TL;DR
[Hemant] created an off-grid optical character recognition (OCR) server using an iPhone 8 powered entirely by solar energy. Typically, you'd expect an OCR server to require robust hardware, but the combination of this older smartphone and Apple’s Vision framework, which leverages machine learning for tasks like character recognition, makes it feasible. The iPhone’s battery serves as the initial power source, supplemented by a power bank to optimize its connection with a solar panel.