Date of Award


Document Type



Santa Clara: Santa Clara University, 2014.


This report discusses the project of creating a manual charging phone case for smartphones by means of electromagnetic induction. In today's world, smartphones are being used on the go more often, creating an increased demand for battery life. The capacity of current batteries cannot keep up with the constant usage of data in such activities as emailing, social media, apps, and more. We developed an efficient, ergonomic, and aesthetically pleasing phone case that can manually charge a smartphone without an electrical outlet, but by means of electromagnetic induction. This product would target two main demographics: business people who are constantly on the go, and the outdoors enthusiasts who are not always near an electrical outlet. The product will give users peace of mind knowing that their phone will not die without an outlet or a plug-in phone charger. The phone case would feature a magnet and coil system as an electrical power generator. The magnet and coil will convert energy from mechanical input created by the user spinning a wheel mounted to the rear face of the case. The rotational input of the user is transferred to the generator via a gear train with a final drive ratio of 1:48. With an average input of 4 newtons of force, 2 revolutions per second, and a radius of 2 centimeters of the disc, the mechanical energy provided will create the needed voltage and current for approximately 1 Watt of electrical power. A smartphone draws around 0.4 to 0.5 Watts of power in an idle state, meaning that this 1 Watt will provide the power to overcome idle power draw. We made a simple and intuitive case that features lightweight, ergonomic, and efficient attributes. Physical testing has been conducted on selected generators, yielding promising results. Housing prototypes were 3D printed for fitment testing, while drop tests were conducted theoretically through FEA modelling and testing.