Implementation of a joint power delivering and communication technology for smartphones over the 3.5 mm audio jack

Smartphones are quite popular nowadays, various smartphone centric applications have emerged, which use a smartphone in conjunction with microcontrollers and sensors for data acquisition, processing, display, communication, and storage. Many applications use the 3.5 mm audio interface in a smartphone for data communications so that they can work with diverse types of smartphones, but the problem on providing stable and sufficient power with data simultaneously from the 3.5 mm audio interface is unsolved. In this research, we have combined the frequency shift keying (FSK) modulation scheme with AudioTrack streaming mode in an app and established joint data and power transmission on both left and right audio channels of a smartphone. As a result, the smartphone can provide up to 36.3 mW power and 1.6 kbps data rate to a sensing platform. Furthermore, we have implemented a digital data filter, a power detector, a timing-error detector/corrector, and a differential Manchester decoder in the same app and achieved up to 7.35 kbps data rate from the sensing platform to the smartphone. Therefore, a novel and advanced method to transfer data and power from a smartphone’s 3.5 mm audio interface to a sensing platform is established. At the same time, receiving data from the sensing platform is maintained