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Breadboard Laboratory Interface Processor (BLIP)


CONNECT ONLY TO COMPUTERS IN THE INSTRUMENTATION LAB . WE MAKE NO GUARANTEE THAT THE BLIP WILL NOT DAMAGE OTHER COMPUTERS IF CONNECTED.

Project Overview

The B.L.I.P. project began in May 2004. B.L.I.P. stands for Breadboard Laboratory Interface Processor and utilizes the 40 pin DIP PIC16C765 microcontroller from Microchip, Inc. The goal of this project is to provide a multi-functional device that connects to personal computers via USB for students in the Bioinstrumentation course at the University of Pittsburgh Bioengineering Department. In this course, students learn the basics of electronics and instrumentation by designing, constructing,and analyzing useful devices on their own breadboards, such as audio amplifiers, differential amplifiers (for an EKG device), etc. The BLIP device, once constructed by the student, will provide the following functions:

The BLIP has USB connectivity, so the student can build the circuit, program the chip, plug it into the USB port on his/her Windows, Mac, or GNU/Linux based system, and immediately begin utilizing the different functions of the device with virtually no external software. Furthermore, the entire system costs less than $30 and can be constructed in very little time on a standard prototyping breadboard or a custom printed circuit board given to each student in Bioengineering 1310.

The BLIP Project centers around the USB capabilities of the PIC16C765 microcontroller. When the chip is connected to a Universal Serial Bus (USB) port, the computer recognizes it as a USB keyboard. This is accomplished by the Human Interface Device (HID) class definitions and descriptors written for the BLIP. The descriptors provide the information to the host computer necessary for it to write a driver for the device. The chip can then transmit all its data in the form of a code similiar to ASCII (it is not actually ASCII, but a specific code for the USB Keyboard Device Class Definitions). This approach is extremely versatile since all operating systems supporting USB 1.1 can recognize this code. A wide range of existing programs on the host computer, such as word processors and spreadsheets, can therefore receive BLIP's information, because it comes in the same form as if it were being typed on a keyboard.