Set frequency for white LED strip

Using Arduino LEDs and Multiplexing
1

Hi all,

I am new to arduino and I am looking for some help setting frequency of a strip of white LEDs. The LEDs are for lighting a demonstration. I am looking to set the frequency of the LEDs to a frequency of either 40 or 80 Hz. I currently have a simple code, posted below, that does not have any effect on the LED strip. Is there any hardware I need for this to happen, or do I need new code? I currently using an IRFZ44N transistor and am not sure if I am using it right or if I need it at all.

void setup() {
// initialize the digital pin as an output.
// Pin 13 has an LED connected on most Arduino boards:
pinMode(12, OUTPUT);
}

void loop() {
digitalWrite(12, HIGH); // set the LED on
delay(100); // wait for a second
digitalWrite(12, LOW); // set the LED off
delay(100); // wait for a second
}

2
3

delay(100);              // wait for a secondOne of those statements is incorrect.

4

That transistor isnt the right choice
Use a 'logic level' one..

5

I am looking for some help setting frequency of a strip of white LEDs.

Why? What advantage is there in flashing a strip faster than the eye can see? The result is only a half brightness strip, is that what you want?

6

I understand that 80 Hz is faster than what the eye can see, I am vibrating a silicone oil bath at 80 Hz and I wanted to make the viewing better. Vibrating the bath can cause droplets to bounce on the surface at this frequency. When I use 40 Hz it makes the droplets bounce appear better to the eye.

7

So basically you are making a stroboscope.

I agree with knut_ny, you need a logic level MOSFET such as irl540 or stp16nf06l. Otherwise you may not get full brightness and overheating of the MOSFET could occur.

Also, I'm not sure that a white led strip is the best choice. White LEDs contain phosphors which glow white in response to a UV led embedded inside them. The speed at which the phosphors respond to the led switching on and off may be slow and ruin the effect. With a stroboscope, you want the light flashes to be as short and intense as possible. An RGB strip, producing "white" light, may be a better solution. The red, green and blue LEDs in the strip contain no phosphors, so are able to switch on and off instantly.