 2010 by R-B 28 comments

Introduction

As Christmas is coming people have already lightened their houses. I thought of doing something different for this Christmas besides the festive Christmas lights. I made a running message display using LEDs, and thought of sharing it with you. This is a very simple running message display project that displays the message ‘MERRY XMAS’, where each letter is created with 5mm diameter red-color LEDs. The 9 letters in the message are individually turned on or off through a PIC16F688 microcontroller’s I/O pins. Therefore, a variety of display patterns can be generated through the software inside the microcontroller.

Christmas running message display

Monochrome Composite Video using Atmega8

Posted on December 6, 2010 by R-B One comment

This article describes the design of a Text on TV project. It takes serial data and displays text on a TV screen. The hardware part of this project is pretty simple. It uses an Atmega8 microcontroller that runs with a 16 MHz crystal. The article provides the details on PAL and NTSC timing signals, as well as how to implement the signals in software.

Breadboard module for PIC16F628A

Posted on December 3, 2010 by R-B 18 comments

Here’s another breadboard module that carries a PIC16F628A microcontroller. The power supply pins and the I/O ports of the PIC16F628A microcontroller are accessed through male headers. It can be easily plugged into a breadboard and is very useful for quick prototyping. It frees up a lot of space on the breadboard since the oscillator, reset, and ICSP circuits are already built on the module. It is different from the previous PIC16F688 breadboard module in the way that the microcontroller now runs with an external 4.0 MHz crystal. So, this module will be more appropriate for experiments that require accurate timing calculations. Besides, the PIC16F628a microcontroller allows you to read/write 8-bit data directly through PORTB, which is 8-bit wide (none of the ports in PIC16F688 were 8-bit wide).

The layout and the circuit diagram of the module is shown below. The module has ICSP header pins for in-circuit programming, a reset switch, and an LED as power-on indicator. It provides easy access to all the pins of PORTB, and RA0 through RA4 pins of PORTA. Pins RA6 and RA7 are used for external crystal connections, whereas RA5 is input only pin and is used for reset circuit.

Component layout

Playing “Happy Birthday” tune with a PIC Microcontroller

Posted on November 29, 2010 by R-B Leave a comment

This article describes how to play a melody with microcontrollers. A melody consists of notes that must be played with proper timing gap. Every note has a specific frequency. So if you know the notes that you want to play, then first find out the frequencies of those notes. After that, you can program a microcontroller to generate those frequencies at one of its port with proper timing intervals. You can listen the melody on a piezo buzzer connected to the port pin. This project describes the notes and frequencies to play the popular birthday tune.

Multi-channel temperature logger

Posted on November 25, 2010 by R-B Leave a comment

This project describes how to use all the 8 ADC channels of an Atmega48 microcontroller to read temperature sensors and the measured data to a PC for logging by using the built-in USART capabilities of the chip.

For demonstration, the temperature sensor used is LM335 that gives an output voltage proportional to the Kelvin temperature. The microcontroller is operated with a 9.21 MHz clock that works well for serial communication at 19200 baud. The software running on the PC is written in Python that keeps looking at the serial port and receives the incoming data.
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