Ellen Page was walking home through a shabbier strip of her Adams Morgan neighborhood one night last year when the 25-year-old decided to do what she often does if she feels unsafe: call someone to chat for the rest of the walk.

So she dialed her dad — in Memphis.

Her sense of security was mostly illusory. “We were talking about how this system isn’t really effective for keeping women safe and it’s what 90 percent of my friends do when they walk home late, whether it’s from a party or from work,” Page said.

“If something were to happen to me ... the person on the end of the phone wouldn’t know exactly where I was,” she added.

Page and her father, Jonathan, have since crafted a smartphone case that acts as a panic button. When activated, the case can belt an alarm at 110 decibels and send a map of your location, via text message, to an emergency contacts list.

Ellen Page, 25, designed the Coyote Case, which sends out an alarm in emergency situations. (Jeffrey MacMillan/JEFFREY MACMILLAN)

The Coyote Case — named for the wild canine that howls when threatened — won an Innovation Award at the International CES in Las Vegas earlier this year, and Page said initial shipments should begin this summer.

The company’s market includes those who are most susceptible to attacks, such as urban dwellers, especially women, as well as college students, runners and cyclists, frequent travelers and the elderly.

“We wanted to create something that you didn’t have to remember to carry. I know tons of people who carry pepper spray, but leave it at home or at work,” said Page, who is leaving her job at the World Bank next month to focus on the venture.

The case arrives on the market as wireless carriers and public safety departments are modernizing 911 technology so that dispatchers can receive text messages. The nation’s four major carriers — Verizon, Sprint, AT&T and T-Mobile — have pledged to make text-to-911 available by the first half of next year, according to the Federal Communications Commission.

To activate the alarm , a user firmly rotates a dial on the back of the case from off to on, then squeezes tabs on either side of the dial simultaneously. The device emits a beeping sound that’s slightly louder than a standard car alarm to attract the attention of passersby.

“If you’re a woman and you’re attacked, that’s what your supposed to do – draw attention to yourself,” Page said. “And that’s not our natural inclination usually.”

The button also uses Bluetooth technology to connect with a smartphone app that automatically generates and sends a map of your location to a predetermined list of emergency contacts, such as police, family and friends or neighbors.

It’s designed to be simple enough for emergency situations, but complicated enough that it won’t accidentally activate in your pocket, Page said.

“The way that your body truly reacts when someone tries to harm you is you clench up,” Page said. “We wanted to create an intuitive system where you trigger it without thinking about how to trigger it.”

The devices carry a suggested retail price of $129, but are available for pre-order for $99 on the company’s Web site, www.coyotecase.com. It’s currently available for the iPhone 4, 4S and 5, Page said, and will soon be available for the Samsung Galaxy S3 and S4.