A multifunction digital meter using Atmega128

Posted on by 3 comments

This is a multifunction bench test instrument built using an Atmega128 microcontroller and incorporate a lot of functions like voltmeter, ammeter, logic analyzer, frequency generator, frequency counter and also provides regulated DC power supply. This device is interfaced with a Windows PC to display the measurements. The PC software is developed in VB 6. The function generator is based on a MAX038 IC that can provide sine, triangle or square wave, with adjustable duty cycle, from about 1 Hz to > 20 MHz.

Read more

AVR digital clock with white seven segment LED display

Posted on by One comment

This is a digital clock project based on an ATtiny26 microcontroller, displaying time on four seven segment LEDs. The seven segment LEDs glow bright white and are multiplexed through PORTB pins, whereas the segments are driven by PORTA pins. The time is normally shown in hh.mm format but it can be switched to display mm.ss too. The time setting can be done with two push button switches.

Read more

Low power temperature data logger using PIC18F27J53

Posted on by Leave a comment

Most of the microcontroller based data loggers use external EEPROM chips for storing the measurement values. This increases the cost, power consumptionm, and the size of the circuit board. Instead, why don’t we choose a microcontroller with a larger flash memory and use it for storing the data. Actually, a data logger’s firmware is not very big in size. So, the remaining flash memory can be used to store the data from realtime measurements. This project is based on the same concept and uses a PIC18F27J53 microcontroller that has 128K programmable flash memory. The PIC18F27J53 family microcontrollers are low power

Read more

Calibrating a thermistor for temperature measurements

Posted on by Leave a comment

A thermistor is a passive device that changes its resistance with temperature. If the temperature-resistance characteristic is known, it can be used as a temperature sensor by measuring the resistance, or more precisely, the voltage across it. Thermistors are classified in to two types: NTC (negative temperature coefficient) and PTC (positive temperature coefficient). A NTC thermistor decreases its resistance while the temperature rises, and a PTC does the opposite. Although the datasheet of a thermistor describes the temperature-resistance relationship, the measurement based on that is not very accurate. Therefore, you may need to calibrate it against a more accurate sensor.

Read more

Portable 2.4 GHz Spectrum Analyzer using Atmega8

Posted on by Leave a comment

There are plenty of wireless devices available on the market that broadcast in the 2.4 GHz ISM band. Such devices include Bluetooth, WiFi, Zigbee, wireless USB, cordless phones, wireless mice and keyboards, etc. This project describes a wireless spectrum analyzer to examine the surrounding radio frequencies in 2.4 GHz band. The project is based on the Cypress’s CYWUSB6935 radio module. It is a complete radio module with PCB trace antenna and it operates in the unlicensed Industrial, Scientific, and Medical (ISM) band (2.4 GHz- 2.483 GHz). The radio module is interfaced with an Atmega8 microcontroller, and the recieved spectrum is

Read more
« Older Entries Recent Entries »