Building a semi Smart, DIY boat with Arduino and some other sensors

Picture of Building a semi Smart, DIY boat with Arduino and some other sensors
I based this off of this really nice post for building a water bottle boat, with some additions for obstacle avoidance and light-guided control. I used Arduino as a microcontroller, an ultrasonic sensor in the front, a few simple switches on the side of the boat, and a few light sensors on either side.  See here for a few more photos or here for a pdf step by step.

This simple little floating boat bounces off walls, can be steered with a flashlight, and won't hit something head-on. 

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Picture of MATERIALS
hot glue + glue gun (silicon optional)
two small DC motors
two water bottles
two small propellors
arduino + USB cable + computer
wire strippers
a plastic box 
a 9V battery + a connector
a power diode (like 1n4004)
some resistors
 a soldering iron + solder
a MOSFET transistor or TIP 120
2 few switches + 2 photocells

Step 2: Put the motor in the cap

Picture of Put the motor in the cap
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1. Take off the top of both water bottles
2. Poke a hole in each cap
3. Apply hot glue to the inside of the cap, but not on the hole. Slip the motor shaft through the hole. When dry, the shaft should spin freely. 

Do this with both bottle caps and motors. 

Step 3: Tape the water bottles together

Picture of Tape the water bottles together
Use two or three strips of tape to tape the water bottles together, sort of like a raft. 

Step 4: Solder leads to the dc motors if there are none

Picture of Solder leads to the dc motors if there are none
The motors are now attached to the bottle caps.

Solder on long (about 10") leads to the motors, if there aren't any.

Step 5: Cut a slit in the water bottle

Picture of cut a slit in the water bottle
Cut a small slit in each water bottle. 
This is the hole through which the wires from the motors will poke through. 

Step 6: Put on the cap and feed through the wires

Picture of put on the cap and feed through the wires
Put the cap on the bottle and feed the wires into the bottle opening, then out the slit that you just made. If you have trouble screwing on the cap, use some hot glue to secure it. 

anood.aydha17 days ago

I tried to do this project with two 3V DC motors and used a 9V battery to power the Arduino. However, the 9V battery drained fast in about 10 minutes when the Arduino is running the 3V DC motors through the 3.3V pin, how can I solve this problem?

kinetike2 years ago
Haha, I hate this kind of spaghetti! Good job on this creation and your SNEEL! Love them both.
Kinnishian2 years ago
I'm a bit fan of the simplicity. I'm surprised the hot glue trick works for the motor-shaft. Definitively a tip I'll be trying to store away and remember.
alcurb2 years ago
Nice project.

You have a picture when its floating? I'm trying to picture it floating and wonder if the water leaks through the motor shaft holes, unless the shafts remain above water. How do the bottles remain air/water tight with said shaft holes?

I would like to see a video showing how it moves under its own control.
I race fast electric R/C boats. We put lube in the stuffing box (the tube the prop shaft goes through). I don't know of anyone who has had a problem with water entry through the stuffing box if the lube was applied properly.
N.fletch2 years ago
I'm sorry for asking a petty question: but how did you create the nice design of the arduino with the wires and other misc. components. I've seen other authors add these to their "ables". I would like to know so I could create my own.
Great instructable by the way!
Thank you peptidefarmer
janw2 years ago
Very nice project! And very good recycling of materials.
wkg78221422 years ago
where code?
love your project... good use of on hand materials... nice job