diff --git a/src/user_type.h b/src/user_type.h
new file mode 100644
index 00000000..06d20c96
--- /dev/null
+++ b/src/user_type.h
@@ -0,0 +1,132 @@
+///\file
+
+/******************************************************************************
+The MIT License(MIT)
+
+Embedded Template Library.
+https://github.com/ETLCPP/etl
+http://www.etlcpp.com
+
+Copyright(c) 2017 jwellbelove
+
+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.
+******************************************************************************/
+
+#ifndef __ETL_USER_TYPE__
+#define __ETL_USER_TYPE__
+
+///\defgroup user_type user_type
+/// Smart enumerations.<br>
+/// A method of declaring a user type that also contains a set of constants,
+/// but are not constrained to just those values.
+/// This contrasts with 'enum_type', where the values are expected to <b>only</b> contain
+/// those defined as constants.
+/// <b>Declaring the enumeration.</b>
+///\code
+///   DECLARE_USER_TYPE(CompassDirection, int)
+///   USER_TYPE(North, 0)
+///   USER_TYPE(South, 180)
+///   USER_TYPE(East,  90)
+///   USER_TYPE(West,  270)
+///   END_USER_TYPE
+///\endcode
+/// <b>Using the enumeration.</b>
+///\code
+/// CompassDirection direction;          // Default construction.
+///
+/// direction = CompassDirection::North; // Assignment from an enumeration constant;
+///
+/// int value = int(direction);          // Explicit conversion to 'int'.
+/// int value = direction.get();
+///
+/// const int& value = direction.get();  // Bind to internal value.
+///
+/// direction = CompassDirection(value); // Explicit conversion from 'int'.
+///
+/// direction = CompassDirection(3);     // Explicit conversion from a value.
+///
+/// ++direction;                         // Manipulate the value;
+/// direction -= 20;
+///
+/// direction = value;                   // Implicit conversion from 'int'. **** Compilation error ****
+///
+/// std::cout << "Direction = " << direction.c_str(); // Prints "Direction = North"
+///\endcode
+/// If a conversion to a string is not required then the 'ENUM_TYPE' declaration may be omitted.
+/// In that case the c_str() function will return a "?". This will also be the case for any
+/// enumeration value that does not have an ENUM_TYPE entry.
+///\ingroup utilities
+
+//*****************************************************************************
+// The declaration of the structure.
+//*****************************************************************************
+#define DECLARE_USER_TYPE(TypeName, ValueType) \
+  struct TypeName \
+  { \
+    enum enum_type \
+    { \
+
+//*****************************************************************************
+// The predefined constants.
+//*****************************************************************************
+#define USER_TYPE(enum_name, value) \
+      enum_name = value,
+
+//*****************************************************************************
+// The final section of the structure.
+//*****************************************************************************
+#define END_USER_TYPE \
+    }; \
+
+  typedef ValueType value_type; \
+  TypeName() {} \
+  TypeName(const TypeName &other) : value(other.value) {} \
+  TypeName(enum_type value) : value(value) {} \
+  TypeName& operator=(const TypeName &other) {value = other.value; return *this;} \
+  explicit TypeName(value_type value) : value(static_cast<enum_type>(value)) {} \
+  explicit operator value_type() const {return static_cast<value_type>(value);} \
+  value_type& get() {return static_cast<value_type>(value);} \
+  const value_type& get() const {return static_cast<value_type>(value);} \
+  TypeName& operator ++() { ++value; return *this; } \
+  TypeName operator ++(int) { TypeName temp(*this); TypeName::operator ++(); return temp; } \
+  TypeName& operator --() { --value; return *this; }
+  TypeName operator --(int) { TypeName temp(*this); TypeName::operator --(); return temp; } \
+  TypeName& operator +=(value_type rhs) { value += rhs; return *this; } \
+  TypeName& operator +=(const TypeName& rhs) { value += rhs.value; return *this; } \
+  TypeName& operator -=(value_type rhs) { value -= rhs; return *this; } \
+  TypeName& operator -=(const TypeName& rhs) { value -= rhs.value; return *this; } \
+  TypeName& operator *=(value_type rhs) { value *= rhs; return *this; } \
+  TypeName& operator *=(const TypeName& rhs) { value *= rhs.value; return *this; } \
+  TypeName& operator /=(value_type rhs) { value /= rhs; return *this; } \
+  TypeName& operator /=(const TypeName& rhs) { value /= rhs.value; return *this; } \
+  TypeName& operator %=(value_type rhs) { value %= rhs; return *this; } \
+  TypeName& operator %=(const TypeName& rhs) { value %= rhs.value; return *this; } \
+  TypeName& operator &=(value_type rhs) { value &= rhs; return *this; } \
+  TypeName& operator &=(const TypeName& rhs) { value &= rhs.value; return *this; } \
+  TypeName& operator |=(value_type rhs) { value |= rhs; return *this; } \
+  TypeName& operator |=(const TypeName& rhs) { value |= rhs.value; return *this; } \
+  TypeName& operator ^=(value_type rhs) { value ^= rhs; return *this; } \
+  TypeName& operator ^=(const TypeName& rhs) { value ^= rhs.value; return *this; } \
+  TypeName& operator <<=(value_type rhs) { value <<= rhs; return *this; } \
+  TypeName& operator >>=(value_type rhs) { value >>= rhs; return *this; } \
+private: \
+  value_type value; \
+};
+
+#endif