Arduino Sine Wave Dimmer

For a smooth signal we choose phase correct pwm at a frequency 31372 hz see previous post.

Arduino sine wave dimmer.

The above chopped signal may not look like sine wave. To generate a sine wave we will use two pins one for positive half cycle and one for negative half cycle. But begin a simple design the chopping frequency stay constant and good enough to run most of electronic gadgets. A real sine wave inverter s chopped wave form increase and decrease exponentially across x axis.

Program developed by r girish. First zero to control the passing of phase null of ac which is used to initiate the interrupt signal. It is not for any inductive load as it is dc biased. Second dim psm to control dim current.

In our post for this we use pins 5 and 6 that means timer 0. To build a dimmer the zero crossing points the points where the wave changes its polarity are important. You just have to program the arduino board with the spwm code as explained in the. This one channel ac dimmer made using the arduino uno board using a specified coding.

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. The square wave can be observed using a cro which is connected to the pin number 8 and the sine wave can be. This circuit is only for incandescant bulbs. 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.

Dimmer is connected to arduino controllers via two digital pins. 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. Ac dimmer circuit made by using triac and optocoupler. 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.

The figure 2 demonstrates the schematic diagram of the whole circuit. 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. Opening the triac after a number of microseconds delay starting from the zero crossing therefore gives a predictable level of dimming.