AVR is a family of microcontrollers developed by Atmel beginning in 1996. These are modified Harvard architecture 8-bit RISC single-chip microcontrollers. ATmega series are one of the types of AVR microcontrollers with features like 4–256 KB program memory, 28–100-pin package, extended instruction set, and extensive peripheral set. These special features help students, hobbyists and engineers make innovative AVR projects. Let’s take a look at few interesting AVR projects.
AVR Projects: Digital Soil Moisture Meter
A soil moisture meter is used for indicating the water content of a given soil sample. As crop production requires water at different stages and in different amounts, it is important to measure soil moisture from time to time. This project monitors soil moisture content in irrigation farms by measuring the resistance to the flow of electric current between two metallic probes. These probes act as sensor elements that register moisture and change it into an electric value. This value is further processed into information by an electronic display.
Details about the project are available at: digital soil moisture meter.
A radar system consists of a transmitter, transmitting a beam towards a target, which is reflected by the target as an echo signal. The receiver receives and processes the reflected signal to provide such information like the presence of a target, distance, position (moving or stationary) or speed, which is displayed on a display unit. Radar systems have a number of defense as well as civil applications. Air traffic control uses radars to track aircraft on the ground, in the air and to guide planes for smooth landings.
More details about this project are available at: ultrasonic radar model.
RFID Based Attendance System
This system can be used to take attendance for a student in school, college, and university. It also can be used to take attendance for workers in working places. Its ability to uniquely identify each person based on their RFID tag type of ID card make the process of taking attendance easier, faster and secure as compared to conventional method. The system can be connected to the computer through RS232 or Universal Serial Bus (USB) port and store the attendance in a database. An alternative way of viewing the recorded attendance is by using HyperTerminal software. A prototype of the system has been successfully fabricated. Radio frequency technology is used in many applications.
More details about this project is available at: RFID based attendance system.
Fingerprint Door Unlock System
This simple fingerprint sensor project using Arduino is very useful in door security, forensics, crime investigation, personal identification, attendance system and much more. In the future, there could be many more applications like fingerprint based driving license, bank accounts operation and so on. The whole system works on a simple matching algorithm. It compares previously-stored templates of fingerprints against users’ fingerprints for authentication purposes. In this project, only when an authorised person places a finger on the sensor, the door unlocks and the LCD displays a welcome message along with that person’s name.
More details about this project are available at: fingerprint door unlock system.
Sonar Water-Level Meter
A water-level indicator has two units: transmitter unit and receiver unit. The transmitter unit in the project is built around ATmega328P microcontroller (MCU) (IC1) with Arduino Uno bootloader, sonar sensor HC-SR04 connected at CON1, 433MHz transmitter (TX1), voltage regulator 7805 (IC2) and a few other components. A long spiral antenna is used for enhancement of its range. The contactless sonar sensor is placed at a strategic location on the tank so that it always gets the reflected signal from the water surface. The best place would be at the centre of a circular tank’s lid on top, or at the intersection of the diagonals of a rectangular tank’s top. The calculated tank level is transmitted with a coded authorisation to the receiver unit.
More details about this project are available at: sonar water-level meter.