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Arduino’s AnalogWrite – Converting PWM to a Voltage

Arduino’s AnalogWrite – Converting PWM to a Voltage
D-A_converter When I first started working with the Arduino platform (it was also my first experience with microcontrollers), I was a little surprised that analogWrite didn’t actually output a voltage, but a PWM (pulse-width modulated) signal. After all, the ATmega had a A-D (analog to digital) converter along with Arduino’s analogRead. The complementary analogWrite function was there, but no D-A (digital to analog) converter on the AVR chip itself. Fortunately, there is an easy way to convert a PWM signal to an analog voltage. PWM Primer Pulse width modulation (or PWM as it is most commonly known), is a way of encoding a voltage onto a fixed frequency carrier wave. With the need for digital communication, a new modulation technique was invented – PWM. PWM outputs (curtesy For the Arduino, you write a value from 0 to 255 on a PWM pin, and the Arduino library will cause the pin to output a PWM signal whose on time is in proportion to the value written. Modulating a Signal

So You Want to Build Electronics The equipment you need to get started in building electronics. If you look back through the last two years of posts on this blog, you'll see my relatively rapid transition from absolute beginner in electronics to someone who is formidable enough to have their work at least noticed (See HaD every other month). This means I've been fielding a lot of questions from beginners online as to how exactly to get started, and what to buy, and what to do with it. And to answer this, I keep having to pull up the same links to the basic stuff. The obvious beginner answers are the juggernaut kits from places like the Maker Shed, and I will never knock them for putting together a perfectly reasonable starter kit (which despite your intuition, is actually reasonably priced), but I've never been really interested in them. So here is a gigantic list of everything I would buy right now to replace my entire workshop if mine were to disappear.

ATmega168A Pulse Width Modulation – PWM - Protostack Dimming an incandescent bulb is easy. Simply adjust the current down using a potentiometer and you are done. Dimming an LED is another story entirely. With PWM the LED is turned on and off many times per second. LED dimming is not the only application of PWM. Source Code Example 1 The example below produces a PWM waveform with a 20% duty cycle. #include <avr/io.h>#include <util/delay.h> #define LED_PORT PORTC#define LED_PIN 0#define LED_off() LED_PORT&=~_BV(LED_PIN)#define LED_on() LED_PORT|=_BV(LED_PIN)int main (void){ DDRC = 0b10000000; while (1) { LED_on(); _delay_ms(2); LED_off(); _delay_ms(8); } return(0);} For most embedded applications, controlling PWM this way is not practical. PWM output lines on ATmega168A The ATmega168A microcontroller has 3 timers which in turn can control 6 PWM lines. On each timer, the ATmega168A has 4 modes that produce a PWM wave form. Each of the 6 PWM output lines can be set into 1 of 4 output modes. Fun with RGB LEDs Source Code Example 2 Downloads

L'électronique de zéro Bonjour à toutes et à tous ! Si vous êtes ici, même s'il s'agit d'un hasard, c'est qu'il y a une très grande probabilité que vous ayez envie de vous documenter ou d'apprendre l'électronique. Quels sont les principes de base ? Comment connaître les composants et pouvoir les utiliser pour faire des montages ? Comment faire ses propres montages ? Telles sont les questions auxquelles nous vous amèneront des réponses afin de satisfaire vos besoins sur le sujet. Nous commencerons le cours "en douceur" par les formules et les lois nécessaires et fondamentales à connaitre en électronique. Sachez toutefois que le domaine de l'électronique est tellement vaste que nous ne pouvons pas vous présenter toutes les facettes de cette science. Avis donc à tous les amateurs, les hobbyistes, les professionnels et les étudiants : vous venez de dénicher la perle rare !

10A H-Bridge Motor Controller - Introduction Motor control is the core heart of robotics. Without locomotion or any movement a robot is dull and lifeless. The H-bridge is a tried and true concept for DC motor control. It allows you to move motors forward, backward and with varying speeds through PWM (pulse with modulation). This tutorial will take a few steps back from the all-in-one L298 or LMD18245 motor control ICs and look more into how we can build our own H-bridge without the need of an IC. 10A H-Bridge Test Video 10A H-Bridge Completed 10A H-Bridge PCB And All Parts 10A H-Bridge With PWM Input Purpose & Overview of this project The main goal for this tutorial is to build a 10 AMP motor controller that can control a DC motor with a digital input.

Lab 14: Inter-Integrated Circuit (I2C) communication I2C (Inter-Integrated Circuit) is a short distance serial interface that requires only 2 bus lines for data transfer. It was invented by Philips in 1980′s, originally to provide easy on-board communications between a CPU and various peripheral chips in a TV set. Today, it is widely used in varieties of embedded systems to connect low speed peripherals (external EEPROMs, digital sensors, LCD drivers, etc) to the main controller. In this experiment, we will cover an overview of I2C protocol, its implementation in PIC microcontrollers, and the method of connecting single and multiple devices on a common I2C bus. I2C devices with PICMicro Theory I2C bus has two lines: a serial data line (SDA) and a serial clock line (SCL). Both SCL and SDA lines are open drain drivers, and are therefore, connected to a positive supply voltage through pull-up resistors. Start and Stop conditions Signaling for Start and Stop conditions I2C device addressing Data transfer Acknowledgment Serial EEPROM (24LC512) Output

Arduino and the AREF pin Learn how to measure smaller voltages with greater accuracy using your Arduino. This is chapter twenty-two of our huge Arduino tutorial series. Updated 12/12/2013 In this chapter we’ll look at how you can measure smaller voltages with greater accuracy using the analogue input pins on your Arduino or compatible board in conjunction with the AREF pin. Revision You may recall from the first few chapters in our tutorial series that we used the analogRead() function to measure the voltage of an electrical current from sensors and so on using one of the analogue input pins. And when we say the operating voltage – this is the voltage available to the Arduino after the power supply circuitry. This can easily be demonstrated by connecting an Arduino Uno to USB and putting a multimeter set to measure voltage across the 5V and GND pins. This is important as the accuracy of any analogRead() values will be affected by not having a true 5 V. Why does analogRead() return a value between 0 and 1023?

Tutorials The most fun you can have (after blinking LEDs) is using sensors to detect whats going on in the world and act on that information. However, all sensors have their own methods of interfacing. That can make them a real pain to work with: some need pull-up resistors, some need certain power supplies, some use lots of power, some don't. Since there aren't that many different sensors that people tend to want to use I have collected the most common sensors with code examples and wiring diagrams. Tutorials include: Force sensitive resistor - Used to detect physical pressure such as pinching, squeezing, pushing, brushing.

b e a . s t [an error occurred while processing this directive] Magnetic Levitation using Hall effect Sensor Feedback, and Matched resonant wireless power transfer This work was completed initially for a final project for Joe Paradiso's class MAS.836 - Sensor systems for Interactive Environments, taken Spring 2oo5. Click to watch the following movies:Magnet Levitation Movie [100 megs], or in Small form. Resonant Power Transfer movie [95 megs], or in Small form. Motivation: My goal is to build the subsystems to be able to magnetically [stably] levitate a lightbulb that is powered at all times through the air using a matched resonant air-core transformer. In order to levitate a lightbulb, there are three main systems that needed to be explored and techniques that needed to be developed. Implementation: The general goal setup is as shown to the right. Details of the system components are described below. In order to accomplish this, we build a resonant transformer [shown]. Hall Effect Sensing: Performance:

Motors and Microcontrollers 101 Electric motors are a key way of converting electrical power (voltage and current) into mechanical power (torque and speed), and because electric motors are simple and reliable machines, they can be found all over, in many different shapes and sizes. Just considering a normal (gasoline-powered) car, there are a great number of electric motors: the powerful starter motor and alternatoralternating windshield wiper motorsintermittent-use power windows and door locksthe blower fan that moves hot and cold air into the cabinthe tiny motors inside the CD player And I'm sure you can think of others. But from an electronics perspective, motors are slightly tricky loads to control -- they're not just a resistor! While a full analysis would have to look simultaneously at the motor and the attached mechanical system, in this video tutorial we're just going to address the electrical side of the system. Here are some photos and drawings related to the video (click to enlarge): Go give them a try!

Réalisations - Alim. led Electronique > Réalisations > Alimentations > Alimentation d'une LED Dernière mise à jour : 06/03/2016 Présentation Les lignes qui suivent décrivent comment utiliser une LED de façon isolée ou en groupe, avec des tensions alternatives ou continues. Bases - Alimentation en basse tension continue Une LED, si on l'alimente directement et sans autre forme de procès à une source de tension continue (pile 9 V neuve par exemple) ou à une source de tension alternative (secondaire d'un transformateur 220V / 9V par exemple), a 99% de chances de griller. Sur le schéma qui précède, la valeur de la résistance R1 est donnée à titre indicatif, la tension V n'étant pas spécifiée. La LED utilisée pour les deux expériences qui suivent est une LED verte fonctionnant de façon nominale avec une tension de 2,2 V et un courant de 20 mA. Bon, le courant traversant la LED (Iled) n'est pas de 20 mA tout rond, mais de 20,4 mA. Valeurs typiques de tensions et courants pour quelques LED Un point à ne pas négliger !

ABCelectronique, portail de l'électronique Hobby projects - Simple electronic circuits Computer microphones Learn how to interface electret and dynamic microphones to the standard computer sound card. Metal detectors Theory of operation and schematics of the most common metal detectors used today: Very Low Frequency (VLF), Pulse Induction (PI) and Beat-Frequency Oscillator (BFO). Wireless microphone The wireless microphone transmitter can be built in an afternoon with simple, affordable and widely available parts.