Michael E. Holden
California State Maritime Academy Sabbatical Fall 2024
This report shares the results of my Fall 2024 Sabbatical project. It will get into the details pretty thoroughly, with links and files so I can find all the work in one place in the future, so feel free to skip around to the good parts. For a more visual feel you can follow the insta-blog at n3m0_the_robot_boat.
Continue reading “Surface Current Measurement and Route Optimization Using Autonomous Boats”
This report documents the transition of n3m0 the autonomous boat, originally a monohull designed for long-ish range water-quality measuring missions, to n3m02 the autonomous catamaran. The mission was to add a depth sensor to the boat so that it could survey the harbor at Cal Maritime. The harbor silts in pretty quickly and it is an expensive and time-consuming process to dredge, so keeping tabs on the depth over time was the goal. A transom-mount NMEA-1083 speed/depth/temperature transducer was added to the boat, and a raspberry pi was used to log the position of the boat from the autopilot and the depth from the sensor. The data was uploaded in real time to github, which worked quite well! Eventually a second hull was added to allow differential thrust and improve maneuverability when running next to docks and moored vessels. Read on for more information!
Continue reading “n3m02 the Autonomous Boat: Depth Surveys”revisited after 20 years! by Michael E. Holden
Continue reading “Low-Cost Autonomous Vehicles Using Just GPS”Sometimes students or other nice people ask about my Ph.D. thesis. Probably just being polite. Well, here it is.
I earned my Doctor of Philosophy in Aeronautics and Astronautics from Stanford University in 1999
Continue reading “Ph.D.”I built N4N1 to learn the details of the ardupilot sailboat firmware. I have had a few student groups building similar vessels at work, and thought it would be worthwhile to go through the exercise myself. Plus I had a boat gathering dust that needed a job.
N4N1 uses the ardupilot sailboat firmware on a Matek flight controller, with external GPS, compass, and wind vane.
N4N1’s hull was designed and built by me in the previous century, and with the rig from an RC Laser, she sails autonomously on San Francisco Bay.
Continue reading “N4N1 the Autonomous Sailboat”
This project documents how to make a windvane to sense the wind direction. It was designed for an autonomous sailboat but could be used in other applications. The structure is mostly 3D printed and uses a gopro mount to attach to the hull. The main sensor is a magnetic encoder that outputs an analog voltage in the 0-5V range. For my application I used a voltage divider to bring that down to 0-2.5V because my autopilot is based on 3.3V logic. I also have an arduino program to output the vane angle as NMEA 0183 serial data; I don’t use this on my boat but it is a standard digital interface that might be helpful for others.
Continue reading “Electronic Windvane”This is mostly just to link the video I made. It shows how to run mission planner (ground control station) and start a simulation of an autonomous sailboat (SITL), and how to run the boat in autonomous modes, including tacking parameters and geofencing. Enjoy!
Dumbo is an autonomous research vessel constructed by students at Cal Maritime. Dumbo carries temperature, salinity, and dissolved oxygen sensors and makes oceanographic observations in the waters off of the Cal Maritime Campus. This work has been supported by the CSU Council on Ocean Affairs, Science & Technology (COAST).
n3m0 is a small 3-D printed autonomous boat. It was originally documented over at hackaday.io as part of the hackaday prize contest. It’s been used for a number of projects since then, mostly documented on this website, such as n3m02 the Autonomous Boat: Depth Surveys, Ardupilot with Mobile Data Telemetry, and Surface Current Measurement and Route Optimization Using Autonomous Boats.
I won $1000 in the hackaday prize! Actually $2000!
Someone else is already building another one
Continue reading “n3m0 the autonomous boat”If you’re looking for my old site, sorry it got hacked and had to be put down.
You can email me (mholden at csum dot edu) if you are trying to find something specific.
