Designing a smartphone torch app that allows users to select different colors for the light is feasible only if the smartphone is equipped with LEDs capable of emitting multiple colors. Most smartphones currently use a single white LED for the flashlight, which limits the app's functionality to displaying white light only. While it is technically possible to add additional LEDs (such as red, green, blue, and yellow) to enable color selection, this would require hardware modifications beyond just software development. Creating a multicolor torch app would be straightforward if the necessary hardware is in place, but the integration of such features into smartphones would need a compelling business case for manufacturers. Alternatives like using an IR LED transmitter for low-light visibility or external color filters could offer practical solutions without requiring significant hardware changes. Bi-color and tri-color LEDs do exist, which can be utilized for more advanced lighting applications, but they are not standard in most smartphones.
