Trying to control 12 leds so they randomly fade in and out in a twinkle effect. I have LED's on digital pins 2-12. I found another post that has them turning on and off, but not fading.. I'd also love to be able to adjust the maximum intensity, but so far I just know enough to be dangerous.
Here was the other page I was looking at, with the programming from Grumpy_Mike so far being the closest for what I am looking to do.
Welcome to the forum
In order to fade an LED it needs to be powered by a PWM signal. From the pin numbers that you quote is sounds like you are using a board such as a Uno or Nano
Check which of the pins is capable of outputting a PWM signal and you will be disappointed
Hi @beejaydub
welcome to the arduino-forum.
in programming there are millions of ways of variations to realise very different functionalities. It is unlikely that you find a code that matches 99% of what you want to have.
This means you will have to modify an existing code that you use as a base. The only way to modify a code is to learning how to code.
What you are asking for randomly switching on/off and additionally randomly fading these leds is doable on almost any kind of microcontroller but needs some additional information:
speed of fading out
minimum time until completely off
maximum time until completely off
how long shall it pause off?
how long shall it be switched on
full brightness from the very first millisecond of switching on?
or
fading "In" ?
MAX7219 calls PWM "brightness control"...
Even if I could fade the available, and flash the others I htink it would be fine. I can also change resitors to adjust brightness if need be. Side note using a nano.
Well, you can do 6 LEDs per Nano using analogWrite().
You might be able to do 6 more with software PWM.
Or you could use smart LEDs ("neopixels") (in which case you can control more than 6 with a single pin.)
Try a pseudo-PWM on the LED DIO pins, by setting the pin ON/OFF very quickly and a long time before the next transition, possibly making the LEDs appear dim, then increase the length of time the pin is ON and decrease the time between transitions.
You could try the MobaTools library. The MoToSoftLed class of the library is able to fade Leds in and out. The sketch only needs to set them on or off, the fading is done by the lib. You are not restricted to use PWM capable pins to do so.
There are different examples, but the random feature has to be added by yourself.
On AVR processors the brightness for full on and off cannot be adjusted, you have to do that by different resistors.
I can assure you that 72 PWM channels can be done with software PWM driving 74595 shift registers.
That was on a 4MHz PIC, so Arduino 16MHz should give better profiles on more channels.