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Always interested in offers/projects/new ideas. Eclectic experience in fields like: numerical computing; Python web; Java enterprise; functional languages; GPGPU; SQL databases; etc. Based in Santiago, Chile; telecommute worldwide. CV; email.

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My Arduino Programs

From: andrew cooke <andrew@...>

Date: Sat, 19 Oct 2013 21:40:18 -0300

Took and Arduino course today.  It's incredibly simple / easy (you really
don't need a course - just buy one, read, install and run
the software, and play at flashing on and off the LED)

Anyway, here are some example programs.  I was about to close the windows and
wasn't sure where to save them...

This one flashes the built-in LED with the bit pattern in ASCII "andrew".  If
you connect up a second LED (with series resistor) to O/P 12 then it is in

  #define led 13
  #define other 12

  char *name = "andrew";
  long interval = 100;

  void setup() {                
    pinMode(led, OUTPUT);
    pinMode(other, OUTPUT);

  void loop() {
    for (int i = 0; i < strlen(name); ++i) {
      int bit = 1;
      for (int j = 0; j < 8; ++j) {
	if (bit & *(name+i)) {
	  digitalWrite(led, HIGH);
	  digitalWrite(other, LOW);
	} else {
	  digitalWrite(led, LOW);
	  digitalWrite(other, HIGH);
	bit <<= 1;

The above couples the flashing to the main loop, which is a nuisance if you
want to do multiple things in parallel with different timing / rates.  So the
next program decouples that and flashes the two LEDs at different

  #define led1 13
  #define led2 12
  int value1 = HIGH, value2 = LOW;
  long interval1 = 300, prevMillis1;
  long interval2 = 400, prevMillis2;

  void setup() {
    prevMillis1 = millis();
    pinMode(led1, OUTPUT);
    prevMillis2 = millis();
    pinMode(led2, OUTPUT);

  void loop() {
    if (millis() - prevMillis1 > interval1) {
      value1 = !value1;
      prevMillis1 = millis();
      digitalWrite(led1, value1);
    if (millis() - prevMillis2 > interval2) {
      value2 = !value2;
      prevMillis2 = millis();
      digitalWrite(led2, value2);

Finally, a program that reads from the analog input and varies the LED
flashing.  I eventually had this so that a POT controlled basic rate, but a
light-sensitive resistor could reduce the rate and a push switch fix the LED
permanently on.

The serial output lets you see what range of values are being read so that you
can adjust the mapping approrpiately.

  int ledPin = 13;
  int potPin = A3;
  int potVal;
  int period = 500;

  void setup() {
    pinMode(ledPin, OUTPUT);

  void loop() {
    potVal =  analogRead(potPin);

    potVal = constrain(map(potVal, 400, 600, 0, period), 0, period);
    digitalWrite(ledPin, HIGH);
    digitalWrite(ledPin, LOW);

Course was at Santiago MakerSpace - - who have a
couple of 3D printers (never seen one before in the flesh).


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