Arduino Sine Wave Dimmer

Ac dimmer circuit made by using triac and optocoupler.

Arduino sine wave dimmer.

The figure 1 shows the mains sinusoidal wave with the frequency of 50hz sometimes 60hz. A zero cross detector circuit is required for ac dimming purposes. This is a circuit that tells the arduino or another micro controller when the sinus wave goes through zero and therefore gives a defined point on that sinus wave. Program developed by r girish.

It is not for any inductive load as it is dc biased. Dimmer is connected to arduino controllers via two digital pins. The square wave can be observed using a cro which is connected to the pin number 8 and the sine wave can be. Opening the triac after a number of microseconds delay starting from the zero crossing therefore gives a predictable level of dimming.

In our post for this we use pins 5 and 6 that means timer 0. The pwm signal of an arduino is faster than the 50hz frequency so you will basically see the pwm signal modulated on the 50hz rectified sine wave making the effective voltage lower. To generate a sine wave we will use two pins one for positive half cycle and one for negative half cycle. For a smooth signal we choose phase correct pwm at a frequency 31372 hz see previous post.

First zero to control the passing of phase null of ac which is used to initiate the interrupt signal. The above chopped signal may not look like sine wave. This one channel ac dimmer made using the arduino uno board using a specified coding. To build a dimmer the zero crossing points the points where the wave changes its polarity are important.

A real sine wave inverter s chopped wave form increase and decrease exponentially across x axis. Second dim psm to control dim current. To grab these points we have to use a zero crossing detector. When the coding is finished one can verify and upload the code to the arduino board as explained in the project how to get started with the arduino.

This provides a stable signal at every zero level of the waveform and sends a signal to arduino to know about each zero level of a sine waveform. You just have to program the arduino board with the spwm code as explained in the. Demodulated waveform of variable frequency sine wave using arduino on cro. This circuit is only for incandescant bulbs.