Editor’s Note: The MiniPOV v3 kit necessary to build this project has been discontinued
Best known for inventing TV-B-Gone, a keychain that turns off TVs in public places, Mitch Altman is interested in any technology that gives people more choices for improving their lives.
You don’t have to be a Buddhist monk to meditate, or a Sleeping Beauty to sleep well. Achieve these altered states of consciousness, and others, with this simple microcontroller device.
What would happen if you could play a recording of brain waves into someone’s brain? That question popped into my mind one day while I was meditating, and it turns out that there are devices that can do this. Sound and Light Machines (SLMs) produce sound and light pulses at brain wave frequencies, which help people sleep, wake up, meditate, or experience whatever state of consciousness the machine is programmed for. The first time I tried one was a trip! Not only did I follow the sequence into a deep meditation and then out again (feeling wonderful!), but along the way I had beautiful, outrageous hallucinations.
RIDE YOUR OWN BRAIN WAVES
This article shows you how to build an SLM for much cheaper than you can buy one. We’ll do it the easy way, by hacking a microcontroller project that already exists: Limor Fried’s MiniPOV kit. This cool toy blinks pictures and words in the space you wave it through, and we can transform it into an SLM simply by changing the firmware and some minor hardware.
HOW SOUND AND LIGHT HACK THE BRAIN</h4
The brain produces varying proportions of brain wave types, depending on its current levels of relaxation, focus, and other mental states. Each type of wave has its own characteristic frequency range, which can be read by electroencephalography. Many people’s brain waves will synchronize to lights and sounds pulsing at brain wave frequencies, and this makes the brain change its state — a process called “entrainment.” By playing sequences of pulses into your eyes and ears, you can program your brain to follow any brain wave experience you like.
Illustrations by Timmy Kucynda
HOME ENTRAINMENT SYSTEM
We’ll program our SLM to follow a 14-minute sequence that tracks the meditation experience. Since the device generates only one frequency at a time, it phases in new brain states by switching fre- quencies back and forth. For example, to go from fully awake to somewhat dreamy, we generate beta for a while, then alpha, then toggle between beta and alpha, reducing the duration of beta and increasing that of alpha with each iteration. Our code’s brainwave Tab array defines the full sequence.
- Brain entrains to the programmed wave sequence, and alters its state accordingly.
- Battery pack powers the electronics.
- LEDs in front of user’s (closed) eyes pulse light at 2. 2, 6.0, 11. 1, or 14.4Hz, in order to elicit delta, theta, alpha, or beta waves, respectively.
- Headphone speakers play different tones into right and left ears, to produce binaural beats (see below) that match the LED pulse frequencies.
- Microcontroller on circuit board runs the firmware, the program that resides in the microcontroller, which controls the LEDs and headphones.
- Serial port connector writes the firmware into the microcontroller, letting you program your own brain wave frequency sequences.
- Graphics simply look cool.
Instead of simply playing the entraining wave frequency through both headphone speakers, we employ a more effective method. When we play different frequencies into each ear, the brain perceives a binaural beat frequency just as if the two tones were played next to each other on guitar strings. The beat results from the two tones cyclically reinforcing and canceling each other out, at a rate that equals the difference between the frequencies.
To generate a beta binaural beat, we play a 400Hz tone in one ear and a 414.4Hz tone in the other. The user perceives a sound, sort of like “wah-oo-wah-oo-wah,” that fades in and out 14. 4 times per second.