(OPINION) One day phones will become devices integrated into our skin, rather than the black rectangular slabs we’ve become accustomed to, according to the inventor of the cell phone.

“The next generation will have the phone embedded under the skin of their ears,” Marty Cooper, who’s credited with inventing the first phone in 1973, told CNBC in an interview at the Mobile World Congress in Barcelona on Monday.

Such devices won’t need to be charged, as “your body is the perfect charger,” Cooper said. “When you eat food, your body creates energy, right?”

“You ingest food, your body creates energy. It takes a tiny bit of energy to run this earpiece,” he added. His vision hints at a possible future stage of humanity where our bodies are augmented with powerful microchips and sensors.

Several startups are developing technologies that seek to combine computers with the human brain, for example, such as Elon Musk’s Neuralink.

Cooper said the smartphone today has gotten too complex with numerous applications and a screen that doesn’t suit the curvature of the human face.

“Whenever I make a phone call and don’t have an earpiece, I have to take this flat piece of material against my curved head [and] hold my arm up in an awkward position,” he said.

The smartphone market has stagnated over the last few years, and there’s a feeling in the industry that manufacturers are struggling to come up with new innovative designs. The prevalence of phones today has resulted in a litany of problems, from social media addiction to privacy infringements.

“Privacy is a very serious problem, addiction is a problem,” Cooper said, acknowledging the ills of his creation. But he struck an optimistic tone for the future, suggesting the technology’s best days may still be ahead of it in fields like education and health care.

“I have an abiding faith in humanity,” Cooper said. “I look at history and look at all of the advances that we’ve had with technology, and somehow people have figured it out.”

“People are better off now. And they live longer. They are wealthier, they are healthier than they’ve ever been before. We have ups and downs. But in general, humanity is progressing.”