A new omnidirectional wireless power transmission solution for the wireless Endoscopic Micro-Ball

The wireless endoscopic Micro-Ball is used to capture images of gastrointestinal (GI) tracts and save them into Flash memories. The batteries will be exhausted after the Micro-Ball is excreted from human body. So a new wireless power transmission (WPT) solution is proposed to deliver energy from an image reader to the Micro-Ball to fetch the stored images. In this solution, considering that the posture of the Micro-Ball is uncertain when it is placed into the image reader and the volume of the Micro-Ball is too small to contain multiple receiving coils, we employ multiple emitting coils in the image reader and one single receiving coil inside the Micro-Ball. Additionally, an adaptive control mechanism is proposed to select the optimum emitting coil with the highest power efficiency to transmit wireless power to the Micro-Ball placed inside the image reader. As a result, the Micro-Ball can work well in the image reader under all postures with highest power efficiency. The experimental results prove that the power delivering efficiency is in the range of 32% to 36%.