Description
The Kimat One Wire Keypad module instantly simplifies
the implementation of a 4×4 or 3×4 keypad matrix. It
uses just one analog pin as opposed to 7 or 8 pins
without this module. It utilizes an array or resistors
carefully chosen to allow unique voltage output for
each keypress. It is then read by the
microcontroller/Arduino ADC (analog) pins for
decoding.
Usage is very simple:
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 |
/*************************************************************************** Example Code using the Kimat One Wire Keypad. Please download the library from https://github.com/AndrewMascolo/OnewireKeypad This software is free provided that this notice is not removed and proper attribution is accorded to Layad Circuits and its Author(s). Layad Circuits invests resources in producing free software. By purchasing Layad Circuits' products or utilizing its services, you support the continuing development of free software for all. The Saleng Mobile Robot Shield is designed and made by Layad Circuits. By supporting our products, you support local innovation and share in the movement to spur local ingenuity. Author(s): C.D.Malecdan for Layad Circuits Electronics Engineering Revision: 1.0 - 2017/09/27 - initial release Layad Circuits Electronics Engineering Supplies and Services B314 Lopez Bldg., Session Rd. cor. Assumption Rd., Baguio City, Philippines www.layadcircuits.com general: info@layadcircuits.com sales: sales@layadcircuits.com +63-916-442-8565 ***************************************************************************/ #include <OnewireKeypad.h> char KEYS[] = { '1', '2', '3', 'A', '4', '5', '6', 'B', '7', '8', '9', 'C', '*', '0', '#', 'D' }; OnewireKeypad <Print, 16 > KP2(Serial, KEYS, 4, 4, A0, 4700, 1000, 10000, ExtremePrec ); void setup () { Serial.begin(115200); // This method is set in the constructor with a default value of 5.0 // You only need to include this method if your Arduino is not supplying 5v to // the keypad. ie. ~4.7v or even with 3.3v Arduino boards too. //KP2.SetKeypadVoltage(5.0); KP2.SetKeypadVoltage(4.95); } void loop() { if ( char key = KP2.Getkey() ) { switch (KP2.Key_State()) { case PRESSED: Serial << "Key: " << key << " State: "; Serial.println("PRESSED"); break; case RELEASED: Serial << "Key: " << key << " State: "; Serial.println("RELEASED"); break; case HELD: Serial << "Key: " << key << " State: "; Serial.println("HOLDING"); break; } } } |
NOTE: As of this writing, newer updates to the library may cause issues with this module. As a simpler alternative, you may use the following code that does not require a library. This code processes the raw data from the analog pin, categorized it and display the corresponding key pressed. The values inside keypress() should be checked if it works for your particular devices (Arduino and Keypad).
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 |
byte PIN_KEYPAD = A0; // may be changed to any analog pin int val; char key; char keypress() { char k = NULL; val = 0; for(byte i=0;i<10;i++) { val += analogRead(PIN_KEYPAD); } val/=10; //Serial.println(val); //Uncomment to show raw values // the integer values here may be edited according to your specific devices. if(val>=1018 && val<= 1023) k = '1'; else if(val>=926 && val<= 930) k = '2'; else if(val>=848 && val<= 852) k = '3'; else if(val>=782 && val<= 788) k = 'A'; else if(val>=782 && val<= 788) k = 'A'; else if(val>=680 && val<= 699) k = '4'; else if(val>=648 && val<= 654) k = '5'; else if(val>=608 && val<= 615) k = '6'; else if(val>=574 && val<= 582) k = 'B'; else if(val>=519 && val<= 529) k = '7'; else if(val>=497 && val<= 505) k = '8'; else if(val>=474 && val<= 481) k = '9'; else if(val>=455 && val<= 460) k = 'C'; else if(val>=420 && val<= 426) k = '*'; else if(val>=403 && val<= 411) k = '0'; else if(val>=387 && val<= 395) k = '#'; else if(val>=373 && val<= 380) k = 'D'; return k; } void setup() { Serial.begin(115200); } void loop() { key = keypress(); // pass here as frequent as possible if(key) Serial.println(key); // if a key is pressed (key is not Null), then print on Serial monitor } |
The code is also downloadable from our github repository here.
Demo Video:
Downloads:
