The bat­tery on your mobile phone is dead, but you don’t have time to charge it in your room. You’re run­ning late and you have to catch the train. What do you do?

Begin­ning next Friday, swing by one of 30 campus loca­tions and pick up the Oomf, a free portable smart­phone charger. Just choose a cord that fits your phone, sign in to the Oomf app with your Face­book account or North­eastern email address, and then acti­vate the device using the four-​​letter code on the back.

Enter your credit card number as col­lat­eral and then get to where you need to be, knowing that you’ll be able to text, tweet, and place calls to your heart’s con­tent. Return the device to the so-​​called “Pow­er­Sta­tion” where you picked it up within 24 hours and it’s free, or pay a $5 per day fee until you give it back.

Portable power isn’t a con­ve­nience,” said North­eastern alumnus and Oomf co-​​founder James Riel, DMSB’13. “It’s a neces­sity to stay pro­duc­tive in today’s society.”

According to Riel, 300 Oomf’s will be avail­able to the North­eastern com­mu­nity. They will be dis­trib­uted to 30 campus loca­tions in 12 dif­ferent build­ings, including Snell Library, Shillman Hall, and the Curry Stu­dent Center. Some build­ings, including the Stetson East dining hall, will keep stacks of the devices in more than one location.

The trial pro­gram will run for sev­eral months, until stu­dents, fac­ulty, and staff have col­lec­tively used the Oomf 50,000 times. The devices will be hooked up to Northeastern’s Wi-​​Fi net­work, allowing Riel to track usage. “We’ll be able to see how many are being used, for how long they’re being used, and where they’re being used,” he explained.

The Oomf is cur­rently avail­able at more than two dozen Boston busi­nesses, from Game On to the Bradley & Diegel Salon. When you rent an Oomf from one of these estab­lish­ments, you must either pay $1 or watch an inter­ac­tive adver­tise­ment. Even­tu­ally the ads will be tai­lored to appeal to the spe­cific user, with a par­tic­ular focus on inter­ests and demographics.

We tell brands that we have a unique way of engaging with the mil­len­nial market, which has a great affinity for tech­nology,” Riel explained. “Instead of paying a fee, they can engage with a fun and inter­ac­tive ad in exchange for smart­phone power.”

Riel has already received $625,000 from angel investors and is looking to expand Oomf to Philadel­phia and New York City. He’s also part­nered with Best Bud­dies of Mass­a­chu­setts, becoming the offi­cial sponsor of its 2016 Boston Marathon charity team. As part of Oomf’s incip­ient Charge for Charity pro­gram, users have the option to pay the startup the typ­ical $1 fee or donate the money to the state’s Best Bud­dies pro­gram, an adver­tise­ment for which is played when you rent the device from select locations.

A lot of star­tups think that they can’t be char­i­table because of their lim­ited resources,” Riel explained, “but it’s impor­tant to us that we’re able to give back at such an early stage of development.”

None of this would have been pos­sible, he said, if not for Northeastern’s thriving entre­pre­neurial ecosystem. He cred­ited his entre­pre­neur­ship classes, the entre­pre­neurial spirit of his peers, and the men­tor­ship of entrepreneur-​​in-​​residence Bob Lentz for helping him build his busi­ness from the ground up. Lentz has been a par­tic­u­larly invalu­able resource, he said, helping him design his busi­ness pitch, build strategic part­ner­ships, and develop a cash flow analysis.

I don’t think I could have done any of this without North­eastern,” Riel said. “I was always around people with great ideas and was able to look to my pro­fes­sors to get insight from con­cep­tion to production.”