Signal from C++ in QML

You are instantiation 2 separate Interface objects: one in C++, and another in QML. No wonder it does not work. Get a pointer to your QML instance using QObject::findChildren() (just remember that findChildren requires your QML object to be named in “objectName” property for the method to work) or use a timer in QML and trigger it from there. There are a few other ways to do it, but I won’t flood you with information right now.