Yes, you need LibSensel.dll. If you execute the installer that you find here:
https://github.com/sensel/sensel-api/blob/master/sensel-install/SenselLibWin0.8.2.exe
it will create a c:\Program Files\Sensel\SenselLib directory with the things you need to develop and execute custom programs in C. The appropriate LibSensel.dll file (32-bit or 64-bit) needs to either be copied from there into the same directory as morphosc.exe, or (I think, I haven’t tested this) the directory containing it can be added to the PATH value.
…Tim…
