But begin a simple design the chopping frequency stay constant and good enough to run most of electronic gadgets.
Arduino sine wave dimmer.
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.
You just have to program the arduino board with the spwm code as explained in the.
A real sine wave inverter s chopped wave form increase and decrease exponentially across x axis.
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.
Second dim psm to control dim current.
First zero to control the passing of phase null of ac which is used to initiate the interrupt signal.
Program developed by r girish.
To build a dimmer the zero crossing points the points where the wave changes its polarity are important.
For a smooth signal we choose phase correct pwm at a frequency 31372 hz see previous post.
To generate a sine wave we will use two pins one for positive half cycle and one for negative half cycle.
The figure 2 demonstrates the schematic diagram of the whole circuit.
A zero cross detector circuit is required for ac dimming purposes.
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.
Ac dimmer circuit made by using triac and optocoupler.
Dimmer is connected to arduino controllers via two digital pins.
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.
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.
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.
This circuit is only for incandescant bulbs.
To grab these points we have to use a zero crossing detector.
In our post for this we use pins 5 and 6 that means timer 0.
