AnalogKeypad

Library for (Robotdyn) 4x4 and 4x3 analog keypad.

Description

AnalogKeypad is a simple library to read the keys from a (Robotdyn) 4x4 or 4x3 keypad. No other keypads are tested, but they should work with this library after adjusting the MAGIC NUMBERS in the function rawRead().

Interface

#include "AnalogKeypad.h"

Constructor

AnalogKeypad(const uint8_t pin, const uint8_t bits = 10) constructor, pin is typical A0 etc. Bits has a default of 10, but need to be set to match the platform. If bits < 8 then the internal shift would be large causing all reads to return 0 or so.

polling interface

uint8_t pressed() returns 0 if no key pressed, otherwise returns key pressed (may fluctuate).
uint8_t read() read the key pressed returns 0 .. 16 where 0 means NOKEY.

event interface

uint8_t event() checks if a change has occurred since last time.
uint8_t key() returns the key involved with last event.

  uint8_t e = AKP.event();
  switch (e)
  {
    case PRESSED:
      Serial.print("press\t");
      Serial.println(AKP.key());
      break;
    case RELEASED:
      Serial.print("release\t");
      Serial.println(AKP.key());
      break;
    case REPEATED:
      Serial.print("repeat\t");
      Serial.println(AKP.key());
      break;
    case CHANGED:
      Serial.print("change\t");
      Serial.println(AKP.key());
      break;
    default:  //  NOKEY
      break;
  }

Event	value
PRESSED	0x80
RELEASED	0x40
REPEATED	0x20
CHANGED	0x10
NOKEY	0x00

Operation

The simplest usage is to use the read() function. This will return a 0 (NOKEY) when no key is pressed and a number 1 to 16 for the keys pressed. Note the return value may fluctuate randomly when multiple keys are pressed.

The pressed() function is a bit more robust. It returns the key pressed first, so multiple key presses simultaneously are less likely to disturb your program.

See Examples

Future

Must

Should

more examples
- self-learning example?

Could

make internal mapping array runtime adaptable?
- store in RAM, accessor functions
version for external ADC
- see ADC712

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