This weekend, guests at England’s Thorpe Park will face new fears.

The theme park will open its highly anticipated The Walking Dead roller coaster, featuring actors that jump out to scare guests on the already terrifying ride. However, there's one nightmare guests won’t have to face: a dead cellphone.

Brave passengers on The Walking Dead ride will spot a small box with red LED lights attached to their carriages. As their screams grow louder, the lights on the box will grow, too. The box is an energy harvester, which collects power from screams and vibrations and uses it to charge smartphones.

Scientists from Queen Mary University of London developed, designed, and installed the technology over the course of three months.

“The system uses a mini energy harvester to capture the kinetic energy, transferring it to a separate electrical circuit and storage unit, which is enough to charge a mobile phone,” Dr. Joe Briscoe from the school of engineering and materials science at Queen Mary University of London explained.

Staff at the theme park remove the storage units from the roller coaster after rides and install them at an on-site mobile charging point. Guests who are waiting for the ride will be able to charge their phones using power from previous riders’ screams.

The technology will be onboard the ride for a trial period. If successful, it may remain as a permanent addition.

The Walking Dead: The Ride will open to the public on April 1.