In the case of miniaturized telemetry capsules, such as a capsule endoscope that can acquire and transmit images from the intestines, the size and the power consumption of the module are restricted. In the capsule endoscopes, it is desirable that the control function can capacitate the sampling of digestive fluid and tissue, drug delivery, and locomotion. In this paper, the control function was embodied by bi-directional communication. A CPLD (complex programmable logic device) controller was designed and implemented for the bi-directional communication in capsule endoscope. The diameter of capsule was 12 mm and the length was 30 mm. The performance of implemented capsule was verified by in-vivo animal experiments.

Diseases of the gastro-intestinal tract are becoming more prevalent. New techniques and devices, such as the wireless capsule endoscope and the telemetry capsule, that are able to measure the various signals of the digestive organs (temperature, pH, and pressure), have been developed for the observation of the digestive organs. In these capsule devices, there are no methods of moving and grasping them. In order to make a swift diagnosis and to give proper medication, it is necessary to control the moving speed of the capsule. This paper presents a wireless system for the control of movements of an electrical stimulus capsule. This includes an electrical stimulus capsule which can be swallowed and an external transmitting control system. A receiver, a receiving antenna (small multi-loop), a transmitter, and a transmitting antenna (monopole) were designed and fabricated taking into consideration the MPE, power consumption, system size, signal-to-noise ratio and the modulation method. The wireless system, which was designed and implemented for the control of movements of the electrical stimulus capsule, was verified by in-vitro experiments which were performed on the small intestines of a pig. As a result, we found that when the small intestines are contracted by electrical stimuli, the capsule can move to the opposite direction, which means that the capsule can go up or down in the small intestines.