A cap that records your dreams

Brain-Computer Interfaces

You’ve chosen to imagine a cap that records your dreams while you sleep. You might want to learn more about brain-computer interfaces, which read signals made by our brains—although today’s technology cannot record dreams like movies. But when the Dream Cap does exist, don’t forget to erase the embarrassing dreams after you wake up!

Fun Facts:

In 1924, Hans Berger made the first recording of electrical signals from a human brain.
In 2013, Japanese researchers used brain scans to identify some kinds of images people saw while sleeping.
In 2021, sleeping people in lucid dreams answered simple questions from researchers using eye movements and facial signals.

Brain-Computer Interfaces

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We’re exploring brain-computer interfaces, tools that connect brains with computers. Our brains make tiny electrical signals as we think and sleep, and special sensors can measure some of these signals from outside our heads. Scientists already use these sensors to study sleep and brain activity. Researchers have even found clues about images people see while sleeping, though current devices cannot record or replay dreams like movies. If a future Dream Cap could reveal more about dreams, we would need rules about sharing them. So don’t forget to erase the embarrassing dreams from your Dream Cap after you wake up!

Fun Facts:

German scientist Hans Berger recorded the first human EEG in 1924. An EEG measures electrical activity from the brain.
UCLA researcher Jacques Vidal introduced the term “brain-computer interface” in
In 2013, researchers in Japan used brain scans and computers to identify types of images people saw during sleep. They could not record a dream like a movie.
In a 2021 experiment, lucid dreamers answered math and yes-or-no questions while still asleep. Some replied by moving their eyes in special patterns.
Researchers now use wearable EEG headbands to study sleep outside traditional sleep labs. These devices can track brain signals, although they cannot simply replay our dreams.

Discussion Question:

If a machine could someday record our dreams, who should be allowed to see them?

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Physical Build:

Make your own Dream Cap prototype using a paper strip, cardboard, foil, yarn, and tape. Add pretend brain sensors around the cap, then draw a “dream screen” showing what you imagine they might detect. Decide which parts of your dream machine should stay private and which could be shared.

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Digital Build:

With an adult, ask ChatGPT:

“Invent three very different dreams a future Dream Cap might discover.”

Choose one dream and draw what the cap might record. Then design a privacy button that lets you decide whether to save, erase, or share it.

or a bone conduction headband that sings you lullabies to sleep?

Lullaby Headband

Bone Conduction Audio

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You’ve chosen to imagine a headband that gently plays lullabies as you fall asleep. You might want to learn more about bone conduction audio, which sends sound vibrations through the skull. Just make sure your headband knows bedtime is not drum-solo time!

Fun Facts:

More than 400 years ago, people discovered that vibrations could carry sound through the teeth and skull.
Some children today wear bone conduction hearing devices on headbands to help them hear.
Bone conduction headphones can even play music while swimming because sound reaches the inner ear through vibrations.

Bone Conduction Audio

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We’ve decided to learn more about bone conduction audio, a different way for us to hear. Normal sounds usually travel through the air into our ears. Bone conduction sends tiny vibrations through bones in our skull instead. Those vibrations can reach the inner ear without blocking our ear canals. People already use this idea in hearing devices and special headphones. Future sleep headbands could use it to play gentle bedtime sounds. Designers would need to keep those sounds safe and comfortable for us. Just make sure your headband knows bedtime is not drum-solo time!

Fun Facts:

In the 1500s, Girolamo Cardano described hearing sound through a rod held between the teeth. The vibrations traveled through the skull.
In 1879, Richard S. Rhodes invented the Audiphone, an early bone conduction hearing aid. It was shaped like a fan and worn against your front teeth.
Beethoven may have used a wooden stick connected to his piano to feel its vibrations as his hearing worsened. Researchers say evidence for exactly how he used it is limited.
Bone conduction hearing aids today can be worn on a headband. They send vibrations through the skull toward the inner ear.
Shokz makes waterproof bone conduction headphones for swimmers. Because they use vibrations, swimmers can listen while leaving their ear canals open.

Discussion Question:

If a headband could play sounds without covering your ears, when might hearing the sounds around you still be important?

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Physical Build:

Make a Lullaby Headband model from a strip of cardboard, fabric scraps, tape, and two bottle caps. Place the caps near the sides of your head as pretend vibration pads. Draw controls for volume, music, and a timer, then invent a safety feature that keeps the sounds gentle.

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Digital Build:

With an adult, ask ChatGPT:

“Design a bedtime headband that uses gentle vibrations to play a peaceful lullaby.”

Use the description to draw your invention. Then add your own controls for sound, comfort, bedtime timing, and a quiet morning alarm.