Randomisation

Hi everyone, my question is simple-I have two LED-s hooked up to the arduino and I want them to light up one at a time, but without order.

I'm trying to make something like the SlamMan

Former Member over 14 years ago

You might be able to use one of the pins as an analog pin, have it be a floating pin (nothing attached) and read the value of that pin. Since it is floating, you might get a pretty random value, which you can then use to determine if you want the LEDs on or off, or use two pins for two "random" sources. It could also be that depending on how the analog to digital conversion works, this may not be useful at all, that is you might get 1 sudo-random read, and then 0 for the rest. Just a thought. Don't know if it would work.
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dirtdiver over 14 years ago in reply to Former Member

this might work, but I want to add delay (one led lights up for 1sec, then the other one-for 1 sec...)
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Former Member over 14 years ago in reply to dirtdiver

A quick google search gives me this code:

long randNumber;

void setup(){
  Serial.begin(9600);

  // if analog input pin 0 is unconnected, random analog
  // noise will cause the call to randomSeed() to generate
  // different seed numbers each time the sketch runs.
  // randomSeed() will then shuffle the random function.
  randomSeed(analogRead(0));
}

void loop() {
  // print a random number from 0 to 299
  randNumber = random(300);
  Serial.println(randNumber);  

  // print a random number from 10 to 19
  randNumber = random(10, 20);
  Serial.println(randNumber);

  delay(50);
}

from http://www.arduino.cc/en/Reference/Random

You should be able to use that to easily rig up a randomiser for lighting LEDs..

Former Member over 14 years ago in reply to Former Member

That's a much better idea.
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vivamort over 14 years ago

There is a library function called TrueRandom for the arduino which I used in my last project. Its using the same principle but with a lot more bits rather than a single value like above so should be more random in results. a Quick google search will find it. You can then use the randomizer as an offset for the delay to create any time delays you wish.
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