Speech-to-text capability is now baked into all modern computers. But what if you didn’t have to dictate to your computer? What if you could type just by thinking?

Silicon Valley startup Sabi is emerging from stealth with that goal. The company is developing a brain wearable that decodes a person’s internal speech into words on a computer screen. CEO Rahul Chhabra says its first product, a brain-reading beanie, will be available by the end of the year. The company is also designing a baseball cap version.

The technology is known as a brain-computer interface, or BCI, a device that provides a direct communication pathway between the brain and an external device. While many companies such as Elon Musk’s Neuralink are developing surgically implanted BCIs for people with severe motor disabilities, Sabi’s device could allow anyone to become a cyborg.

It’s not exactly Musk’s vision of the future, which involves implanted brain chips to allow humans to merge with AI. But venture capitalist Vinod Khosla, who was an early investor in OpenAI, says a noninvasive, wearable device is the only path to getting lots of people to use BCI technology.

“The biggest and baddest application of BCI is if you can talk to your computer by thinking about it,” says Khosla, founder of Khosla Ventures, one of Sabi’s investors. “If you’re going to have a billion people use BCI for access to their computers every day, it can’t be invasive.”

Sabi’s brain-reading hat relies on EEG, or electroencephalography, which uses metal disks placed on the scalp to record the brain’s electrical activity. Decoding imagined speech from EEG is already possible, but it’s currently limited to small sets of words or commands rather than continuous, natural speech.

Sensors line the inside of the cap and read brain signals noninvasively.Photograph: Courtesy of Sabi

The drawback of a wearable system is that the sensors have to listen to the brain through a layer of skin and bone, which dampens neural signals. Surgically implanted devices pick up much stronger signals because they sit so close to neurons. Sabi thinks the way to boost accuracy with a wearable is by massively scaling up the number of sensors in its device. Most EEG devices have a dozen to a few hundred sensors. Sabi’s cap will have anywhere from 70,000 to 100,000 miniature sensors.

“Given that high-density sensing, it pinpoints exactly what and where neural activity is happening. We use that information to get much more reliable data to decode what a person is thinking,” Chhabra says.

The company is aiming for an initial typing speed of 30 or so words per minute. That’s slower than most people type, but he says the speed will improve as users spend more time with the cap.