diff -r daf26b083899 -r b43536c064f6 lib/keypad/Keypad.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/keypad/Keypad.cpp	Mon Jan 28 21:51:45 2019 +0100
@@ -0,0 +1,88 @@
+#include "mbed.h"
+#include "Keypad.h"
+
+
+Keypad::Keypad(uint8_t nRows, DigitalIn rows[],
+	       uint8_t nColumns, DigitalOut cols[],
+	       int debounce_ms):
+  _rows(),
+  _columns(),
+  _debounce(debounce_ms),
+  _started(false),
+  _nrows(nRows),
+  _ncols(nColumns)
+{
+  printf("Setup Keypad: %dx%d\r\n", nColumns, nRows);
+  for(uint8_t c=0; c<nColumns; c++) {
+    _columns.push_back(cols[c]);
+    _columns[c].write(0);
+  }
+
+  for(uint8_t r=0; r<nRows; r++) {
+    _rows.push_back(rows[r]);
+    _rows[r].mode(PullDown);
+  }
+  _keys = new uint8_t[_nrows*_ncols];
+}
+
+Keypad::~Keypad()
+{
+  delete _keys;
+}
+
+void Keypad::run()
+{
+  uint8_t col=0;
+  uint8_t row;
+
+  for (row=0; row<(_ncols*_nrows); row++)
+    _keys[row] = 0;
+  while(_started) {
+    _columns[col].write(1);
+    Thread::wait(5);
+    for(row=0; row<_nrows; row++)
+      {
+	if (_rows[row].read())
+	  {
+	    if (_keys[row + _nrows*col] < 2)
+	      {
+		_keys[row + _nrows*col]++;
+		if ((_keys[row + _nrows*col] == 2) && _kp_callback)
+		  _kp_callback.call(row, col);
+	      }
+	  }
+	else
+	  {
+	    if (_keys[row + _nrows*col] > 0)
+	      {
+		_keys[row + _nrows*col]--;
+		if ((_keys[row + _nrows*col] == 0) && _kr_callback)
+		  _kr_callback.call(row, col);
+	      }
+	  }
+      }
+    _columns[col].write(0);
+    col = (col+1) % _ncols;
+    Thread::wait(5);
+  }
+}
+
+void Keypad::attach(const keyevent_callback_t& kp_callback,
+		      const keyevent_callback_t& kr_callback)
+{
+  _kp_callback = kp_callback;
+  _kr_callback = kr_callback;
+}
+
+void Keypad::start(void)
+{
+if (_started)
+  return;
+_started = true;
+_loop.start(this, &Keypad::run);
+}
+
+void Keypad::stop(void)
+{
+  _started = false;
+}