c - Sketch that responds to certain commands, how is it done? -

alright have half complete arduino sketch @ moment. sketch below blink led on kegboard-mini shield if string of chars equals *{blink_flow_a}* led blinks once current sketch loaded on arduino. arduino blink repeatedly until "stop" command sent arduino. open valve, keep open until valve receives close command close valve. sketch looks following,

/*  * kegboard-serial-simple-blink07  * code public domain  *  * sketch sends receives multibyte string iphone  * , performs functions on it.  *  * examples:  * http://arduino.cc/en/tutorial/serialevent  * http://arduino.cc/en/serial/read  */   // global variables should identified _   // flow_a led  int led = 4;   // relay_a  const int relay_a = a0;   // variables sketch example  string inputstring = ""; // string hold incoming data  boolean stringcomplete = false; // whether string complete   void setup() {     serial.begin(2400); // open serial port, sets data rate 2400bps    serial.println("power on test");    inputstring.reserve(200);     pinmode(relay_a, output); }  void open_valve() {    digitalwrite(relay_a, high); // turn relay_a on  }  void close_valve() {    digitalwrite(relay_a, low); // turn relay_a off }  void flow_a_blink() {    digitalwrite(led, high); // turn led on (high voltage level)   delay(1000);              // wait 1 second   digitalwrite(led, low);   // turn led off making voltage low   delay(1000);              // wait second }  void flow_a_blink_stop() {    digitalwrite(led, low); }  void loop() {   // print string when newline arrives:   if (stringcomplete) {     serial.println(inputstring);     // clear string:     inputstring = "";     stringcomplete = false;   }    if (inputstring == "{blink_flow_a}") {     flow_a_blink();   } }  //serialevent occurs whenever new data comes in //hardware serial rx.  routine run between each //time loop() runs, using delay inside loop can delay //response.  multiple bytes of data may available.  void serialevent() {   while(serial.available()) {     // new byte:     char inchar = (char)serial.read();     // add inputstring:     inputstring += inchar;     // if incoming character newline, set flag     // main loop can it:     if (inchar == '\n') {       stringcomplete = true;     }   } } 

if makes difference on irc told me research state machines scratches head

a state machine (at it's simplest - can lots more complicated) can set of conditional statements (if/else or switch/case) behaviors based on state of variable, , change variable state. can thought of way of handling or progressing through series of conditions.

so have state of led/valve - either blinking (open) or not blinking (closed). in pseudo code here:

boolean led_state = false;  //init false/closed  void loop(){   if (checkforcorrectcommand() == true){ //     if (led_state == false){      open_valve();      led_state = true;     } else {      close_valve();      led_state = false;    }  } } 

the blinking led part should easy implement if gist of code above. checkforcorrectcommand() bit function write checking whatever input - key, serial, button, etc. should return boolean.