Hello, Just downloaded the OpenCat zip file and changed to use the nybble header file. I compiled and received some errors. Not sure how to move forward (haven't even tested servos for calibration yet. I did update the IRremote library to 2.6.1 in the library manager. Here is my output: n file included from D:\programming\Robots\Nybble\OpenCat\WriteInstinct\WriteInstinct.ino:32:0: D:\programming\Robots\Nybble\OpenCat\WriteInstinct\OpenCat.h: In member function 'void Motion::loadDataFromI2cEeprom(unsigned int&)': D:\programming\Robots\Nybble\OpenCat\WriteInstinct\OpenCat.h:660:51: warning: ISO C++ says that these are ambiguous, even though the worst conversion for the first is better than the worst conversion for the second: Wire.requestFrom(DEVICE_ADDRESS, skillHeader); ^ In file included from D:\programming\Robots\Nybble\OpenCat\WriteInstinct\OpenCat.h:86:0, from D:\programming\Robots\Nybble\OpenCat\WriteInstinct\WriteInstinct.ino:32: C:\Users\brads\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.4\libraries\Wire\src/Wire.h:68:13: note: candidate 1: uint8_t TwoWire::requestFrom(int, int) uint8_t requestFrom(int, int); ^~~~~~~~~~~ C:\Users\brads\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.4\libraries\Wire\src/Wire.h:65:13: note: candidate 2: uint8_t TwoWire::requestFrom(uint8_t, uint8_t) uint8_t requestFrom(uint8_t, uint8_t); ^~~~~~~~~~~ In file included from D:\programming\Robots\Nybble\OpenCat\WriteInstinct\WriteInstinct.ino:32:0: D:\programming\Robots\Nybble\OpenCat\WriteInstinct\OpenCat.h: At global scope: D:\programming\Robots\Nybble\OpenCat\WriteInstinct\OpenCat.h:855:1: warning: narrowing conversion of '-9.0e+1' from 'double' to 'int8_t {aka signed char}' inside { } [-Wnarrowing] }; ^ D:\programming\Robots\Nybble\OpenCat\WriteInstinct\OpenCat.h:855:1: warning: narrowing conversion of '-4.5e+1' from 'double' to 'int8_t {aka signed char}' inside { } [-Wnarrowing] D:\programming\Robots\Nybble\OpenCat\WriteInstinct\OpenCat.h:855:1: warning: narrowing conversion of '-9.0e+1' from 'double' to 'int8_t {aka signed char}' inside { } [-Wnarrowing] D:\programming\Robots\Nybble\OpenCat\WriteInstinct\OpenCat.h:855:1: warning: narrowing conversion of '-4.5e+1' from 'double' to 'int8_t {aka signed char}' inside { } [-Wnarrowing] D:\programming\Robots\Nybble\OpenCat\WriteInstinct\OpenCat.h:855:1: warning: narrowing conversion of '9.0e+1' from 'double' to 'int8_t {aka signed char}' inside { } [-Wnarrowing] D:\programming\Robots\Nybble\OpenCat\WriteInstinct\OpenCat.h:855:1: warning: narrowing conversion of '-4.5e+1' from 'double' to 'int8_t {aka signed char}' inside { } [-Wnarrowing] D:\programming\Robots\Nybble\OpenCat\WriteInstinct\OpenCat.h:855:1: warning: narrowing conversion of '9.0e+1' from 'double' to 'int8_t {aka signed char}' inside { } [-Wnarrowing] D:\programming\Robots\Nybble\OpenCat\WriteInstinct\OpenCat.h:855:1: warning: narrowing conversion of '-4.5e+1' from 'double' to 'int8_t {aka signed char}' inside { } [-Wnarrowing] D:\programming\Robots\Nybble\OpenCat\WriteInstinct\OpenCat.h: In function 'int SoundLightSensorPattern(char*)': D:\programming\Robots\Nybble\OpenCat\WriteInstinct\OpenCat.h:1112:34: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] skillByName("rest", 1, 1, 1); ^ D:\programming\Robots\Nybble\OpenCat\WriteInstinct\WriteInstinct.ino: In function 'void setup()': D:\programming\Robots\Nybble\OpenCat\WriteInstinct\WriteInstinct.ino:148:34: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] motion.loadBySkillName("rest"); ^ D:\programming\Robots\Nybble\OpenCat\WriteInstinct\WriteInstinct.ino: In function 'void loop()': D:\programming\Robots\Nybble\OpenCat\WriteInstinct\WriteInstinct.ino:260:29: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] skillByName("rest"); ^ D:\programming\Robots\Nybble\OpenCat\WriteInstinct\WriteInstinct.ino:299:45: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] motion.loadBySkillName("calib"); ^ Sketch uses 25616 bytes (79%) of program storage space. Maximum is 32256 bytes. Global variables use 1570 bytes (76%) of dynamic memory, leaving 478 bytes for local variables. Maximum is 2048 bytes. Low memory available, stability problems may occur. Any help is appreciated! -Brad