Patrick McGuire's Portfolio

Circuit Board Design

Rocketry Dual Deploy Altimeter

High power amature rockets typicaly deploy two parachutes: a small one at apogee, and a second large one close to the ground. This most commonly done by igniting black powder charges with electronic matches. This board will control these deployments by powering the matches.

The board contains a SAMD21 microcontroller, a barometer (for measuring the rockets altitude), an accelerometer+gyroscope, 8KB FRAM for storing configuration and state, 64 MB FLASH for black box logging. It has two switched power channels for firing the charges. It has usb/battery power switching, and ideal diode reverse polarity protection. All components are tested and worked, software is currently being developed.

Front of the altimeter

Back of the altimeter

ATSAMD21 Microcontroller Development Board

Microcontroller Development Board

To get familiar with designing circuit boards with microcontrollers, I designed a basic development board for the ATSAMD21 microcontroller. This design is based on common Arduino boards, and was programed using the Arduino software and bootloader. I got the boards assembled professionally.

The board worked great, and I have multiple more complicated projects planned using the same microcontroller.

Magnetic Switch

For the aerospace club at Northeastern I designed a magnetic activated switch. This allows rockets to be powered on without opening them up. Putting the north pole of a magnet near the switch would latch the switch on, and the south pole would latch it off. It had a power-on-reset circuit, so that the state would be guaranteed in the case of a poor connection or momentary loss of power.

This was my first experience working with an assembly service, and it came out great!

Top of the magnetic switch

Bottom of the magnetic switch

Power switching and monitoring PCB I designed

Power switching and blind mate system assembled

Power Switching and Blind Mate System

For the coral reef monitoring robot I worked on at Woods Hole Oceanographic Institution, I designed 3 circuit boards to simplify the vehicle's electrical system. The power board handled power distribution, switching, regulation and current draw monitoring. The blind mate board allowed the electrical chassis to be removed from the robot easily for servicing.

Sensor Breakout Boards

While working at Woods Hole Oceanographic Institution a group I was working with was trying to use GPS in a upcoming field deployment, but struggling with getting reliable data. I designed a circuit board small enough to fit in a tiny pressure housing that contained a GPS receiver, antenna and backup battery. This project was a 1 day turnaround from start to sending parts out for manufacturing, ultimately providing a significant performance increase in time for the field work.

Similarly at Apeiron Labs there was an issue with a barometer in their robot. I designed a breakout board with better thermal isolation to improve accuracy. This project was also a 1 day turnaround from start to sending parts out for manufacturing.

Barometer breakout board

GPS receiver circuit board

Second generation backplane

First generation backplane

My home built ROV

ROV Backplane

My first robotics project ever was a small underwater ROV (remotely operated vehicle) that I built with my brother.

In order to package the electronics cleanly inside the small electronics housing I designed a circuit board that contained current and voltage monitoring, power distribution, power switching for lights, voltage regulation, and indicator lights.

Later, I designed a second revision of the board, which was used successfully on by brother's college capstone robot in multiple places.

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