Microcontroller based light dimmer using mikro c codes

please help me, I have to Dim an AC lamp using Micro-controller, but insteady of dimming, it is blinking, my circuit connection involves PIC,zero crossing detector and lamp connection. and am using mikro c codes below. where is the problem
can you help me please.....

unsigned Duty=0;
void InitMain()
{
TRISC=0x00;
PORTC=0x00;
PWM1_Init(5000);
}
void main()
{
InitMain();
//PWM1_Start();
while(1)
{
if (Duty==0)
{
PWM1_Start();
for (Duty=0;Duty<=255;Duty++)
{
PWM1_Set_Duty(Duty);
//Delay_ms (50);
}
}
Duty=255;
if (Duty==255)
{
PWM1_Start();
for (Duty=255;Duty>=0;Duty--)
{
PWM1_Set_Duty(Duty);
//Delay_ms (50);
}
}

you have set here a PWM coding.... u need additional circuit to do this.....

try this forum

Control the dimming of lights using microcontroller

what addition circuit do I need,

Can you post a schematic of your circuit and the entire code listing?

[IMG]C:\Users\user\Danyel\Xul\Project\Proj.Rep\report\c kt coloured.pdf[/IMG]
and codes are as shown above in my first comment.

Where's

PWM1_Start();
PWM1_Set_Duty();
PWM1_Init();

And this is going to help me much, an image file sitting on your computer:

[IMG]C:\Users\user\Danyel\Xul\Project\Proj.Rep\report\c kt coloured.pdf[/IMG]

and the code is as follows
unsigned Duty=0;
void InitMain()
{
TRISC=0x00;
PORTC=0x00;
PWM1_Init(5000);
}
void main()
{
InitMain();
//PWM1_Start();
while(1)
{
if (Duty==0)
{
PWM1_Start();
for (Duty=0;Duty<=255;Duty++)
{
PWM1_Set_Duty(Duty);
//Delay_ms (50);
}
}
Duty=255;
if (Duty==255)
{
PWM1_Start();
for (Duty=255;Duty>=0;Duty--)
{
PWM1_Set_Duty(Duty);
//Delay_ms (50);
}
}

Originally Posted by danyel

what addition circuit do I need,

Its already in that forum link... You have to refer it...

is there any mikro c codes instead of adding more circuits

hey guys, Do Triac accept Pulses From PIC directly???
if not how can I solve it in order for the triac to accept it

Here's a Microchip appnote discussing the use of a TRIAC with PIC interface:

Dimming AC Incandescent Lamps Using A PIC10F200/TRIAC

Appnote in PDF Form and Source Code.

thanks so much,
please,can you help mikro c codes. i want to use different duty cycles and it is controlled by one push button.

sorry,i have tested it but push buttons are not working to change duty cycle ,
I have put button into port A

I've tested the code on an EasyPIC 5 board and it performed as expected. Please post or upload your code?

Did you test the code in simulation or actual hardware? If hardware, what model PIC are you using?

Did you disable the ADCs or Comparators that are usually active by default on PORTA?

If not this is most likely the problem.

Hi,
I don't get what you're doing here. Why are you using PWM? You have to use phase angle control or pulse skipping. If you use phase angle control, you can't use the opto-triac that you used, you have to use a regular opto-triac such as MOC3021.

Why are you using 5kHz? You have to fire the triac with respect to the line frequency (50 Hz or 60 Hz). You have to sense the zero-crossing, and then decide how much time to wait before firing the triac and you repeat this the next cycle.

Assuming you're using an MOC3021 or something similar, when you set PWM duty cycle (the traditional DC-DC controlling PWM) at 20%, the output is high for the first 2ms and low for 8ms. But as soon as the output goes high, the MOC3021 fires the triac, which gets latched (on) until the next zero crossing.
Take any duty cycle and you'll see that the lamp will always light upto full brightness.

What you have to do is, if you need 20% brightness:
Half period is 10ms. So, your output needs to be on for 20% first half, then 20% second half. So, that means 80% off, this 80% is "cut" through phase control. Wait for 80% of the half-time, ie, 8ms and THEN send a high pulse to the MOC for about 100us and then turn the pulse low. Repeat this for the second half as well, and THEN you will get 20% brightness.

Take a look at this:
Phase fired controllers - Wikipedia, the free encyclopedia


Hope this helps.
Tahmid.

---------- Post added at 17:00 ---------- Previous post was at 16:57 ----------

Plus, you really need to use a resistor between the LED and mains. Add a 100k resistor. Add a resistor between the opto-triac output and the triac gate.

Originally Posted by Tahmid

Hi,
I don't get what you're doing here. Why are you using PWM? You have to use phase angle control or pulse skipping. If you use phase angle control, you can't use the opto-triac that you used, you have to use a regular opto-triac such as MOC3021.

Why are you using 5kHz? You have to fire the triac with respect to the line frequency (50 Hz or 60 Hz). You have to sense the zero-crossing, and then decide how much time to wait before firing the triac and you repeat this the next cycle.

Assuming you're using an MOC3021 or something similar, when you set PWM duty cycle (the traditional DC-DC controlling PWM) at 20%, the output is high for the first 2ms and low for 8ms. But as soon as the output goes high, the MOC3021 fires the triac, which gets latched (on) until the next zero crossing.
Take any duty cycle and you'll see that the lamp will always light upto full brightness.

What you have to do is, if you need 20% brightness:
Half period is 10ms. So, your output needs to be on for 20% first half, then 20% second half. So, that means 80% off, this 80% is "cut" through phase control. Wait for 80% of the half-time, ie, 8ms and THEN send a high pulse to the MOC for about 100us and then turn the pulse low. Repeat this for the second half as well, and THEN you will get 20% brightness.

Take a look at this:
Phase fired controllers - Wikipedia, the free encyclopedia


Hope this helps.
Tahmid.

---------- Post added at 17:00 ---------- Previous post was at 16:57 ----------

Plus, you really need to use a resistor between the LED and mains. Add a 100k resistor. Add a resistor between the opto-triac output and the triac gate.

thank you for your support
so do I need to change codes for this to happen(if yes which code do I have to change) or I have to change hardware parts,

Yes, you need to change your code. Have a look here:

mikroElektronika &bull; View topic - Triac Control
mikroElektronika &bull; View topic - Touchdimmer

In hardware, you have to add a zero cross detector. Check here:
Zero Cross Detector circuit and program using AVR?

Another approach is pulse skipping modulation (PSM), but you would still need to make the same changes to the hardware and make changes to the software as well.

Hope this helps.
Tahmid.