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Microcontroller tutorial series: AVR and Arduino timer interrupts

Microcontroller tutorial series: AVR and Arduino timer interrupts
Does your program seem like it’s trying to do too much at once? Are you using a lot of delay() or while() loops that are holding other things up? If so, your project is a good candidate to use timers. In this tutorial, we’ll discuss AVR and Arduino timers and how to use them to write better code. In our prior article, we covered interrupt basics and how to use external interrupts that are triggered by a pin change or similar event. Check it out if you’re looking to brush up on interrupts in general. This chapter moves on to timer interrupts and talks about their applications in Arduino projects or custom AVR circuits. What is a timer? You’re probably familiar with the general concept of a timer: something used to measure a given time interval. The beauty of timers is that just like external interrupts, they run asynchronously, or independently from your main program. For example, say you’re building a security robot. How do timers work? Our timer resolution is one millionth of a second.

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Arduino Frequency Counter Tutorial with Circuit Diagrams & Code Almost every electronic hobbyist must have faced a scenario where he or she must measure the frequency of signal generated by a clock or a counter or a timer. We can use oscilloscope to do the job, but not all of us can afford an oscilloscope. We can buy equipment for measuring the frequency but all these devices are costly and are not for everyone. With that in mind we are going to design a simple yet efficient Frequency Counter using Arduino Uno and Schmitt trigger gate. This Frequency Counter is cost effective and can be easily made, we are going to use ARDUINO UNO for the measuring the frequency of signal, UNO is the heart of project here. To test the Frequency Meter, we are going to make a dummy signal generator.

EXTERNAL INTERRUPTS ON THE ATmega168/328 - QEEWiki External Interrupt Mask Register External Interrupt Flag Register ATmega168/328 Code: #include <avr/io.h> #include <avr/interrupt.h> Studfinder: Wire Edition - CraigM Craig Macomber, Milda Zizyte June 10, 2011 Often, humans are faced with the problem of finding that which they cannot see. The five senses are limited and in particular do not extend to wavelengths outside the audible or visible spectrum. Tutorials In our previous Atmel tutorial, we talked about how to set up the powerful AVR Studio 5 IDE to incorporate Arduino libraries and projects. As flexible as AVR Studio 5 is, it had a few issues, and Atmel has been hard at work hustling the next major version out the door. Now, rebranded as Atmel Studio 6 (no longer just for AVRs!), the new version promises to be better, faster, and easier to use. Here, we’ll show you the quickest way to get up and running if you want to use Arduino code with all of the new features.

Dimmer-Arduino – Arduino&stuff Switching an AC load with an Arduino is rather simpel: either a mechanical Relay or a solid state relay with an optically isolated Triac.It becomes a bit more tricky if one wants to dim a mains AC lamp with an arduino: just limiting the current through a Triac is not really possible due to the large power the triac then will need to dissipate, resulting in much heat and it is also not efficient from an energy use point of view. The proper way to do it is through phase control: the Triac then is fully opened, but only during a part of the sinoid AC wave.One could an Arduino just let open the Triac for a number of microseconds, but that has the problem that it is unpredictable during what part of the sinuswave the triac opens and therefore the dimming level is unpredictable. One needs a reference point in the sinus wave.For that a zero crossing detector is necessary. Opening the Triac is done via a tried and tested opto coupled Triac circuit. All one needs then is the software.

HOW TO GET WHAT YOU WANT In many of our textile sensor videos and examples we use an arduino programmed to read analog sensor values and send them over serial to a computer running a visualization written in processing. We have taken our code from the following examples: “Arduino meets Processing” Potentiometer example >>

scheduler - avrtutorials2 My final year project will be an implementation of a Real Time Operating System (RTOS) for the AVR microcontrollers. Although many have said it isn't wise to write yet another OS (apparently, there are enough of these around), I decided it is the best way to learn, since the source of other OSes weren't as easy to understand as I had expected.To start off, I began with the Scheduler. What is a Scheduler? A scheduler is a piece of code that calls functions (usually refered to as "Tasks") at periodic intervals of time. Schedulers form one of the basic components of an RTOS.

Ready, Set, Oscillate! The Fastest Way to Change Arduino Pins « The Mind of Bill Porter There are many ways to change an output pin. The way we know and love is the famous digitalWrite() function. (Spoiler: Want a faster digitalWrite? Download Here!) Tutorial: Using AVR Studio 5 with Arduino projects Note: This tutorial has been replaced with an updated version that covers the same topic with Atmel Studio 6. Studio 6 makes a lot of improvements over the prior version, so there’s really no reason not to upgrade unless you have a very specific need. We’ve also incorporated a lot of fixes, tips, and great user feedback. Check it out here:

Zero-Crossing Detectors Circuits and Applications Fig. 1 by Lewis Loflin A zero-crossing detector is used to generate a sync pulse related to the AC voltage phase angle often used in power control circuits. Fig. 1 shows the relationship of a zero-crossing pulse to a sine wave.