My first project is to light a string of papier-m??ch?? hot air balloons. I was just going to light them with some LEDs, but then I heard about the Arduino and wanted to make something more exciting. I got a starter kit from adafruit.com and got to work.
This is the first proof of concept of making the LEDs flicker. Later I???ll add a light sensor to start a sleep timer that will turn the balloons off after a half hour. Here???s the sketch that runs what you see above:/** randomly flickering LEDs*/int ledPin[] = {5, 6, 9, 10, 11}; // pwm pins onlyint ledState[5]; // last state of each ledlong randNumber;void setup() {for (int i=0; i<5; i++){ // set each led pin as an output pinMode(ledPin[i], OUTPUT); }randomSeed(analogRead(0)); // seed the rnd generator with noise from unused pinfor (int i=0; i<5; i++){ // init each led with a random value ledState[i] = random(20, 201);}}void loop(){for (int i=0; i<5; i++){ // for each led: analogWrite(ledPin[i], ledState[i]); // set the pwm value of that pin determined previously randNumber = random(-35, 41); // generate new random number and add that to the current value ledState[i] += randNumber; // that range can be tweaked to change the intensity of the flickering if (ledState[i] > 200) { // now clamp the limits of the pwm values so it remains within ledState[i] = 200; // a pleasing range as well as the pwm range } if (ledState[i] < 10) { ledState[i] = 10; }}delay(100); // the delay between changes}
Adlers-blog 