We decided to build our robot to be like the Cat in the Hat from the children's book. We started by drawing out our sketch and talking about what materials that we wanted to use. If you desire to build a different character, or simply make a box robot without decoration, feel free to use this tutorial for the basic elements of building a recyclable robot that can strum a ukulele.
The materials are listed below:
Hummingbird premium kit (we used the servo, the motor, and the hummingbird duo)
Three 8 oz. water bottles
Red 3M tape
Plasma cut weight piece (tail)
Hot glue gun
Pieces from Hexbug by vex to create the arm
4 Screw Hooks
About a yard of string
Step 1: Sketch It Up
The sketches show the rough idea we had of keeping the cat in the hat with a square body. Two stationary water bottles are the feet which are full of water to help keep it stable. There is one water bottle for the head that is empty and rotates left and right to make it appear like it was turning its head. The sketches also include the rough dimensions for the ukulele that we programming the arm to strum.
Step 2: Build That Body
We used a cardboard box as the main body and other household items, like water bottles, to make the head and the legs. We cut five holes in the box: two for the feet, two for the arms, and one for the head.The first two pictures show the hole for the servo and the holes for the feet. They also show how we attached the servo by using hot glue. For the feet, that are seen in the last picture, we used 8 ounce water bottles and left the water in them so that they would be stationary and heavy enough to help support the robot. In the second picture, you can see how we super glued the tops of the water bottles into the holes on the bottom of the box. The third picture shows the box and the hole that is on the top. The last picture shows the inside of the box and how we connected the parts to the inside of the box and mounted everything. We used hot glue to attach everything and left the wires inside of the box in order to control the robot using the hummingbird.
Step 3: Form the Cat DNA
At the same time that one person was working on the body of the robot, other people were working on the code for our robot. We had decided that we wanted to make the head spin and the arms move in hopes of the cat in the hat looking like he was playing the ukulele. The program that we are using for the code is called Snap and it is a drag and drop block programming software that can be downloaded and used following this link. Snap allowed us to customize the movement of our robot. The picture shows the code that we made for our robot and each section is just as important as the other. The section on the top left is the command that makes the robot stop after the other commands of the heading spinning and the arm moving to play the ukulele have had time to go through. The motor controls the movement of the head and the servo controls the arm movement.
Step 4: Give the Cat a Heart
To connect the hummingbird to the robot, we started with the plain hummingbird board and attached the servo using the red, black, and yellow cords and lined it up with the B, R, and Y prongs. After we attached the servo, we attached the motor in the orange sections with the orange cords. It doesn't matter which cord goes into which side. There is also a cord that connects the hummingbird to the computer that needs to be connected and a cord that connects the hummingbird to a power source. To connect it to the inside of your Cat in the Hat robot, simply use the installed motor and servo wires and connect them to the hummingbird. The entire board with the AC adapter cord and USB cord can all fit nicely inside the bottom of the box, with the two cords coming out at one of the corners (this allows the box to fully shut, see last photo).
Step 5: Make It Purr-ty and Stable
We made a tail and hat for our cat in the hat to make it look more realistic. The hat is made of roll up paper and red tape and the tail is made out of a piece that we cut using the plasma cutter and some pipe cleaners to make it look like a tail. The hat is attached to the head by using super glue. We also added a bow tie to the front on the box like the cat in the hat has. The tail is made out of metal in order to counter balance the weight of the ukulele that we are going to put on the front on the robot. The tail was not heavy enough to balance out the weight of the ukulele so we had to add an extra weight piece to the inside of the box. The tail weighed 139.4 grams and the extra weight piece weighed 156.6 grams. This weight was purr-fect.
Step 6: Make It Strong
To attach the ukulele, attach the screws to the back of the bot after putting down small support blocks with glue on the inside. These screws will allow you to string up the ukulele in place to allow the arm to strum. To build the arm, we used pieces from the hexbug Vex kit. We didn't have a plan for what the arm was going to look like, we just played around with the design until the arm fit around the ukulele in front and easily could attach to the back of the circular shoulder joint. After the design fit, we screwed the vex arm onto the joint and tested the movement. The setting was 180 degrees and the arm went all the way around and broke apart. After realizing the error of having a high angle in the servo program, we re-programmed in snap to move only 60 degrees, allowing the arm to strum the bottom note and function well.
Step 7: Finish It Up
After following all of these steps, you should have created a recyclable robot!!! If for some reason it doesn't work retrace your steps and do some problem solving! Also, be creative and make it your own by changing some things, or add more motors and parts now that you see the basics of Hummingbird Duo robotics!
Step 8: What We Took Away
What our group was able to take away and learn from this project is that even when things don't work right the first time that it doesn't mean you won't be able to figure it out. Our code gave us a little trouble and so did the weight of the ukulele on the front of the box. We were able to start back at the beginning of those steps and figure out how to fix it.