n3m02 the Autonomous Boat: Depth Surveys

catamaran version of n3m0 the boat

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!

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Lawnie the Remote Controlled Lawnmower

Back in 2019 I made a remote controlled lawnmower. It is not a very original design, it follows closely the mower from Make Magazine and many other youtube videos, with some modifications to suit what parts I could get. I got an electric wheelchair and an electric mower second-hand, bought a speed controller and some relays, and made my own RC controller and receiver with arduinos and nRF24L01 radio set. I tried my best to keep the cost low, using as many second-hand parts or things I already had in my shop. This mower has been mowing my lawn ever since, and makes a tedious chore fun! I highly recommend building one if you still push a mower yourself.

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