Tutorial: How to use Keypad | Text Entry Mode | Arduino

  1/*
  2    July 16, 2020
  3    This will be use to explore the use of 4x4 keypad for
  4      1. T9 text entry
  5      2. A, B, C, and D will be use for the menu operations
  6    Author: George Bantique ( TechToTinker )
  7*/
  8
  9#include "LiquidCrystal.h"
 10#include "Keypad.h"
 11
 12#define DEFAULT_DELAY 300
 13
 14const byte ROWS = 4; //four rows
 15const byte COLS = 4; //four columns
 16
 17int x = 0;                // Holds the LCD x position
 18int y = 0;                // Holds the LCD y position
 19int minValue = 0;         // Lower character location for T9 text entry
 20int maxValue = 0;         // Max character location for T9 text entry
 21int keyPressTime = 100;   // Number of loops check of the key
 22String msg = "";          // Holds the created message
 23String num = "";          // Holds the mobile number
 24String alpha = "!@_$%?1 ABC2 DEF3 GHI4 JKL5 MNO6 PQRS7 TUV8 WXYZ9 * 0# "; // Characters for T9 text entry
 25
 26char hexaKeys[ROWS][COLS] = { // Character matrix for the keypad
 27  {'1', '2', '3', 'A'},
 28  {'4', '5', '6', 'B'},
 29  {'7', '8', '9', 'C'},
 30  {'*', '0', '#', 'D'}
 31};
 32
 33byte rowPins[ROWS] = {7, 6, 5, 4};        // pin assignments for keypad rows
 34byte colPins[COLS] = {3, 2, 1, 0};        // pin assignments for keypad columns
 35
 36Keypad customKeypad = Keypad( makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS);
 37LiquidCrystal lcd(13, 12, 11, 10, 9, 8);  // pin assignments for LCD
 38
 39byte charUp[8] = {  // arrow up character for LCD
 40  B00100,
 41  B01110,
 42  B11111,
 43  B00000,
 44  B00000,
 45  B00000,
 46  B00000,
 47  B00000
 48};
 49byte charDown[8] = {  // arrow down character for LCD
 50  B00000,
 51  B00000,
 52  B00000,
 53  B00000,
 54  B00000,
 55  B11111,
 56  B01110,
 57  B00100
 58};
 59byte charUpDown[8] = {  // arrow up and down character for LCD
 60  B00100,
 61  B01110,
 62  B11111,
 63  B00000,
 64  B00000,
 65  B11111,
 66  B01110,
 67  B00100
 68};
 69
 70byte menuLevel = 0;     // Level 0: no menu display, display anything you like
 71                        // Level 1: display main menu
 72                        // Level 2: display sub menu
 73                        // Level 3: display sub menu of sub menu
 74byte menu = 1;          // holds the menu level
 75byte sub = 1;           // holds the sub menu level
 76
 77
 78void setup()
 79{
 80  lcd.begin(16, 2);               // initialized the LCD as 16 characters with 2 lines
 81  lcd.createChar(0, charUp);      // arrow up character
 82  lcd.createChar(1, charDown);    // arrow down character
 83  lcd.createChar(2, charUpDown);  // arrow up and down character
 84  updateLevel_0();                // display the HOME screen
 85}
 86
 87void loop() {
 88  // Process the keys
 89  processkey();
 90
 91  // Do other stuffs here
 92  
 93}
 94
 95void processkey() {
 96  char key = customKeypad.getKey();
 97  if (isAlpha(key)) {   // check if key press is a letter
 98    processKeys(key);   // process it according to keys
 99  } 
100}
101
102void parseKey(int minValue, int maxValue, char keyPress) {
103  int ch = minValue;
104  char key = keyPress;
105  if (keyPress == '*') {              // if *, means backspace
106    if ( (x > 0) || (y > 0) ) {       // prevent backspace when no character yet
107      x = x - 1;                      // go back to previous character position
108      lcd.setCursor(x,y);             // set the new lcd position
109      lcd.print("*");                 // write *, which means for editing
110      msg.remove(msg.length() - 1);   // remove the last character from the string
111    }
112  } else {
113    for (int i = 0; i < keyPressTime; i++) {
114      if (key == keyPress) {          // make sure that same key is press
115        lcd.setCursor(x, y);          // set the lcd position
116        lcd.print(alpha[ch]);         // print the character according to the character position
117        ch++;                         // increment character position
118        if (ch > maxValue) {          // if the character counter reached the max value
119          ch = minValue;              // reset to min value
120          i = 0;                      // reset the loop counter
121        }
122      }
123      key = customKeypad.getKey();  // get the keypress
124      delay(10);                    // delay for some time
125    }
126    x++;                    // increment the x position
127    msg += alpha[ch - 1];   // add the character to the variable msg
128    if (x > 15) {           // if the lcd reached the rightmost position
129      y = 1;                // then wrap to the next line
130      x = 0;                // in first character in the left              
131    }
132  }
133}
134
135void enterMSG() {
136  char key;       
137  lcd.clear();  // clear the LCD display
138  x = 0;        // init the x position to zero
139  y = 0;        // init the y position to zero
140  msg = "";     // clear the msg variable
141  
142  do {
143    key = customKeypad.getKey();
144    if        (key == '1') {    // if a key is pressed, 
145      parseKey(0, 7, key);        // compare it to the alpha string array
146    } else if (key == '2') {
147      parseKey(8, 12, key);
148    } else if (key == '3') {
149      parseKey(13, 17, key);
150    } else if (key == '4') {
151      parseKey(18, 22, key);
152    } else if (key == '5') {
153      parseKey(23, 27, key);
154    } else if (key == '6') {
155      parseKey(28, 32, key);
156    } else if (key == '7') {
157      parseKey(33, 38, key);
158    } else if (key == '8') {
159      parseKey(39, 43, key);
160    } else if (key == '9') {
161      parseKey(44, 49, key);
162    } else if (key == '0') {
163      parseKey(52, 54, key);
164    } else if (key == '*') {
165      parseKey(50, 51, key);
166    } else if (key == '#') {
167      // do nothing
168    }
169  } while (key != '#');       // exit the loop when # is pressed
170
171  lcd.setCursor(0, 0);        // these are for verification only
172  lcd.print("created msg");   // feel free to modify it and
173  lcd.setCursor(0, 1);        // adapt to your specific requirements
174  lcd.print(msg);
175  delay(2000);
176}
177
178void enterNUM() {
179  char key;
180  lcd.clear();
181  x = 0;
182  y = 0;
183  num = "";
184  do {
185    key = customKeypad.getKey();
186    if (isDigit(key)) {                 // verify if the key press is a number
187      num = num + key;
188      lcd.setCursor(x,y);
189      lcd.print(key);                   // print it to the lcd
190      x++;                              // increment the x position
191      if (x > 15)                       // if the lcd reached the rightmost position
192      {                                 // then wrap to the next line
193        x = 0;
194        y = 1;
195      }
196    } else {                              // key press is not a number
197      if (key == '*') {                   // if *, means backspace
198        if ( (x > 0) || (y > 0) ) {       // prevent backspace when no character yet
199          x = x - 1;                      // go back to previous character position
200          lcd.setCursor(x,y);             // set the new lcd position
201          lcd.print("*");                 // write *, which means for editing
202          num.remove(num.length() - 1);   // remove the last character from the string
203        }
204      }
205    }
206  } while (key != '#');                   // exit the loop when # is pressed
207                                          // means entering number is complete
208  lcd.setCursor(0, 0);
209  lcd.print("created num");
210  lcd.setCursor(0, 1);
211  lcd.print(num);
212  delay(2000);
213}
214
215void sendSMS() {            // this is for demonstration only
216                            // you need to modify this and adapt
217                            // to your specific application
218  lcd.clear();
219  lcd.print("Sending SMS");
220  delay(500);
221  lcd.clear();
222  lcd.print("Done Sending");
223  delay(500);
224}
225
226void processKeys(char keyPressed) {
227  switch (menuLevel) {
228    case 0:                     // Level 0, home screen
229      switch ( keyPressed ) {
230        case 'D':               // Enter
231          menu = 1;
232          menuLevel = 1;        // go to main menu
233          updateLevel_1();      // show main menu
234          delay(DEFAULT_DELAY);
235          break;
236        case 'A': // Up
237          break;
238        case 'B': // Down
239          break;
240        case 'C': // Back
241          menuLevel = 0;        // go to home screen
242          updateLevel_0();      // show home screen
243          delay(DEFAULT_DELAY);
244          break;
245        default:
246          break;
247      }
248      break;
249    case 1:                     // Level 1, main menu
250      switch ( keyPressed ) {
251        case 'D':               // Enter
252          sub = 1;
253          menuLevel = 2;        // go to sub menu
254          updateLevel_2();      // show sub menu
255          delay(DEFAULT_DELAY);
256          break;
257        case 'A':               // Up
258          menu--;
259          updateLevel_1();      // show main menu
260          delay(DEFAULT_DELAY);
261          break;
262        case 'B':               // Down
263          menu++;
264          updateLevel_1();      // show main menu
265          delay(DEFAULT_DELAY);
266          break;
267        case 'C': // Back
268          menuLevel = 0;        // hide menu, go back to level 0
269          updateLevel_0();      // show home screen
270          delay(DEFAULT_DELAY);
271          break;
272        default:
273          break;
274      }
275      break;
276    case 2:                     // Level 2, sub menu
277      switch ( keyPressed ) {
278        case 'D':               // Enter
279          if        (sub == 1) {  // Create SMS
280            lcd.clear();
281            lcd.print("Enter message");
282            delay(1000);
283            enterMSG();
284            delay(500);
285            lcd.clear();
286            lcd.print("Enter number");
287            delay(500);
288            enterNUM();
289            menuLevel = 2;        // go to sub menu
290            updateLevel_2();      // show sub menu
291          } else if (sub == 2) {  // Send SMS
292            sendSMS();
293            menuLevel = 2;        // go to sub menu
294            updateLevel_2();      // show sub menu
295          } else if (sub == 3) {  // Read SMS
296            menuLevel = 3;        // go to sub menu of sub menu
297            updateLevel_3();      // show sub menu of sub menu
298          } else if (sub == 4) {  // Delete SMS
299            executeAction();
300            delay(1000);
301            menuLevel = 2;        // go to sub menu
302            updateLevel_2();      // show sub menu
303          }
304          delay(DEFAULT_DELAY);
305          break;
306        case 'A':               // Up
307          sub--;
308          updateLevel_2();
309          delay(DEFAULT_DELAY);
310          break;
311        case 'B':               // Down
312          sub++;
313          updateLevel_2();      // show main menu
314          delay(DEFAULT_DELAY);
315          break;
316        case 'C':               // Back
317          menuLevel = 1;        // go back to level 1
318          updateLevel_1();      // show main menu
319          delay(DEFAULT_DELAY);
320          break;
321        default:
322          break;
323      }
324      break;
325    case 3:                     // Level 3, sub menu of sub menu
326      switch ( keyPressed ) {
327        case 'D':               // Enter
328          //menuLevel = 2;        // go back to level 2
329          //updateLevel_2();      // show sub menu
330          delay(DEFAULT_DELAY);
331          break;
332        case 'A':               // Up
333          updateLevel_3();      // show sub menu
334          delay(DEFAULT_DELAY);
335          break;
336        case 'B':               // Down
337          updateLevel_3();      // show sub menu
338          delay(DEFAULT_DELAY);
339          break;
340        case 'C':               // Back
341          menuLevel = 2;        // go back to main menu
342          updateLevel_2();      // show main menu
343          delay(DEFAULT_DELAY);
344          break;
345        default:
346          break;
347      }
348      break;
349    default:
350      break;
351  }
352}
353
354void updateLevel_0() {
355  lcd.clear();
356  lcd.println("Keypad TextEntry");
357  lcd.setCursor(0, 1);
358  lcd.println("  - D for menu  ");
359}
360
361void updateLevel_1 () {
362  switch (menu) {
363    case 0:
364      menu = 1;
365      break;
366    case 1:
367      lcd.clear();
368      lcd.print(">Messages       ");
369      lcd.setCursor(0, 1);
370      lcd.print(" Contacts       ");
371      lcd.setCursor(15, 1);
372      lcd.write((byte)1);     // down arrow
373      break;
374    case 2:
375      lcd.clear();
376      lcd.print(" Messages       ");
377      lcd.setCursor(0, 1);
378      lcd.print(">Contacts       ");
379      lcd.setCursor(15, 1);
380      lcd.write((byte)2);     // up and down arrow
381      break;
382    case 3:
383      lcd.clear();
384      lcd.print(" Contacts       ");
385      lcd.setCursor(0, 1);
386      lcd.print(">Others         ");
387      lcd.setCursor(15, 1);
388      lcd.write((byte)0);     // up arrow
389      break;
390    case 4:
391      menu = 3;
392      break;
393  }
394}
395
396void updateLevel_2 () {
397  switch (menu) {
398    case 0:
399      break;
400    case 1:                                 // Messages
401      switch (sub) {
402        case 0:
403          break;
404        case 1:
405          lcd.clear();
406          lcd.print(" Messages:      ");
407          lcd.setCursor(0, 1);
408          lcd.print("  Create SMS    ");
409          lcd.setCursor(15, 1);
410          lcd.write((byte)1);     // down arrow
411          break;
412        case 2:
413          lcd.clear();
414          lcd.print(" Messages:      ");
415          lcd.setCursor(0, 1);
416          lcd.print("  Send SMS      ");
417          lcd.setCursor(15, 1);
418          lcd.write((byte)2);     // up and down arrow
419          break;
420        case 3:
421          lcd.clear();
422          lcd.print(" Messages:      ");
423          lcd.setCursor(0, 1);
424          lcd.print("  Read SMS      ");
425          lcd.setCursor(15, 1);
426          lcd.write((byte)2);     // up and down arrow
427          break;
428        case 4:
429          lcd.clear();
430          lcd.print(" Messages:      ");
431          lcd.setCursor(0, 1);
432          lcd.print("  Delete SMS    ");
433          lcd.setCursor(15, 1);
434          lcd.write((byte)0);     // up arrow
435          break;
436        default:
437          break;
438      }
439      break;
440    case 2:                                 // Relay 2
441      switch (sub) {
442        case 0:
443          break;
444        case 1:
445          lcd.clear();
446          lcd.print(" Contacts:      ");
447          lcd.setCursor(0, 1);
448          lcd.print("  Save Contacts ");
449          lcd.setCursor(15, 1);
450          lcd.write((byte)1);     // down arrow
451          break;
452        case 2:
453          lcd.clear();
454          lcd.print(" Contacts:      ");
455          lcd.setCursor(0, 1);
456          lcd.print("  Edit Contacts ");
457          lcd.setCursor(15, 1);
458          lcd.write((byte)2);     // up and down arrow
459          break;
460        case 3:
461          lcd.clear();
462          lcd.print(" Contacts:      ");
463          lcd.setCursor(0, 1);
464          lcd.print("  Del Contacts");
465          lcd.setCursor(15, 1);
466          lcd.write((byte)0);     // up arrow
467          break;
468        default:
469          break;
470      }
471      break;
472    case 3:                               // Relay 3
473      switch (sub) {
474        case 0:
475          break;
476        case 1:
477          lcd.clear();
478          lcd.print(" Others:        ");
479          lcd.setCursor(0, 1);
480          lcd.print("  Send AT       ");
481          lcd.setCursor(15, 1);
482          lcd.write((byte)1);     // down arrow
483          break;
484        case 2:
485          lcd.clear();
486          lcd.print(" Others:        ");
487          lcd.setCursor(0, 1);
488          lcd.print("  Send ATA      ");
489          lcd.setCursor(15, 1);
490          lcd.write((byte)2);     // up and down arrow
491          break;
492        case 3:
493          lcd.clear();
494          lcd.print(" Others:        ");
495          lcd.setCursor(0, 1);
496          lcd.print("  Send ATH      ");
497          lcd.setCursor(15, 1);
498          lcd.write((byte)0);     // up arrow
499          break;
500        default:
501          break;
502      }
503      break;
504    case 4:
505      sub = 3;
506      break;
507  }
508}
509
510void updateLevel_3 () {
511  switch (menu) {
512    case 0:
513      break;
514    case 1:
515      lcd.clear();
516      lcd.print(" Relay 1:");
517      lcd.setCursor(0, 1);
518      lcd.print("  Val 1 = ");
519      break;
520    case 2:
521      lcd.clear();
522      lcd.print(" Relay 2:");
523      lcd.setCursor(0, 1);
524      lcd.print("  Val 2 = ");
525      break;
526    case 3:
527      lcd.clear();
528      lcd.print(" Relay 3:");
529      lcd.setCursor(0, 1);
530      lcd.print("  Val 3 = ");
531      break;
532    case 4:
533      sub = 3;
534      break;
535  }
536}
537
538void executeAction () {
539  switch (menu) {
540    case 0:
541      break;
542    case 1:
543      lcd.clear();
544      lcd.print(" Executing # 1");
545      break;
546    case 2:
547      lcd.clear();
548      lcd.print(" Executing # 2");
549      break;
550    case 3:
551      lcd.clear();
552      lcd.print(" Executing # 3");
553      break;
554    case 4:
555      sub = 3;
556      break;
557  }
558}