diff --git a/libraries/PinInGroup/LICENSE b/libraries/PinInGroup/LICENSE
new file mode 100644
index 00000000..ed401f22
--- /dev/null
+++ b/libraries/PinInGroup/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2017-2020 Rob Tillaart
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/libraries/PinInGroup/PinInGroup.cpp b/libraries/PinInGroup/PinInGroup.cpp
index 460e4ffe..bd3c3afc 100644
--- a/libraries/PinInGroup/PinInGroup.cpp
+++ b/libraries/PinInGroup/PinInGroup.cpp
@@ -1,57 +1,59 @@
 //
 //    FILE: PinInGroup.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.0
+// VERSION: 0.1.1
 //    DATE: 2017-04-26
 // PURPOSE: PinInGroup library for Arduino
-//          goal is to easily change a group of pins that logically 
+//          goal is to easily read a group of pins that logically
 //          belong to each other.
 //          The pins can be in any order.
-//     URL: http://forum.arduino.cc/index.php?topic=469599.0
+//     URL: https://github.com/RobTillaart/PinInGroup
+//          http://forum.arduino.cc/index.php?topic=469599.0
 //
-// Released to the public domain
-//
-// 0.1.0 - initial version (based upon pinGroup)
-// 
+// 0.1.0   2017-08-20  initial version (based upon pinGroup)
+// 0.1.1   2020-05-19 refactor; added clear(); added param for INPUT or INPUT_PULLUP
 
 #include "PinInGroup.h"
 
 PinInGroup::PinInGroup()
+{
+  clear();
+}
+
+void PinInGroup::clear()
 {
   _size = 0;
 }
 
-bool PinInGroup::add(uint8_t size, int* ar)
+uint8_t PinInGroup::add(uint8_t sz, uint8_t * ar, uint8_t value)
 {
-  bool b = true;
-  for (uint8_t i = 0; i < size; i++) 
+  int n = 0;
+  for (uint8_t i = 0; i < sz; i++)
   {
-    b = b && add(ar[i]);
+    n += add(ar[i], value);
   }
-  return b;
+  return n;
 }
 
-bool PinInGroup::add(uint8_t pin)
+uint8_t PinInGroup::add(uint8_t pin, uint8_t value)
 {
-  if (_size < PININGROUP_MAXSIZE)
-  {
-    _pins[_size] = pin;
-    pinMode(pin, INPUT);
-    _size++;
-    return true;
-  }
-  return false;
+  if (_size >= PININGROUP_MAXSIZE) return 0;
+  _pins[_size] = pin;
+  pinMode(pin, value);
+  _size++;
+  return 1;
 }
 
 uint16_t PinInGroup::read()
 {
   uint16_t value = 0;
+  uint16_t mask = 0x01;
   for (uint8_t i = 0; i < _size; i++)
   {
-    value <<= 1;
-    value = value | (digitalRead(_pins[i]) > 0 ? 1: 0);
+    if (digitalRead(_pins[i])) value |= mask;
+	mask <<= 1;
   }
   return value;
 }
 
-// --- END OF FILE ---
\ No newline at end of file
+// --- END OF FILE ---
diff --git a/libraries/PinInGroup/PinInGroup.h b/libraries/PinInGroup/PinInGroup.h
index 2485a1d6..368ad13b 100644
--- a/libraries/PinInGroup/PinInGroup.h
+++ b/libraries/PinInGroup/PinInGroup.h
@@ -1,41 +1,55 @@
-#ifndef PININGROUP_H
+#pragma once
 //    FILE: PinInGroup.h
 //  AUTHOR: Rob dot Tillaart at gmail dot com
-// VERSION: 0.1.0
+// VERSION: 0.1.1
+//    DATE: 2017-04-26
 // PURPOSE: PinInGroup library for Arduino
 // HISTORY: See PinInGroup.cpp
 //
-// Released to the public domain
+// Note: ESP32 has some dedicated IO pins that cannot be used in a group.
+//       FLASH: pin 6 - 11  (maybe more)
 //
+
 #include "Arduino.h"
 
-#define PININGROUP_LIB_VERSION "0.1.0"
-#define PININGROUP_MAXSIZE      16
+#define PININGROUP_LIB_VERSION "0.1.1"
+
+// smaller MAXSIZE will reduce memory footprint with ditto bytes.
+#ifndef PININGROUP_MAXSIZE
+#define PININGROUP_MAXSIZE    16
+#endif
+
 
-//
-// a PinInGroup is a group of up to sixteen input pins that can be read 
-// by means of one read command and combined into one uint16_t.
-// 
 class PinInGroup
 {
-public:
-  PinInGroup();
-  
-  // adds a predefined array of pinnumbers to the PinInGroup
-  bool      add(uint8_t s, int* ar);
-  // adds a single pin to the PinInGroup
-  bool      add(uint8_t pin);
+  public:
+    PinInGroup();
 
-  // read up to 8 pins "simultaneously" into one byte.
-  uint16_t   read();
+    // enables one to reset the pinGroup and repopulate it
+    void      clear();
 
-  // get the current size of the PinInGroup.
-  uint8_t   size() { return _size; };
-  // check how many free slots there are...
-  uint8_t   free() { return PININGROUP_MAXSIZE - _size; };
-  
-private:
-  uint8_t   _pins[PININGROUP_MAXSIZE];    // should be malloced dynamically
-  uint8_t   _size = 0;
+    // adds a predefined array of pin numbers to the PinInGroup
+    // sets all to either INPUT or INPUT_PULLUP.
+    uint8_t    add(uint8_t sz, uint8_t * ar, uint8_t value = INPUT);
+
+    // adds a single pin to the PinInGroup
+    uint8_t    add(uint8_t pin, uint8_t value = INPUT);
+
+    // read up to 16 pins "simultaneously" in one call.
+    uint16_t  read();
+
+    uint8_t   size() {
+      return _size;
+    };
+
+    // check how many free "slots" there are...
+    uint8_t   free() {
+      return PININGROUP_MAXSIZE - _size;
+    };
+
+  private:
+    uint8_t   _pins[PININGROUP_MAXSIZE];
+    uint8_t   _size = 0;
 };
-#endif
+
+// -- END OF FILE --
diff --git a/libraries/PinInGroup/README.md b/libraries/PinInGroup/README.md
new file mode 100644
index 00000000..d9acc7e5
--- /dev/null
+++ b/libraries/PinInGroup/README.md
@@ -0,0 +1,37 @@
+# PinInGroup
+
+Arduino library to group reading to 16 input pins in one command
+
+# Description
+
+A PinInGroup holds a number of input pins that can be read by means of a single **read()** command.
+The PinInGroup makes it easier to work with a number of inputs that are a logical unit,
+e.g. think of reading a parallel bus or read 4 lines from a matrix keyboard, or just 
+read an array of switches.
+
+### Performace
+
+The PinInGroup is not much more efficient as reading the pins in a loopyourself.
+Hoewever it is less programming and gives clearer code.
+
+There exist some ideas to optimize the low level reading e.g. only reading
+the registers only once, or hold register and bit info per pin.
+These ideas will be explored when time permits. 
+
+Note: The current ideas are platform specific.
+
+### interface
+
+**clear()** sets the size to zero so one can repopulate.
+
+**add()** adds a predefined array of pins of a single pin to the group. 
+Note one can set a 2nd parameter mode to **INPUT**(default) or **INPUT_PULLUP**.
+
+**read(value)** reads a 16 bits unsigned int from max 16 pins.
+
+**size()** and **free()** give information about the group.
+
+# Operation
+
+See examples
+
diff --git a/libraries/PinInGroup/examples/testPinInGroup/testPinInGroup.ino b/libraries/PinInGroup/examples/testPinInGroup/testPinInGroup.ino
index c7870f1c..04079eb7 100644
--- a/libraries/PinInGroup/examples/testPinInGroup/testPinInGroup.ino
+++ b/libraries/PinInGroup/examples/testPinInGroup/testPinInGroup.ino
@@ -2,26 +2,34 @@
 //  AUTHOR: Rob dot Tillaart at gmail dot com
 // VERSION: 0.1.0
 // PURPOSE: demo PinInGroup library for Arduino
-// HISTORY: 20-08-2017 
+// HISTORY: 20-08-2017
 //
 // Released to the public domain
 //
 
 #include "PinInGroup.h"
 
-int ar[4] = {2, 3, 4, 13};
+uint8_t ar[4] = {2, 3, 4, 23};
+uint8_t alt[] = {23, 22, 1, 3, 21, 19, 18, 5, 23, 22, 1, 3, 21, 19, 18, 5};
 
 void setup()
 {
   Serial.begin(115200);
-  Serial.print("\nPININGROUP_LIB_VERSION: ");
+  Serial.println(__FILE__);
+
+  Serial.print(F("\nPININGROUP_LIB_VERSION: "));
   Serial.println(PININGROUP_LIB_VERSION);
+  Serial.println();
 
   test0();
   test1();
   test2();
- 
-  Serial.println("done...");
+  test3();
+  test4();
+  test5();
+  test6();
+
+  Serial.println(F("done..."));
 }
 
 void loop()
@@ -31,24 +39,38 @@ void loop()
 // TEST1 verifies and times basic working
 void test0()
 {
-  pinMode(2, INPUT);
+  Serial.println();
+  Serial.println(__FUNCTION__);
+  delay(20);
+
+  uint16_t n1 = 0;
+
   uint32_t t1 = micros();
-  digitalRead(2);
-  digitalRead(2);
-  digitalRead(2);
-  digitalRead(2);
+  n1 = digitalRead(2) > 0;
+  n1 <<= 1;
+  n1 |= digitalRead(3) > 0;
+  n1 <<= 1;
+  n1 |= digitalRead(4) > 0;
+  n1 <<= 1;
+  n1 |= digitalRead(13) > 0;
   uint32_t t2 = micros();
 
-  Serial.print("time: ");
+  Serial.print(F(" val: "));
+  Serial.println(n1, BIN);
+  Serial.print(F("time: "));
   Serial.println(t2 - t1);
-  Serial.println("Test0 done...");
+  Serial.print(F("time: "));
+  Serial.println((1.0 * (t2 - t1)) / 4, 1);
+  Serial.println(F("Test0 done..."));
   Serial.println();
 }
 
 void test1()
 {
+  Serial.println();
+  Serial.println(__FUNCTION__);
   uint16_t n1;
-  
+
   PinInGroup PIG;
   PIG.add(2);
   PIG.add(4);
@@ -59,41 +81,230 @@ void test1()
   Serial.println(PIG.size());
   Serial.print("free: ");
   Serial.println(PIG.free());
+  delay(20);
 
   uint32_t t1 = micros();
   n1 = PIG.read();
   uint32_t t2 = micros();
 
-  Serial.print(" val: ");
-  Serial.println(n1);
-  Serial.print("time: ");
+  Serial.print(F(" val: "));
+  Serial.println(n1, BIN);
+  Serial.print(F("time: "));
   Serial.println(t2 - t1);
-  Serial.println("Test1 done...");
+  Serial.print(F("time: "));
+  Serial.println((1.0 * (t2 - t1)) / PIG.size(), 1);
+  Serial.println(F("Test1 done..."));
   Serial.println();
 }
 
 void test2()
 {
-  uint16_t n1;
-  
-  PinInGroup PIG;
-  for (int p=2; p<14; p++) PIG.add(p);
+  Serial.println();
+  Serial.println(__FUNCTION__);
 
-  Serial.print("size: ");
+  uint16_t n1;
+
+  PinInGroup PIG;
+
+#if defined(ESP32) || defined(ESP8266)
+  // be carefull which pins you use for ESP32  (and probably 8266 too, not tested)
+  // note: GPIO06 through GPIO11 are reserved for the FLASH.
+  //       You cannot use them.  ==> pinMode() fails.
+  // https://github.com/espressif/arduino-esp32/issues/1411
+  //
+  for (uint8_t p = 20; p < 36; p++) PIG.add(p);
+#else
+  for (uint8_t p = 2; p < 14; p++) PIG.add(p);
+#endif
+
+  Serial.print(F("size: "));
   Serial.println(PIG.size());
-  Serial.print("free: ");
+  Serial.print(F("free: "));
   Serial.println(PIG.free());
+  delay(20);
 
   uint32_t t1 = micros();
   n1 = PIG.read();
   uint32_t t2 = micros();
 
-  Serial.print(" val: ");
-  Serial.println(n1);
-  Serial.print("time: ");
+  Serial.print(F(" val: "));
+  Serial.println(n1, BIN);
+  Serial.print(F("time: "));
   Serial.println(t2 - t1);
-  Serial.println("Test1 done...");
+  Serial.print(F("time: "));
+  Serial.println((1.0 * (t2 - t1)) / PIG.size(), 1);
+  Serial.println(F("Test2 done..."));
   Serial.println();
 }
 
-// END OF FILE
\ No newline at end of file
+void test3()
+{
+  Serial.println();
+  Serial.println(__FUNCTION__);
+
+  uint16_t n1;
+
+  PinInGroup PIG;
+  PIG.add(4, ar, INPUT_PULLUP);
+  PIG.add(4, ar, INPUT_PULLUP);
+  PIG.add(4, ar, INPUT_PULLUP);
+  PIG.add(4, ar, INPUT_PULLUP);
+
+  Serial.print(F("size: "));
+  Serial.println(PIG.size());
+  Serial.print(F("free: "));
+  Serial.println(PIG.free());
+
+  PIG.add(4, ar, INPUT_PULLUP);  // should not be added
+
+  Serial.print(F("size: "));
+  Serial.println(PIG.size());
+  Serial.print(F("free: "));
+  Serial.println(PIG.free());
+  Serial.println();
+  delay(20);
+  PIG.clear();
+
+  for (int i = 1; i <= 16; i++)
+  {
+    PIG.add(23);
+    uint32_t t1 = micros();
+    n1 = PIG.read();
+    uint32_t t2 = micros();
+    float timePerPin2 = (1.0 * t2 - t1) / i;
+
+    Serial.print(i);
+    Serial.print('\t');
+    Serial.print(t2 - t1);
+    Serial.print('\t');
+    Serial.print(timePerPin2);
+    Serial.print('\t');
+    Serial.println(n1, BIN);
+    delay(20);
+  }
+
+  Serial.println(F("Test3 done..."));
+  Serial.println();
+}
+
+void test4()
+{
+  Serial.println();
+  Serial.println(__FUNCTION__);
+
+  uint16_t n1;
+
+  PinInGroup PIG;
+  PIG.add(4, ar, INPUT_PULLUP);
+  PIG.add(4, ar, INPUT_PULLUP);
+  PIG.add(4, ar, INPUT_PULLUP);
+  PIG.add(4, ar, INPUT_PULLUP);
+
+  Serial.print(F("size: "));
+  Serial.println(PIG.size());
+  Serial.print(F("free: "));
+  Serial.println(PIG.free());
+
+  PIG.clear();
+  PIG.add(4, ar, INPUT_PULLUP);  // should not be added
+
+  Serial.print(F("size: "));
+  Serial.println(PIG.size());
+  Serial.print(F("free: "));
+  Serial.println(PIG.free());
+  delay(20);
+
+  uint32_t t1 = micros();
+  n1 = PIG.read();
+  uint32_t t2 = micros();
+
+  Serial.print(F(" val: "));
+  Serial.println(n1, BIN);
+  Serial.print(F("time: "));
+  Serial.println(t2 - t1);
+  Serial.print(F("time: "));
+  Serial.println((1.0 * (t2 - t1)) / PIG.size(), 1);
+  Serial.println(F("Test4 done..."));
+  Serial.println();
+}
+
+void test5()
+{
+  Serial.println();
+  Serial.println(__FUNCTION__);
+
+  uint16_t n1 = 0;
+
+  uint32_t t1 = micros();
+  n1 = digitalRead(2) > 0;
+  n1 <<= 1;
+  n1 |= digitalRead(3) > 0;
+  n1 <<= 1;
+  n1 |= digitalRead(4) > 0;
+  n1 <<= 1;
+  n1 |= digitalRead(13) > 0;
+  uint32_t t2 = micros();
+  float timePerPin = (1.0 * t2 - t1) / 4;
+
+  Serial.print(F(" val: "));
+  Serial.println(n1, BIN);
+  Serial.print(F("time: "));
+  Serial.println(t2 - t1);
+  Serial.print(F("time: "));
+  Serial.println(timePerPin);
+  Serial.println();
+
+  PinInGroup PIG;
+
+  for (int i = 1; i <= 16; i++)
+  {
+    PIG.add(2);
+    t1 = micros();
+    n1 = PIG.read();
+    t2 = micros();
+    float timePerPin2 = (1.0 * t2 - t1) / i;
+
+    Serial.print(i);
+    Serial.print('\t');
+    Serial.print(t2 - t1);
+    Serial.print('\t');
+    Serial.print(timePerPin2);
+    Serial.print('\t');
+    Serial.println(timePerPin2 / timePerPin * 100.0);
+    delay(20);
+  }
+
+
+  Serial.println(F("Test5 done..."));
+  Serial.println();
+}
+
+
+void test6()
+{
+  Serial.println();
+  Serial.println(__FUNCTION__);
+
+  uint16_t n1 = 0;
+
+  PinInGroup PIG;
+
+  // verify pin stays same place in output.
+  // connect selected pin to GND and it should stay on same spot.
+  // even when pins are added.
+  for (int i = 1; i <= 10; i++)
+  {
+    PIG.add(i, INPUT_PULLUP);
+    n1 = PIG.read() + 32768;
+
+    Serial.print(i);
+    Serial.print('\t');
+    Serial.print(n1, BIN);
+    Serial.print('\n');
+  }
+
+  Serial.println(F("Test6 done..."));
+  Serial.println();
+}
+
+// -- END OF FILE --
\ No newline at end of file
diff --git a/libraries/PinInGroup/library.json b/libraries/PinInGroup/library.json
index ecdc883b..fa96f2f7 100644
--- a/libraries/PinInGroup/library.json
+++ b/libraries/PinInGroup/library.json
@@ -1,6 +1,6 @@
 {
   "name": "PinInGroup",
-  "keywords": "PinInGroup,pin,group",
+  "keywords": "PinInGroup, pin, group, INPUT",
   "description": "A class that groups input pins so they can be read in one logical step",
   "authors":
   [
@@ -13,12 +13,12 @@
   "repository":
   {
     "type": "git",
-    "url": "https://github.com/RobTillaart/Arduino.git"
+    "url": "https://github.com/RobTillaart/PinInGroup.git"
   },
-  "version":"0.1.0",
+  "version":"0.1.1",
   "frameworks": "arduino",
   "platforms": "*",
   "export": {
-    "include": "libraries/PinInGroup
+    "include": "PinInGroup
   }
 }
diff --git a/libraries/PinInGroup/library.properties b/libraries/PinInGroup/library.properties
index 6af2de9c..93b325ce 100644
--- a/libraries/PinInGroup/library.properties
+++ b/libraries/PinInGroup/library.properties
@@ -1,9 +1,11 @@
-name=pinGroup
-version=0.1.0
+name=PinInGroup
+version=0.1.1
 author=Rob Tillaart <rob.tillaart@gmail.com>
 maintainer=Rob Tillaart <rob.tillaart@gmail.com>
 sentence=A class that groups input pins so they can be read in one logical step.
 paragraph= 
-category=Uncategorized
-url=https://github.com/RobTillaart/Arduino/tree/master/libraries
-architectures=*
\ No newline at end of file
+category=Communication
+url=https://github.com/RobTillaart/PinInGroup
+architectures=*
+includes=PinInGroup.h
+depends=