November | 2010 | Embedded Lab

Monthly Archives: November 2010

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.

VGA display using PIC Micro

Posted on November 24, 2010 by R-B Leave a comment

VGA stands for Video Graphics Array, which is a widely used analog interface between a computer and monitor that uses a 15-pin plug and socket. The VGA display requires accurate timing signals and synchronization. The goal of this project is to generate VGA signals using a PIC microcontroller to display characters, text and figures on a computer monitor. It uses a PIC18F452 microcontroller running at 4 MHz external crystal to generate accurate timing signals to drive VGA pins. The software is written in assembly so that timing signals will be more accurate. The author also provides a brief introduction of

Turn your TV into a Digital Voltmeter

Posted on November 23, 2010 by R-B Leave a comment

This is an interesting voltmeter project that display the measured voltage on a TV screen, in giant digits as well as with analog bar. It also records the maximum and minimum values of measurements. The project was built by Alberto Ricci Bitti and was published in the May 1999 issue of Elektor Electonics.

A brief tutorial on frequency measurements

Posted on November 22, 2010 by R-B One comment

Measuring the frequency of a signal may seem to be a simple process of counting pulses, but in order to get better accuracy, few other things should be considered, such as the gating interval and the range of measurement. This tutorial, posted on the pcbheaven.com, briefly describes two typical methods of frequency measurement: Direct Frequency Measuring (DFM) and the Reverse Frequency Measuring (RFM), with their pros and cons. The shape of the incoming signal may be distorted and of varying amplitude. Therefore, some sort of signal conditioning along with a voltage limiter is required prior to the frequency counter circuit.

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