Center for Wireless Integrated MicroSystems (WIMS) Neural Prosthesis Testbed Code Development for Neural Prosthesis and Environmental Monitoring Testbeds David A. Ortiz M.S. Student in Electrical Engineering Luis Calderon, Giselle Bonilla, Wilmarie Rios, Agnes Velez, Axel Claudio, José Ortiz, Debbie Ruperto, Lizbeth Matos, Abigail Fuentes, Angel Rios, Jomayra Marrero, Sahray Gambaro, Michael Ortiz, Feliut Guzman, Esteban Valentin, Guillermo Martinez Undergraduate Students Nayda G. Santiago Advisor Electrical and Computer Engineering Department University of Puerto Rico, Mayagüez Campus MCU Features Given the current status of WIMS board, emulation into the 8051 allows the design, implementation and testing of software update codes and LabVIEW Interfaces. The two microcontroller’s are low power consuming, and have most of the peripherals needed to send and receive data. The 8051 made by SiLabs has more memory that the WIMS MCU, enough to allow the emulation of some of the missing components that are part WIMS board. Tone Demo Description A simple tone sequence is sent to the MCU from a LabVIEW interface. The amplitude and frequency of the sound is sent and the MCU uses such data to generate the command word, needed by the hybrid chip simulation in order to activate the electrode stimuli. This is implemented at the output of the MCU where another LabVIEW interface will represent the electrode stimuli in a LED Array Interface. Environmental Monitoring Testbed Micro Gas Chromatograph Fig. 7 Environmental Monitoring Testbed A gas chromatograph is an instrument used to separate volatiles components of a mixture. Features of the Micro Gas Chromatograph: About 1-2 cm³ compared to the 2-3 feet of the normal GC MEMS (Micro Electro-Mechanical System) micro-sensors Fast analysis Ultra-low power consumption Hardware Implementation The goal is to build the hardware pertaining to the control of the complete micro gas chromatograph system. While MI is working on the gas chromatograph itself, our task is to set the controlling algorithms though the microcontroller of the system. This semester we are focused on simulating those parts of the system which are not available to us, so the creation and implementation of controlling algorithms can be done in parallel. The data received from the GC through the analog to digital converter will be generated by a signal generator. The pumps, valves, heaters and other devices whose time based functions will be controlled by the microcontroller will be simulated by an array of multicolored LEDs. Although at this point in the project the microcontroller will not be processing data, we will nonetheless use a LabVIEW interface on a host computer to display the data from the microGC. The input is provided by a simulation of a piano keyboard, it consists of the common keys and two buttons that play a predefine sequence of key strikes. The MCU must do the same error checking schemes used the WIMS board to prevent the data to be lost after being received and after sending it as output. All communication is done using a Data Acquisition boards. These that allow communication of LabVIEW interfaces with the outside world. Fig. 8. Hardware Description Fig.10 Microgas Chromatograph Data Processing Flow Chart Cochlear Implants Deafness affects between 9 and 22 of every 1000 people in the United States. Cochlear implant technology has emerged as an alternative for non-hearing patients. As time goes on cochlear implant, technology has been improved. The Center for Wireless Integrated Microsystems (WIMS) is developing a neural prosthesis for the human cochlea. New algorithms are implemented, to improve real time operation and low power consumption. The software to be implemented on the hardware designed by the WIMS group is still under development. As an alternative to test and debug the logic of the software, an 8051 MCU is being used. The data analysis consists of the following processes: signal smoothing, baseline, peak detection and area calculation. The signal received from the micro gas chromatograph contains certain amount of noise not allowing the correct identification of the type and concentration of a gas in the environment being monitored. The smoothing process filters the signal allowing us to reduce the amount of noise and be able to receive reliable data. The baseline and peak detection are used for the area calculation. The peak detection process identify the maximum points of the signal. These peaks provides us the type of gases present in a gas mixture. The baseline calculation is used as reference axis to determine the area under the peaks detected. The result of the area calculation of a peak represents the concentration of a certain gas. This research is supported by NSF (Award number: ). Acknowledgment Fig. 9 EMT Demo Block Diagram Data Analysis Current Work Our work is concerned with the simulation of the micro gas chromatograph and the development of Data Analysis algorithms. Recently, we worked on allocating peripheral devices to the ATMEL AT91R40008 Microcontroller. Some of the peripheral devices that we will be using to assemble the micro gas chromatograph prototype are the following: valves and pump, heaters, Zigbee Radio, among others. Existing code based on previous work and algorithms for the Data Analysis are under research. Our goal is to adapt and optimize existing code for the microcontroller AT91R Fig1. Cochlear Implant Fig Microcontroller Fig.3 WIMS Gen2 Microcontroller Fig.4 Piano Interface DSP Demo Description Fig.5 Continuous Interleaved Sampling Algorithm WIMS microcontroller has an internal custom made DSP, designed by Eric Marsman, Ph.D. student at UMich. The CIS Algorithm is hardcoded so that the DSP requires to be initialized before starting to process the data received from the ADC. Once initialized, the MCU goes to sleep mode until another process wakes it up. The purpose of the 8051 emulation is to understand the DSP’s behavior and to test the LabVIEW interfaces that communicate with it. Once initialized, the MCU goes to sleep mode until another process wakes it up. The purpose of the 8051 emulation is to understand the DSP’s behavior and to test the LabVIEW interfaces that communicate with it. The main goal is to create working code that generates the desired output, depending for which demo is being implemented for. There are two demos for the Neural Prosthesis Testbed: Tone Demo and DSP Demo. Integrated System Fig.6 Full System Block Diagram Two LabVIEW interfaces are going to be implemented in such a way a communication between two computers is done. A last inspection is done to confirm information is sent as effectively. In 8051 MCU, the telemetry module will be software implemented, and bidirectional communication between the PC and the MCU will be used to ensure a good data transfer. Moreover, it is used at the output of the MCU to display the correct output.