Simple Autonomy With An RC Boat

[Vlad] wrote in to tell us about his latest project—an RC boat that autonomously navigates between waypoints. Building an autonomous vehicle seems like a really complicated project, but [Vlad]’s build shows how you can make a simple waypoint-following vehicle without a background in autonomy and control systems. His design is inspired by the Scout autonomous vehicle that we’ve covered before.

[Vlad] started prototyping with an Arduino, a GPS module, and a digital compass. He wrote a quick sketch that uses the compass and GPS readings to control a servo that steers towards a waypoint. [Vlad] took his prototype outside and walked around to make sure that steering and navigation were working correctly before putting it in a boat. After a bit of tweaking, his controller steered correctly and advanced to the next waypoint after the GPS position was within 5 meters of its goal.

boatgifNext [Vlad] took to the water. His first attempt was a home-built airboat, which looked awesome but unfortunately didn’t work very well. Finally he ended up buying a $20 boat off of eBay and made a MOSFET-based motor controller to drive its dual thrusters. This design worked much better and after a bit of PID tuning, the boat was autonomously navigating between waypoints in the water. In the future [Vlad] plans to use the skills he learned on this project to make an autopilot for the 38-foot catamaran his dad is building (an awesome project by itself!). Watch the video after the break for more details and to see the boat in action.

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spa sitter

Pool/Hot Tub Monitoring And Data Collection

Pools and hot tubs, although enjoyable, require monitoring and maintenance to keep the water clean and clear. [bhuebner] didn’t like having to constantly testing his hot tub’s vitals using test strips and water test kits. In an effort to autonomously monitor his hot tub’s water, he came up with a project he’s calling SpaSitter that records and tracks water quality indicators.

spa sitter The hardware is based on a Nanode (think Arduino with on-board Ethernet). Three sensors are connected to the Nanode and placed in his hot tub’s water.  The sensors measure pH, ORP and Temperature. That data is then uploaded to xively.com where the data is not just stored, but tracked over time and displayed in graph-form. Checking the vitals on your phone can also get a bit tedious so [bhuebner] set up an email notification if one of the measured data streams go outside of a predetermined range. He still has to add chemicals manually and hopes to see some automation added to the next project revision.

[bhuebner] made his code available and also posted detailed instructions, including how to calibrate the sensors, for anyone wanting to do the same thing.