Development platform for intelligent implants in real-time monitoring applications

Introduction Signal acquisition and processing are the essential tasks of intelligent implants and prostheses. For this purpose a modular hardware platform was developed. The implantable part realizes the detection, conversion and preprocessing of invasive recorded biological signals. It furthermore ensures data compression and transmission to the extracorporeal base station where post processing and the control of peripheral devices, e.g. robotic hand prosthesis, is performed. Methods The implant includes three main components: A bioamplifier (ADS1298R) a microcontroller (MSP430F6638), and a radio chip (ZL70102). The bioamplifier records signals with a sampling frequency from 250sps to 32ksps with 24bit resolution for each of the eight channels. The microcontroller provides the data processing, system control and communication protocol with the base station. The radio chip communicates within the allocated band of 402MHz to 405MHz and contains an on-chip 2,45GHz wake-up receiver. This device is designed to operate conform to the MICS standard. The base station comes with a DSP (TMS320C5535), a microcontroller (MSP430F6638), and the corresponding radio chip. Results The system forms an experimental platform to develop and evaluate hard- and software solutions for intelligent im-plants with the special focus on real-time, high data rate RF-transmission, which corresponds to the MICS standard. As an important feature the microcontroller performs and controls an automated RF-antenna tuning. This is essential to compensate biological and technical environmental influences and thus to enable a reliable transmission between intra- and extracorporeal devices in daily routine. Conclusion The presented platform offers a flexible modular hardware realization as a powerful development tool for intelligent implants with the focus on neuroprosthetic applications where a real-time transmission with high data rates is required. Further developments will focus the improvement of the wireless power supply, the reliability of the RF-transmission, as well as the efficiency of different encapsulation concepts.