Arduino Sine Wave Dimmer

This one channel ac dimmer made using the arduino uno board using a specified coding.

Arduino sine wave dimmer.

For a smooth signal we choose phase correct pwm at a frequency 31372 hz see previous post. It is not for any inductive load as it is dc biased. A zero cross detector circuit is required for ac dimming purposes. In the last article we learned how to generate sine wave pulse width modulation or spwm though arduino we are going to use the same arduino board to make the proposed simple pure sine wave inverter circuit the design is actually extremely straightforward as shown in the following figure.

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

Demodulated waveform of variable frequency sine wave using arduino on cro. The figure 1 shows the mains sinusoidal wave with the frequency of 50hz sometimes 60hz. To generate a sine wave we will use two pins one for positive half cycle and one for negative half cycle. Program developed by r girish.

Ac dimmer circuit made by using triac and optocoupler. But begin a simple design the chopping frequency stay constant and good enough to run most of electronic gadgets. To build a dimmer the zero crossing points the points where the wave changes its polarity are important. In our post for this we use pins 5 and 6 that means timer 0.

The above chopped signal may not look like sine wave. You just have to program the arduino board with the spwm code as explained in the. The square wave can be observed using a cro which is connected to the pin number 8 and the sine wave can be. 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.

A real sine wave inverter s chopped wave form increase and decrease exponentially across x axis. Dimmer is connected to arduino controllers via two digital pins. This circuit is only for incandescant bulbs. First zero to control the passing of phase null of ac which is used to initiate the interrupt signal.