HatTip to Jay who is working on a tDCS/lucid dreaming project of his own.
tACS is transcranial alternating current, significantly more complex, from what I gather than tDCS. But perhaps a DIY tACS device set to 40 Hz specifically won’t be out of the question for DIYers. As someone who spent months (unsuccessfully) doing lucid dreaming exercises I certainly would welcome the opportunity to experience lucid dreaming.
The new dream study (paywall), which was published May 11 in Nature Neuroscience, used a far less invasive method: electrodes temporarily placed at strategic locations on the scalp. The research involved 24 volunteers with no history of lucid dreaming. The subjects went to sleep and eventually dreamed. Then, researchers turned on a 30-second-long electrical signal and then woke them up and asked them about their experiences. It turned out that a 40 Hz stimulation induced lucid dreams 77 percent of the time.
You can’t objectively measure a dream, though. So how did researchers know that the subjects weren’t just making it up? For one, the electrical stimulation was gentle enough that people couldn’t feel it, and some people were in a control group that had electrodes that never got turned on. Also, the study was double-blind: neither the volunteers nor the people who interviewed them were told who had what kind of stimulation. So it does seem that the effects were real.