The ambition to create a device that facilitates quick and easy lucid dreaming entrance has led to the appearance of assorted technologies that claim to fulfill such a role. As already stated, none of these devices has been proven effective.
The most famous of these is the Hemi-Sync system, which purports to synchronize the two hemispheres of the brain. Hemi-Sync was developed by Robert Monroe, an American esotericism expert and researcher. The idea behind Hemi-Sync is that out-of-body sensations may be induced by achieving synchronization of the brain’s two hemispheres. However, this type of approach yields a paradox for the lack of scientific (or pseudo-scientific) evidence that hemispheric synchronization influences sensory perception. Actually, it is the cerebral cortex and constituents that are primarily responsible for sensory perception. At the beginning of the 20th century, it became clear that the key roles in sensory processes are played by varying levels of inhibition and activity in the cerebral cortex. Synchronization devices have no effect on the operation of the cerebral cortex.
The idea of using sounds of various frequencies to induce a specific level of electrical activity in the brain is, so far, considered impossible. Thus, the sounds and noises used to assist separation from the body cannot directly affect the process, but merely serve as cueing signals. Such a system works only after having been used for a long time, if it works at all. Moreover, it might only work once or twice. Usually, it never works at all. Nevertheless, synchronization systems are able to help practitioners reach a free floating state of consciousness since the systems prevent sleep or induce wakefulness, providing fertile ground for direct lucid dreaming entry.
The idea of inducing various lucid dreaming states through sound has gained wide attention. Many other programs and technologies have appeared as a result, including, for example, the Brain Wave Generator (BWG), which allows the practitioner to independently experiment with a wide array of sounds and frequencies and various methods of transmission. The effect is the same: cueing during sleep or the maintenance of a transitional state. Thus, there is no noticeable difference between using machines and listening to similar sounds or musical compositions.
Inasmuch as the devices described above have not delivered notable result, the search for new technologies continues unhindered. The number of ideas for exerting noninvasive influence over the brain and its constituent parts is increasing. For example, there is a theory that lucid dreaming experiences may be induced by electromagnetically stimulating the left angular gyrus. However, this, like all other non-autonomous methods, is strictly based on theory. At present, consistent, focused, and unassisted practice is the simplest and only guaranteed means to achieving lucid dreaming entrance.