Making the boat (I)
Using Makerbot 3D printer to print out a boat (12x5x3cm), a pair of paddles and a flotation device.
credits to http://www.thingiverse.com/thing:641115
boat with flotation device
Making the boat (II)
Mount the motor onto the flotation device and mount two pegs on the sides of the boat, connect them with an axle and a gear in the middle. Then, attach the peddles on the two sides of the axle.
Challenge & Iterations: At the beginning of the project, we tinkered the boat by hacking a toy boat. We disassembled the toy and attached motor, gear, and paddles on it with rubber bands. It turned out that the boat is too heavy, so that we cut some Styrofoam following the boat’s shape to give it more buoyancy. After a few trials, we had problems with the boat, such as leakage and boat being unbalanced; therefore we decided to make our own boat out of 3D printing.
The first version of our boat
Study the mechanism by wheels at the beginning of the project
Making the control room
Cut a paper cup in half and attach it to bend sensor. Fix a bend sensor, power, battery and a bargraph to a mounting board. The reason to have the bargraph is to monitor how much energy is supplied to the boat.
Challenge & Iterations:
In the beginning we had a washer in the cup to make it ergonomic. Then we realized that it couldn't limit the movement of the cup effectively. In the end we used two pieces of strings to hold the cup in place.
Making the water channel
Make a water channel however you like as long as you can fit the boat into the channel. We drew the expended view of the water channel (box) in Inkscape. We imported the file to a laser cutter. Five pieces of acrylics were cut out of an acrylic board that is 5mm thick. They were assembled by chloroform (professional is suggested since chloroform is very toxic). Apply silicone glue along the edges to prevent leakage then wait for 24 hours.
Making the finish line (I)
Find a piece of cloth to use as your national flag. Our flag is about 11cm x 8 cm. Use double-sided tape to attach your flag to a stick (19cm). Replace the button on the switch with a double-headed switch. Connect the flag to a Littlebits’ motormate, also, make sure that the end of the flag does not exceed the motormate. The reason for replacing the button is to make sure that the flag is up-right. Connect a switch and an inverter to one side of a double AND module then connect a DC motor to the other side. Create a 3D printed part to place the inverter and switch perpendicular to the motor and the double AND.
Making the finish line (II)
Connect a motion trigger to the part built in Step 5 by using a fork that is connected to the battery. Also modify the motion trigger so that it will only pick up motions directly in front of it by covering up the sides of the trigger.
Challenge & Iterations: Our initial idea was to make the boat pop a balloon that contains glitters. When the balloon pop, a sound sensor will be triggered which will raise the flag. During the process we tried many ways to pop the balloon, including using a sewing needle, medical needle and making the boat row faster. The balloon is still living happily up to this day. Due to the perseverance of the balloon we decided to use a motion trigger instead.
Another process we’d like to mention is the iteration of the logic gate.
We started with the double AND, sound trigger and switch. We used an inverter to make sure that the switch starts with the on position even when the motor is off. When the sound trigger turns to the on position then an electric current will flow through the double AND logic gate which will allow the dc motor to start rotating.
Connecting the parts
Now we have parts for 1.) The boat 2.) Control room 3.) Water channel 4.) Finish line. It’s time to combine everything together. Attach the control room to one side of the water channel. Drill two holes (3mm diameter) on the water channel to attach the mounting board. Connect control room to the boat with wires from littlebits. Depending on the length of the water channel you can choose how many wires to use. If you using more than one wire you can consider adding a piece of Styrofoam underneath the wire connection joint. Connect the flag, DC motor, switch modules and add them onto a mounting board. Attach the mounting board on the opposite side of the water channel. The motion trigger will not work through acrylic; therefore, we need to have it mounted higher than the water channel.
Challenge & Iterations: We realized that the boat can’t row smoothly because of how hard the wire is. So we decided to add a bridge over the water channel to support the wire, however the bridge idea did not work due to the friction of the wire. We ended up using a piece of Styrofoam to float the wire joints. We had considered using wireless modules, however due to the weight of the battery and cable, we decided to keep our current design.
Play Ai Dai Wan - Exhalation Game
You will need to row the boat by blowing into the cup. Keep the boat going at constant velocity by blowing steadily into the cup. There are many other strategies and techniques but those are for you to figure out ☺