initially adding files

README.md

@@ -1,3 +1,12 @@
 # lcd2serial
+Reads out a 7-segment lcd display and sends the value via serial.
 
-Reads out a 7-segment lcd display and send the value via serial.
+## How to port another display?
+Analyse the display pins. You can use the ProMicro as a logic analyzer, to find the relevant segment pins and the common pins.
+You can use the information provided here: https://lowpowerlab.com/forum/projects/moteino-kitchen-scale/
+To use the Pro Micro together with PulseView you can use this repository: https://github.com/gillham/logic_analyzer 
+For more Information on LCD display consult: http://awawa.hariko.com/avr_lcd_drive_en.html 
+
+## possible improvements
+- error handlich of the serial connection. (If screen is kill in operation. The microcontroller needs a restart to reset the serial connection)
+- handle all 4 digits by the print_digit() function.

intermediate-examples

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+##
+#  This is, what the scale puts out when using the print_segments() function
+##
+#   545g  695g
+
+8: 1111  1111
+9: 1111  1111
+A: 0010  0000
+B: 0101  0101
+C: 0011  0010
+D: 1001  0001
+E: 0000  0010
+F: 0101  0101
+
+##
+#  The raw output of the arduino as some kind of logic analyser looks like this
+##
+# 0g 
+ 
+0: 10001110000001111111000111000111000000111111000111000111
+1: 
+2: 
+3: 01110001110001111000111000111000111000111000111000111000
+4: 01110001110001111000111000111000111000111000111000111000
+5: 01110001111110000000111000111000111111000000111000111000
+6: 01110001110001111000111000111000111000111000111000111000
+7: 01110001110001111000111000111000111000111000111000111000
+8: 01110001110001111000111000111000111000111000111000111000
+9: 01110001110001111000111000111000111000111000111000111000
+A: 01110001110001111000111000111000111000111000111000111000
+B: 
+C: 
+D: 
+E: 
+F: 
+
+
+# 45g
+ 
+0: 00111111000111000111000000111111000111000011100000011111
+1: 
+2: 
+3: 11000111000000111000111111000111000000111100011111100011
+4: 00111000111000111000111000111000111000111100011100011100
+5: 11000000111000111000111111000000111000111100011111100000
+6: 00111000111000111000111000111000111000111100011100011100
+7: 00111000111000111000111000111000111000111100011100011100
+8: 00111000111000111000111000111000111000111100011100011100
+9: 00111000111000111000111000111000111000111100011100011100
+A: 00111000111000111000111000111000111000111100011100011100
+B: 
+C: 
+D: 
+E: 
+F: 

lcd2serial.ino

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+/*
+  reads out a lcd display
+  based on:
+  https://lowpowerlab.com/forum/projects/moteino-kitchen-scale/
+
+  An Arduino Pro Micro was used first as a simple logic analyser,
+  to find the common pins and the segment pins. See the other sketch.
+  Later the same arduino was put with this sketch inside the scale to provide
+  serial output via usb.
+  
+  This paricular display is part of a transtek kitchen scale
+  (pcb label: tsk759)
+
+  The connector in numbered like this
+
+      ----top border of the board----
+
+    0   2   4   6   8   10   12   14
+      1   3   5   7   9   11   13   15
+
+  Pins 0 to 3 are the common pins, but since they are phase shifted by 90° only one
+  is needed.
+
+  Only Pins 8 to 15 carry useful information. All others are ignored.
+  
+*/
+
+byte samples[2][56];
+
+// lcd mapping
+int seg1[2] = { PINB2, PINB6 };
+int seg2[2] = { PINB4, PINB3 };
+int seg3[2] = { PINB2, PINB6 };
+int seg4[2] = { PINB2, PINB6 };
+
+void setup() {
+  Serial.begin(115200);
+}
+
+void loop() {
+ get_samples();  // reads out the registers
+ if (Serial.read() > 0) {
+  int pulse = get_pulse();
+  //print_segments(pulse);
+  print_4digit(pulse);
+  print_3digit(pulse);
+  print_digit(pulse, seg2);
+  print_digit(pulse, seg1); 
+  Serial.println();
+ }
+}
+
+void get_samples() {
+  int f=0;
+  while (f<56) {
+    samples[0][f] = PINB;
+    samples[1][f] = PIND;
+    delayMicroseconds(333);  // = 1/3 ms. three samples in 1ms, which is the approximate pulse width.
+    f++;
+  }
+}
+
+// try to find the position, where the control signal triggers
+// looking for a sequence of more than four ones seams sufficient
+int get_pulse() {
+  int n = 0; 
+  int f = 0;
+  while (f<30) {
+    if ((samples[1][f]& (1 << PIND3))) {
+      n++;
+      if (n>4) break; 
+    }
+    else n=0;
+    f++; 
+  }
+  return f - 3;  // sets the index in the first 1ms of the trigger event
+}
+
+void print_digit(int start, int seg[]) {
+  byte digit = InterpretSevenSegmentSet(
+          samples[0][start + 18]&(1<<seg[0]), // A or D
+          samples[0][start + 6]&(1<<seg[1]), // B     
+          samples[0][start + 12]&(1<<seg[1]), // C
+          samples[0][start]&(1<<seg[1]),  // A or D
+          samples[0][start + 12]&(1<<seg[0]), // E
+          samples[0][start]&(1<<seg[0]), // F
+          samples[0][start + 6]&(1<<seg[0]) // G
+          );
+  if (digit == 255) return;
+  else Serial.print(digit, DEC);
+}
+
+void print_4digit(int start) {
+ // print 4th digit
+ // B1 is 8
+ // D4 is 9
+  byte digit = InterpretSevenSegmentSet(
+          samples[0][start + 18]&(1<<PINB1), // A or D
+          samples[1][start + 6]&(1<<PIND4), // B     
+          samples[1][start + 12]&(1<<PIND4), // C
+          samples[1][start]&(1<<PIND4),  // A or D
+          samples[0][start + 12]&(1<<PINB1), // E
+          samples[0][start]&(1<<PINB1), // F
+          samples[0][start + 6]&(1<<PINB1) // G
+          );
+  if (digit == 255) return;
+  else Serial.print(digit, DEC);
+}
+
+void print_3digit(int start) {
+ // print 3rd digit
+ // D7 is A
+ // B5 is B
+  byte digit = InterpretSevenSegmentSet(
+          samples[1][start + 18]&(1<<PIND7), // A or D
+          samples[0][start + 6]&(1<<PINB5), // B //    
+          samples[0][start + 12]&(1<<PINB5), // C //
+          samples[0][start]&(1<<PINB5),  // A or D
+          samples[1][start + 12]&(1<<PIND7), // E //
+          samples[1][start]&(1<<PIND7), // F
+          samples[1][start + 6]&(1<<PIND7) // G
+          );
+  if (digit == 255) return;
+  else Serial.print(digit, DEC);
+}
+
+void print_2digit(int start) {
+ // print 2nd digit
+ // B4 is C
+ // B3 is D
+  byte digit = InterpretSevenSegmentSet(
+          samples[0][start + 18]&(1<<PINB4), // A or D
+          samples[0][start + 6]&(1<<PINB3), // B //    
+          samples[0][start + 12]&(1<<PINB3), // C //
+          samples[0][start]&(1<<PINB3),  // A or D
+          samples[0][start + 12]&(1<<PINB4), // E //
+          samples[0][start]&(1<<PINB4), // F
+          samples[0][start + 6]&(1<<PINB4) // G
+              );
+  Serial.print(digit, DEC);
+}
+
+void print_1digit(int start) {
+ // print 1st digit
+ // B2 is E
+ // B6 is F
+  byte digit = InterpretSevenSegmentSet(
+          samples[0][start + 18]&(1<<PINB2), // A or D
+          samples[0][start + 6]&(1<<PINB6), // B //    
+          samples[0][start + 12]&(1<<PINB6), // C //
+          samples[0][start]&(1<<PINB6),  // A or D
+          samples[0][start + 12]&(1<<PINB2), // E //
+          samples[0][start]&(1<<PINB2), // F
+          samples[0][start + 6]&(1<<PINB2) // G
+              );
+  Serial.print(digit, DEC);
+}
+
+
+/*
+  attention! in this decision tree  '1' represents off-segments
+  maybe you have to inverse it.
+
+  for a given digit, we have:
+    A
+  F   B
+    G 
+  E   C
+    D
+  then, the algorithm is:
+ */
+byte InterpretSevenSegmentSet(byte A, byte B, byte C, byte D, byte E, byte F, byte G ) {
+  byte digit;
+  if(E) {
+    if(F) {
+      if(A) {
+        if(B) digit = 0xff; // off
+        else {
+          if(D) digit = 1;
+          else  digit = 7;
+        }
+      }
+      else  digit = 3;    
+    }
+    else {
+      if(A) digit = 4;
+      else {   
+        if(B) digit = 5;
+        else  digit = 9;
+      }
+    }
+  }
+  else { 
+      if(B) {
+        if(C)  {
+          if(A) digit = 114; // "r"
+          else  digit = 69;  // "E"
+        } 
+        else digit = 6;     
+        }
+      else { 
+        if(G) digit = 0;
+        else {
+          if(C) digit = 2;
+          else  digit = 8;      
+        }
+      }
+    }    
+ return digit;
+}
+
+// this is only needed once to map the pins correcly when using this script for another display
+// here the case index corresponds to the number of the pad at the display to make mapping easier. 
+void print_segments(int start) {
+int i=2;
+  while(i<16) {
+    int f = start;
+    Serial.print(i, HEX); Serial.print(": ");
+    while (f< (start + 23))
+    {
+    switch(i) {
+      case 9:  if( (samples[1][f]& (1 << PIND4))) Serial.print("1"); else Serial.print("0"); break;
+      case 10: if( (samples[1][f]& (1 << PIND7))) Serial.print("1"); else Serial.print("0"); break;
+      case 12:  if( (samples[0][f]& (1 << PINB4))) Serial.print("1"); else Serial.print("0"); break;
+      case 11: if( (samples[0][f]& (1 << PINB5))) Serial.print("1"); else Serial.print("0"); break;
+      case 15:  if( (samples[0][f]& (1 << PINB6))) Serial.print("1"); else Serial.print("0"); break;
+      case 14:  if( (samples[0][f]& (1 << PINB2))) Serial.print("1"); else Serial.print("0"); break;
+      case 13:  if( (samples[0][f]& (1 << PINB3))) Serial.print("1"); else Serial.print("0"); break;
+      case 8:  if( (samples[0][f]& (1 << PINB1))) Serial.print("1"); else Serial.print("0"); break;
+    }
+    f = f + 6;
+    }
+    Serial.println();
+    i++;
+  }
+}