MTek MIP-12 is the end deliverable I produced for a senior capstone design class at the end of my undergraduate degree programme. It is a modular platform for biomedical instrumentation experiments designed to allow for the safe development and application of electronics for medical instrumentation devices. I came up with the idea for MIP-12 when I created an EKG and multi-channel EEG on printed circuit boards. This project is the end result of my efforts to make these devices safe and allow future expandability of the instrumentation suite I began creating.
These are the PCBs for the signal interface.
The Modular Instrumentation Motherboard provides power to each daughter card through a regulated power bus. The motherboard also includes a 12-channel ADC, microcontroller, and two isolated USB interfaces.
Shown in this photo are one single channel EKG and one two-channel EEG daughter card. There is space for six daughter cards total in the enclosure. Note power/signal-out cables attached to each board. Standardisation of the input interface came after these two boards were developed. I created a backwards-compatability adapter to ensure they may still be used.
In the assembled MIP-12, the front panel connects with the various sensor daughter cards using three IDC cables and a breakout board (breakout not shown). The power switch is intended to be wired to a soft on/off for power cycling the motherboard.
In this photo are two medical-application approved isolated power supplies with line isolation of over 10kV. They meet the IEC standards for wall power connected devices used in medical applications. Behind these power supplies is a supply regulator for the old MIP-12 generation 1 signal interface used in the EKG and EEG displayed above.
The Outer Case
A finished product requires a professional enclosure to contain all the electronics. One of my design requirements was to make the enclosure out of non-conductive material. Of the options available, I decided to make the enclousre out of wood because it is easily engravable.
The front of the case, with room saved for an optional LCD display. The front panel houses twelve connectors used for electrode arrays for each signal card. I implemented a status indicator with ten LEDs controllable with a digital bus connection from the motherboard.
The rear of the case is where the device is powered from a line cord, and connected to a computer over USB to receive signals or update motherboard firmware. There is also space for a 92mm fan for cooling the enclosed electronics.
In this photo you can see how the power supply, motherboard, and daughter card panels are mounted in the enclosure. This photo also shows a debugging header connected to the motherboard through the fan mounting area of the rear panel.