Sensing Temperature Using AVR


In this new tutorial, we will be interfacing an LM35 based temperature sensor with ATMEGA32. The three main types are thermometers, resistance temperature detectors, and thermocouples. All three of these sensors measure a physical property (i.e., the volume of a liquid, current through a wire), which changes as a function of temperature. In addition to the three main types of temperature sensors, there are numerous other temperature sensors available for use. However, the LM35 based sensors are precision-integrated temperature sensors, with an output voltage linearly proportional to the Centigrade temperature. The main advantage is these types of sensors don’t require any external calibration. They are internally calibrated and simply generate the output to the temperature they detect. The device is used with single power supplies, or with plus and minus… Continue reading

Interfacing Ultrasonic Rangefinder with AVR

HC-SR04 sensor

In this tutorial, we are going to interface ultrasonic rangefinder with the all popular ATMEGA8. An ultrasonic rangefinder is used to find the range of an obstacle or a wall from the sensor. However, when there are cheap methods available to find a distance like the IR sensor or even a combination of LED’s and LDR would do, but the question is why we use a more expensive sensor. The reason is:- IR sensors are not accurate The result varies from object to object Calibration is required Works well only for short range Typically the IR sensors have a detection range from 30-80 cm or even less depending upon the manufacturer and also the LED’s used. However, for an ultrasonic rangefinder, the distance can be measured accurately up to 400cm… Continue reading

Interfacing analog Joystick with AVR

In this tutorial, we are going to learn something interesting which is already sued by many people to play games. Yes, the analog joystick which is used to control the motion of a vehicle or a character. They are also used to control the movement of an RC car or maybe an RC helicopter. Usually, all the joysticks are two axis joysticks. The ‘y’ axis is used to move the object forward or backward while the ‘x’ axis is generally used to move the object left or right. These joysticks are available both in digital and analog outputs. The digital joystick gives pulse width modulated output but is more costly than the analog output joystick. In this tutorial, we will get the input from the joystick from both the ‘x’… Continue reading

Interfacing shift register with AVR

74HC595 shift register

The shift register is one of the vital things to learn while designing an embedded system. Using shift registers, one can increase the number of input as well as output pins available in any microcontroller. There are situations, where you want to interface many peripherals together and also keep the low system cost as well as reliable. This is where the shift register come into the picture. For example, in a joystick used to play games, instead of running all the pins from the console to the joystick buttons, using a shift register reduces the number of pins almost by half.  This not only increases the reliability of the joystick but also has helped in saving a lot of money in the long run. Another advantage of using shift register… Continue reading

Controlling servo motor with AVR

Servo motor

Servo motors are a type of electromechanical actuators that do not rotate continuously like DC/AC motors. They used to position and hold some object. They are used where continuous rotation is not required, so they are not used to drive wheels. In contrast, they are used where something is needed to move to a particular position and then stopped and held there. The most common use is to position the rudder of aircraft and boats etc. Servos can be used effectively here because the rudders do not need to move full 360 degrees nor they require continuous rotation like a wheel. Servos are DC motors with built in gearing and feedback control loop circuitry. Most servo motors can rotate about 90 to 180 degrees. Some rotate through a full 360 degrees or… Continue reading

Interfacing character LCD to AVR

HD44780 character LCD

In this tutorial, we will be interfacing an HD44780 character LCD. Although as an alternative you can use JHD162A LCD. Both follow the same instruction set along with the same pin diagram. Both these LCD’s are readily available in the market at a low cost. HD44780 LCD has a set of 16 columns and two rows for display. The pin diagram of the LCD is as follows Continue reading