Here's another totally low-fi project I built with my son one weekend. It's a remote controlled boat using Arduino and the very cool MIT App inventor. As you can see the boat itself is really clunky as we love to build out of what we have. You can attach this project to any floating object. The more lightweight the better (the playmobil viking boat was pretty heavy). Also you could look at using a rudder instead of an air fin for steering, would definitely be more responsive.
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Step 1: Parts
Here's a general list of parts. There's probably a combined arduino and bluetooth out there but I didn't use one.
- Arduino Uno (adafruit $25)
- Bluetooth sheild (adafruit $25)
- Motor shield, servo & motor (adafruit has a kit with motor, servo and sheild for $42)
- Battery packs (adafruit 9v $4 and adafruit 4xAA $3)
- MIT App Inventor App on a smart phone (you can access the app I created here and then copy it and customize it)
- A boat and some sort of waterproof enclosure (I used a totally ridiculous playmobil boat and tupperware that can seal tight
- Hot glue gun (the universal friend of sloppy makers).
- jumpers, electrical tape, a breadboard, drill bits, misc tools and supplies
Step 2: Assembly
We put the guts (arduino and sheilds) into a lunch box and sat some battery holders on top (so as not to overbalance it). You can see in the pictures that we made this an outrigger, because the playmobil boat was not very seaworthy. I suggest starting with something a bit more suitable. However my tupperware outriggers did quite nicely in the end.
For the fan, we took a dc hobby motor, glued it to a bolt that was glued to the deck. We hand drew a fan and cut it out of an old take out container, then heated the vanes to angle them. As with this whole project had no clear sense it would work and it did. Score one for leaping before looking!
We went with a servo mounted on back (lots of hot glue there) with a vertical fin that directed the air flow from the fan. When we built it we had no idea if it would be enough to make a difference, but it really worked well. Inverting this and creating a rudder would have probably worked better and we might try that sometime soon.
Step 3: Code
Code is pretty basic. Just a few calls for bluetooth to direct the servo one way or another and to make the motor spin forward or backwards. The MIT App inventor is really easy to use and amazingly quick to prototype something like this.
Attached are the code for the arduino and also the MIT App Inventor code . I've also included the arduino code as a text file.
Refinements could include a slider for the angle of the fin or the speed of the motor.
Step 4: Sail Away
That's about it. We took it down to a creek and it sailed along really easily. Pretty responsive and fast. Not great in stronger currents, but I'm sure a lighter frame etc could do better.