commit 174a682959b54cc4994ec231e66467208130e3a9
Author: Michael Wesemann <mike@pstbx.org>
Date:   Wed Feb 20 13:34:54 2019 +0100

    initial commit

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..ad20b5f
--- /dev/null
+++ b/README.md
@@ -0,0 +1,41 @@
+# Dual magnetic stir controller
+
+## Overview
+
+This is the Arduino sketch to build a double magnetic stirrer based on 2 fans, a 1602 LCD display, a KY-040 encoder and an Arduino (e.g. Uno, Leonardo, Pro Micro).
+
+<p align="center">
+<img src="https://github.com/micworg/stir/blob/master/images/stir.jpg" width=500>
+</p>
+
+In order to put the stirrer into operation you have to change the settings in stir.ino according to your setup.
+
+## Overview of Functions
+
+All functions are controlled by the KY-040 encoder:
+
+* **Press briefly:** change between menu, stirrer 1 and stirrer 2
+* **Turn when menu is selected**: change between menu items (SPEED, BOOST, BTIME, CATCH, CTIME)
+* **Long press when menu is selected**: Lock all functions (unlock also by long press)
+* **When a stirrer is selected**:
+  * **SPEED**: turn sets speed, long press switches stirrer on or off.
+  * **BOOST**: turn sets boost speed, long press activates/deactivates the boost function (running time is shown in the display).
+  * **BTIME**: turn sets the boost time in minutes.
+  * **CATCH**: turn activates/deactivates the fishing function
+  * **CTIME**: turn sets the interwall in minutes for the fish catching function
+
+## Display Indicators:
+
+* **Bottom Left**: Menu
+* **Bottom centre/right**: Displays the set values for the stirrers depending on the selected menu item.
+* **Top Center/Right**: Displays the current stirrer speed (or 'OFF' or 'CAT' (Fishing)).
+* **Top left**: shows the remaining time of the boost function.
+
+
+## Schematics
+
+
+<p align="center">
+<img src="https://github.com/micworg/stir/blob/master/images/schematic_leonardo.png" width=500>
+<img src="https://github.com/micworg/stir/blob/master/images/schematic_uno.png" width=500>
+</p>
\ No newline at end of file
diff --git a/images/schematic_leonardo.png b/images/schematic_leonardo.png
new file mode 100644
index 0000000..fde4afc
Binary files /dev/null and b/images/schematic_leonardo.png differ
diff --git a/images/schematic_uno.png b/images/schematic_uno.png
new file mode 100644
index 0000000..ed5c212
Binary files /dev/null and b/images/schematic_uno.png differ
diff --git a/images/stir.jpg b/images/stir.jpg
new file mode 100644
index 0000000..c775dde
Binary files /dev/null and b/images/stir.jpg differ
diff --git a/stir.ino b/stir.ino
new file mode 100644
index 0000000..41c01e5
--- /dev/null
+++ b/stir.ino
@@ -0,0 +1,440 @@
+/////////////////////////////////////////////////////////////////////////////// Stir Control (mwx'2019, v1.2.4)
+#include <EEPROM.h>
+#include <LiquidCrystal_I2C.h>
+
+#define SX Serial.print 
+#define SXN Serial.println
+#define MS (long)millis()
+
+int SPEEDINC      = 50;                                                                      // speed increment
+
+int FANMIN        = 200;                                                                   // fan minimum speed
+int FANMAX        = 1000;                                                                  // fan maximum speed
+
+int RINTERVAL     = 3000;                                                                // regulation interval 
+int RDELAY        = 2000;                                                        // regulation delay on changes
+
+int CATCHSTOP     = 20000;                                                                 // catch stop period
+
+int PWM0          = 9;                                                                    // PWM pin for 1. fan
+int PWM1          = 10;                                                                   // PWM pin for 2. fan
+                                      
+int I0            = 2;                                                       // interrupt for 1. fan rpm signal
+int I1            = 3;                                                       // interrupt for 2. fan rpm signal
+                                  
+int CLK           = 5;                                                                 // clk on KY-040 encoder
+int DT            = 6;                                                                  // dt on KY-040 encoder
+int SW            = 4;                                                                  // sw on KY-040 encoder
+
+int SAVETAG       = 1004;                                                                           // save tag 
+
+LiquidCrystal_I2C lcd(0x27,16,2);                                           // LCD display (connect to SDA/SCL)
+
+int v0,b0,r0,v1,b1,r1,r,fanstate0,fanstate1;                                            // speed and regulation
+long rpmcount0,rpmcount1;                                                                        // rpm counter
+double rpm0,rpm1;                                                                                        // rpm
+
+long speedts,dt,rts,swts,bts,ox,savets,catchts0,catchts1,stop0,stop1,b0ts,b1ts;                       // timing
+int bdelay,bprocess,enclast,encval,swmode;                                                 // button processing
+char form[8],out[32],M[8];String str;                                                          // string buffer
+int OK,SAVE,LOCK,bstate0,bstate1,btime0,btime1,catch0,catch1,ctime0,ctime1,mode;
+ 
+ 
+void setup() { ////////////////////////////////////////////////////////////////////////////////////////// SETUP
+  rpmcount0=0;rpmcount1=0;rpm0=0;rpm1=0;bprocess=0;speedts=0;r0=0;r1=0;swmode=2;
+
+  Serial.begin(9600);                                                                           // start serial
+  
+  lcd.init();lcd.backlight();lcd.clear();                                                     // initialize lcd
+
+  attachInterrupt(I0,rpmint0,FALLING);                                           // setup interrupts vor rpm in
+  attachInterrupt(I1,rpmint1,FALLING);
+
+  TCCR1A=0;TCCR1B=0;TCNT1=0;                                                      // setup timer for 25 kHz PWM
+  TCCR1A = _BV(COM1A1)  // non-inverted PWM on ch. A
+         | _BV(COM1B1)  // same on ch; B
+         | _BV(WGM11);  // mode 10: ph. correct PWM, TOP=ICR1
+  TCCR1B = _BV(WGM13)   // ditto
+         | _BV(CS10);   // prescaler=1
+  ICR1   = 320;         // TOP=320
+
+  SAVE=0;                                                                           // load/initialize settings
+  if (eer(0)!=SAVETAG) {
+    v0=300;v1=300;b0=700;b1=700;btime0=30;btime1=30;catch0=0;catch1=0;ctime0=120;ctime1=120;
+      eew(0,SAVETAG);
+      save();
+  } else {
+    v0=eer(1);v1=eer(2);b0=eer(3);b1=eer(4);btime0=eer(5);btime1=eer(6);
+    catch0=eer(7);catch1=eer(8);ctime0=eer(9);ctime1=eer(10);
+  }
+
+  pinMode(PWM0,OUTPUT);pinMode(PWM1,OUTPUT);                                                   // set pin modes
+  pinMode(CLK,INPUT);pinMode(DT,INPUT);pinMode(SW,INPUT);
+
+  enclast=digitalRead(CLK);                                                                // get encoder state
+
+  fanstate0=0;fanstate1=0;OCR1A=0;OCR1B=0;                                                     // turn fans off
+
+  rts=MS;swts=MS;bts=MS;savets=MS;catchts0=MS;catchts1=MS;stop0=MS;stop1=MS;                       // set timer
+
+  bstate0=0;bstate1=0;mode=0;updatelcd();updatespeed();updatemarker();LOCK=0;             // set initial states
+}
+
+
+void loop() { //////////////////////////////////////////////////////////////////////////////////////////// LOOP
+
+  if (SAVE>0 && MS-savets>60000) {;save();SAVE=0;savets=MS;} ////////////////////////// save settings if needed
+  
+  if (catch0 && MS-catchts0>(long)ctime0*60000) { ////////////////////////////////////// check catch fish state
+    catchts0=MS;stop0=MS+CATCHSTOP;
+    updatePWM();
+  }
+  if (catch1 && MS-catchts1>(long)ctime1*60000) {
+    catchts1=MS;stop1=MS+CATCHSTOP;
+    updatePWM();
+  }
+
+  if (bstate0 && MS-b0ts>(long)btime0*60000) {;bstate0=0;mode=0;updatelcd();} /////////////// check boost state
+  if (bstate1 && MS-b1ts>(long)btime1*60000) {;bstate1=0;mode=0;updatelcd();}
+
+  if (Serial.available() > 0) { ////////////////////////////////////////////////////////// serial communication
+    str=Serial.readString();OK=0;
+
+    if (str=="info") {;serinfo();OK=1;}                                                                 // info
+    
+    if (str.substring(0,5)=="speed") {                                                   // speed <fan0> <fan1>
+      v0=sstr(str,':',1).toInt();
+      v1=sstr(str,':',2).toInt();
+      updatePWM();r0=0;r1=0;rts=MS+RDELAY;
+      SAVE++;OK=1;updatelcd();serinfo();
+    }
+
+    if (str.substring(0,6)=="bspeed") {                                                 // bspeed <fan0> <fan1>
+      b0=sstr(str,':',1).toInt();
+      b1=sstr(str,':',2).toInt();
+      updatePWM();r0=0;r1=0;rts=MS+RDELAY;
+      SAVE++;OK=1;updatelcd();updatespeed();serinfo();
+    }
+    
+    if (str.substring(0,2)=="on") {                                         // on <fan0> <fan1> (value: 0 or 1)
+      if (sstr(str,':',1).toInt()==1) {;fanstate0=1;r0=0;} else fanstate0=0;
+      if (sstr(str,':',2).toInt()==1) {;fanstate1=1;r1=0;} else fanstate1=0;
+      updatePWM();rts=MS+RDELAY;
+      SAVE++;OK=1;updatelcd();updatespeed();serinfo();
+    }
+
+    if (str.substring(0,5)=="boost") {                                   // boost <fan0> <fan1> (value: 0 or 1)
+      if (sstr(str,':',1).toInt()==1) {;rts=MS+RDELAY;bstate0=1;b0ts=MS;} else {;bstate0=0;}
+      if (sstr(str,':',2).toInt()==1) {;rts=MS+RDELAY;bstate1=1;b1ts=MS;} else {;bstate1=0;}
+      SAVE++;OK=1;updatelcd();updatespeed();serinfo();
+    }
+
+    if (str.substring(0,5)=="catch") {                                   // catch <fan0> <fan1> (value: 0 or 1)
+      if (sstr(str,':',1).toInt()==1) {;catch0=1;catchts0=MS;} else {;catch0=0;}
+      if (sstr(str,':',2).toInt()==1) {;catch1=1;catchts1=MS;} else {;catch1=0;}
+      SAVE++;OK=1;updatelcd();updatespeed();serinfo();
+    }
+    
+    if (str.substring(0,5)=="btime") {                                     // btime <fan0> <fan1> (value: 0-60)
+      btime0=sstr(str,':',1).toInt();if (btime0<0) btime0=0;if (btime0>60) btime0=60;
+      btime1=sstr(str,':',2).toInt();if (btime1<0) btime1=0;if (btime1>60) btime1=60;
+      SAVE++;OK=1;updatelcd();updatespeed();serinfo();
+    }
+    
+    if (str.substring(0,5)=="ctime") {                                   // ctime <fan0> <fan1> (value: 60-240)
+      ctime0=sstr(str,':',1).toInt();if (ctime0<60) ctime0=60;if (ctime0>240) ctime0=240;
+      ctime1=sstr(str,':',2).toInt();if (ctime1<60) ctime1=60;if (ctime1>240) ctime1=240;
+      SAVE++;OK=1;updatelcd();updatespeed();serinfo();
+    }
+
+    if (!OK) SXN("ERROR");
+  }
+
+  if (MS-rts>RINTERVAL) { ////////////////////////////////////////////////////////////////////////// regulation
+    
+    rpm0=rpmcount0/2/((MS-speedts)/1000.0)*60.0;
+    rpm1=rpmcount1/2/((MS-speedts)/1000.0)*60.0;
+
+    speedts=MS;rpmcount0=0;rpmcount1=0;
+
+    if (abs(v0-rpm0)>8) {
+      ox=1;if (abs(v0-rpm0)>20) ox=3;if (abs(v0-rpm0)>50) ox=5;
+      if (bstate0) r=b0; else r=v0;
+      if (r>rpm0) {;r0+=ox;if (r0>40) r0=40;}
+      if (r<rpm0) {;r0-=ox;if (r0<-40) r0=-40;}
+    }
+
+    if (abs(v1-rpm1)>8) {
+      ox=1;if (abs(v1-rpm1)>20) ox=3;if (abs(v1-rpm1)>50) ox=5;
+      if (bstate1) r=b1; else r=v1;
+      if (r>rpm1) {;r1+=ox;if (r1>40) r1=40;}
+      if (r<rpm1) {;r1-=ox;if (r1<-40) r1=-40;}
+    }
+    
+    if (!fanstate0) r0=0;
+    if (!fanstate1) r1=0;
+        
+    updatePWM();updatespeed();rts=MS;
+  }
+
+  bdelay=0; //////////////////////////////////////////////////////////////////////////////////// process switch
+  if (!bprocess) {
+    while (!digitalRead(SW)){
+      bdelay++;
+      delay(25);
+      bprocess=1;
+      if (bdelay>20) break;
+    }
+  }
+  
+  if (bdelay>0 && MS-bts>100) {                                                            // long button press
+    if (bdelay>20) {
+      
+      if (swmode==0 && mode==0 && !LOCK) {                                                      // fan 0 on/off
+        if (fanstate0==0) {;rts=MS+RDELAY;fanstate0=1;r0=0;updatePWM();}
+        else {;fanstate0=0;}
+        updatespeed();
+      }
+      if (swmode==1 && mode==0 && !LOCK) {                                                      // fan 1 on/off
+        if (fanstate1==0) {;rts=MS+RDELAY;fanstate1=1;r1=0;updatePWM();}
+        else {;fanstate1=0;}
+        updatespeed();
+      }
+
+      if (swmode==0 && mode==1 && !LOCK) {                                                    // boost 0 on/off
+        if (bstate0==0) {
+          rts=MS+RDELAY;bstate0=1;b0ts=MS;fanstate0=1;r0=0;updatePWM();
+        } else {;bstate0=0;}
+        updatespeed();
+      }
+      if (swmode==1 && mode==1 && !LOCK) {                                                    // boost 1 on/off
+        if (bstate1==0) {
+          rts=MS+RDELAY;bstate1=1;b1ts=MS;fanstate1=1;r1=0;updatePWM();
+        } else {;bstate1=0;}
+        updatespeed();
+      }
+
+      if (swmode==2) {                                                                           // lock/unlock
+        if (LOCK==0) LOCK=1;
+        else LOCK=0;
+        updatemarker();
+      }
+      
+      bdelay=0;
+      
+    } else if (bdelay>0 && bdelay<20 && !LOCK) {           // short button press: switch menu -> fan 0 -> fan 1
+      swmode++;if (swmode>2) swmode=0;
+      updatemarker();
+      bdelay=0;
+    }
+    
+    bts=MS;
+  }
+  if (digitalRead(SW)) bprocess=0;
+
+  encval = digitalRead(CLK); ////////////////////////////////////////////////////////////////// process encoder
+  if (encval != enclast && !LOCK) {
+    if(!encval){
+            
+      if (digitalRead(DT) != encval) {                                                                    // cw
+        if (swmode==0 && mode==0) v0+=SPEEDINC;  // fan 0 speed up
+        if (swmode==1 && mode==0) v1+=SPEEDINC;  // fan 1 speed up
+        if (swmode==0 && mode==1) b0+=SPEEDINC;  // boost 0 speed up
+        if (swmode==1 && mode==1) b1+=SPEEDINC;  // boost 1 speed up
+        if (swmode==0 && mode==2) btime0++;      // boost time 0 up
+        if (swmode==1 && mode==2) btime1++;      // boost time 1 up
+        if (swmode==0 && mode==3) catch0++;      // catch 0 on/off
+        if (swmode==1 && mode==3) catch1++;      // catch 1 on/off
+        if (swmode==0 && mode==4) ctime0+=10;    // catch time 0 up
+        if (swmode==1 && mode==4) ctime1+=10;    // catch time 1 up
+        if (swmode==2) mode++;
+      } else {                                                                                           // ccw
+        if (swmode==0 && mode==0) v0-=SPEEDINC;  // fan 0 speed down
+        if (swmode==1 && mode==0) v1-=SPEEDINC;  // fan 1 speed down
+        if (swmode==0 && mode==1) b0-=SPEEDINC;  // boost 0 speed down
+        if (swmode==1 && mode==1) b1-=SPEEDINC;  // boost 1 speed down
+        if (swmode==0 && mode==2) btime0--;      // boost time 0 down
+        if (swmode==1 && mode==2) btime1--;      // boost time 1 down
+        if (swmode==0 && mode==3) catch0--;      // catch 0 on/off
+        if (swmode==1 && mode==3) catch1--;      // catch 1 on/off
+        if (swmode==0 && mode==4) ctime0-=10;    // catch time 0 down
+        if (swmode==1 && mode==4) ctime1-=10;    // catch time 1 down
+        if (swmode==2) mode--;
+      }
+    
+      if (swmode==0 && mode==0) {;updatePWM();r0=0;rts=MS+RDELAY;}                      // apply speed change 0
+      if (swmode==1 && mode==0) {;updatePWM();r1=0;rts=MS+RDELAY;}                      // apply speed change 1
+      if (swmode==0 && mode==1) {;updatePWM();r0=0;rts=MS+RDELAY;}                // apply boost speed change 0
+      if (swmode==1 && mode==1) {;updatePWM();r1=0;rts=MS+RDELAY;}                // apply boost speed change 1
+      
+      if (swmode==0 && mode==2) {;if (btime0<0) btime0=0;if (btime0>60) btime0=60;}       // check boost time 0
+      if (swmode==1 && mode==2) {;if (btime1<0) btime1=0;if (btime1>60) btime1=60;}       // check boost time 1
+      
+      if (swmode==0 && mode==3) {;if (catch0<0) catch0=1;if (catch0>1) catch0=0;catchts0=MS;}  // check catch 0
+      if (swmode==1 && mode==3) {;if (catch1<0) catch1=0;if (catch1>1) catch1=0;catchts1=MS;}  // check catch 1
+      
+      if (swmode==0 && mode==4) {;if (ctime0<60) ctime0=60;if (ctime0>240) ctime0=240;}   // check boost time 0
+      if (swmode==1 && mode==4) {;if (ctime1<60) ctime1=60;if (ctime1>240) ctime1=240;}   // check boost time 1
+
+      if (swmode==2) {;if (mode<0) mode=4;if (mode>4) mode=0;}                               // check menu mode
+      
+      SAVE++;updatelcd();delay(50);
+    } 
+  }
+  enclast=encval;
+  
+}
+
+
+/////////////////////////////////////////////////////////////////////////////////////////////////////// SUPPORT
+
+void updatelcd() { ///////////////////////////////////////////////////////////////////////////////// update LCD
+  if (mode==0) {
+    slcd(1,1,5,"SPEED");
+    ilcd(7,1,-4,int(v0));
+    ilcd(12,1,-4,int(v1));
+  }
+  if (mode==1) {
+    slcd(1,1,5,"BOOST");
+    ilcd(7,1,-4,int(b0));
+    ilcd(12,1,-4,int(b1));
+  }
+  if (mode==2) {
+    slcd(1,1,5,"BTIME");
+    ilcd(7,1,-4,int(btime0));ilcd(12,1,-4,int(btime1));
+  }
+  if (mode==3) {
+    slcd(1,1,5,"CATCH");
+    if (catch0==0) slcd(7,1,-4,"OFF");
+    else slcd(7,1,-3,"ON");
+    if (catch1==0) slcd(12,1,-4,"OFF");
+    else slcd(12,1,-3,"ON");
+  }
+  if (mode==4) {
+    slcd(1,1,5,"CTIME");
+    ilcd(7,1,-4,int(ctime0));ilcd(12,1,-4,int(ctime1));
+  }
+}  
+  
+void updatemarker() { /////////////////////////////////////////////////////////////////// update current marker
+  slcd(0,1,1," ");
+  slcd(6,1,1," ");
+  slcd(11,1,1," ");
+  if (!LOCK) {
+    if (swmode==0) slcd(6,1,1,">");
+    if (swmode==1) slcd(11,1,1,">");
+    if (swmode==2) slcd(0,1,1,">");
+  }
+}
+
+void updatespeed() { ///////////////////////////////////////////////////////////////////////// update fan speed
+
+  slcd(1,0,5,"     ");
+  if (fanstate0) {
+    if (MS<stop0) {
+      slcd(7,0,-4,"CAT");
+    } else {
+      if (bstate0) {
+        ilcd(1,0,2, (((long)btime0*60000)-(MS-(long)b0ts))/1000/60+1);
+      } else slcd(7,0,1," ");
+      ilcd(7,0,-4,round(rpm0/5.0)*5);
+    }
+  }
+  else slcd(7,0,-4,"OFF");
+  
+  if (fanstate1) {
+    if (MS<stop1) {
+      slcd(12,0,-4,"CAT");
+    } else {
+      if (bstate1) {
+        ilcd(4,0,2, (((long)btime1*60000)-(MS-(long)b1ts))/1000/60+1);
+      } else slcd(12,0,1," ");
+      ilcd(12,0,-4,round(rpm1/5.0)*5);
+    }
+  }
+  else slcd(12,0,-4,"OFF");
+}
+
+void serinfo() { /////////////////////////////////////////////////////////////////////////// serial info output 
+  SX(fanstate0);SX(":");SX((int)(v0));SX(":");SX((int)(b0));SX(":");
+  SX(fanstate1);SX(":");SX((int)(v1));SX(":");SX((int)(b1));SX(":");
+  SX(rpm0);SX(":");SX(rpm1);SX(":");SX(r0);SX(":");SX(r1);SX(":");
+  SX(bstate0);SX(":");SX(bstate1);SX(":");SX(btime0);SX(":");SX(btime1);SX(":");
+  SX(catch0);SX(":");SX(catch1);SX(":");SX(ctime0);SX(":");SX(ctime1);SXN("");
+}
+
+void ilcd(int x,int y, int l,int v) { //////////////////////////////////////////////////// write integer to LCD
+  sprintf(form,"%%%dd",l);
+  sprintf(out,form,v);
+  lcd.setCursor(x,y);lcd.print(out);
+}
+
+void slcd(int x,int y, int l,String s) { ////////////////////////////////////////////////// write string to LCD
+  sprintf(form,"%%%ds",l);
+  sprintf(out,form,s.c_str());
+  lcd.setCursor(x,y);lcd.print(out);
+}
+
+void updatePWM() { ///////////////////////////////////////////////////////////////////// update PWM (fan speed)
+  if (v0<FANMIN) v0=FANMIN;if (v0>FANMAX) v0=FANMAX;
+  if (v1<FANMIN) v1=FANMIN;if (v1>FANMAX) v1=FANMAX;
+  if (b0<FANMIN) b0=FANMIN;if (b0>FANMAX) b0=FANMAX;
+  if (b1<FANMIN) b1=FANMIN;if (b1>FANMAX) b1=FANMAX;
+  
+  double v;
+  
+  if (fanstate0) {
+    if (MS<stop0) {
+      OCR1A=0;
+    } else {
+      if (bstate0) {
+        v=b0/(FANMAX/320.0)+r0;if (v<0) v=0;if (v>320) v=320;
+        OCR1A=v;
+      } else {
+        v=v0/(FANMAX/320.0)+r0;if (v<0) v=0;if (v>320) v=320;
+        OCR1A=v;
+      }
+    }
+  } else OCR1A=0;
+  
+  if (fanstate1) {
+    if (MS<stop1) {
+      OCR1B=0;
+    } else {
+      if (bstate1) {
+        v=b1/(FANMAX/320.0)+r1;if (v<0) v=0;if (v>320) v=320;
+        OCR1B=v; 
+      } else {
+        v=v1/(FANMAX/320.0)+r1;if (v<0) v=0;if (v>320) v=320;
+        OCR1B=v;
+      }
+    } 
+  } else  OCR1B=0;
+} 
+
+void rpmint0() {;rpmcount0++;} ///////////////////////////////////////////////////////////////// rpm interrupts
+void rpmint1() {;rpmcount1++;}
+
+int eer(int adr) {;return EEPROM.read(adr*2)+EEPROM.read(adr*2+1)*256;} /////////////////////////// read EEPROM
+
+void eew(int adr, int val) {;EEPROM.write(adr*2,val%256);EEPROM.write(adr*2+1,val/256);} /////// save to EEPROM
+
+void save() { /////////////////////////////////////////////////////////////////////////////////// save settings
+  eew(1,v0);eew(2,v1);eew(3,b0);eew(4,b1);eew(5,btime0);eew(6,btime1);
+  eew(7,catch0);eew(8,catch1);eew(9,ctime0);eew(10,ctime1);
+}
+
+String sstr(String data, char separator, int index) { ///////////////////////////////// get saperated substring
+  int found=0;
+  int si[]={0,-1};
+  int mi=data.length()-1;
+
+  for (int i=0; i<=mi && found<=index; i++) {
+    if (data.charAt(i) == separator || i == mi) {
+      found++;si[0]=si[1]+1;si[1]=(i==mi) ? i+1 : i;
+    }
+  }
+  return found > index ? data.substring(si[0], si[1]) : "";
+}
+
+/////////////////////////////////////////////////////////////////////////////////////////////////////////// END
\ No newline at end of file