How to Build a Cardboard Robotic Arm
Building a cardboard robotic arm is a popular science project in schools around the world. It is a simple, first step in robotics education. Students are given assorted supplies and asked to construct their cardboard robotic arm using only their creativity and ingenuity. Students are expected to finish the project in widely differing ways.
The Cardboard Robotic Arm Project
The cardboard robotic arm experiment is designed to develop the problem solving skills in students. It also helps develop teamwork. Students are divided into small groups and told to work together. Since they are given no further instruction, it is up to them to figure out how to build a cardboard robotic arm through trial and error with the components given to them.
Cardboard Robotic Arm Dimensions
The only requirements for the cardboard robotic arm is that it must be at least 18 inches in long and be able to pick up something. This is usually a small ball or cup. The basic project involves everyday household materials and is intended for school aged children ages 8 to 18 years old. More advanced versions of the exercise introduce hydraulics with the use of syringes, tubing and water. Another version allows electronic components to power the cardboard robotic arm. These are intended for advanced high school science students and college students.
Cardboard Robotic Arm Components
Supplies given to students in the basic cardboard robotic arm project are:
5 strips of cardboard measuring 3 inches by 22 inches.
10 scraps of cardboard of assorted sizes
4 feet of twine
4 feet of fishing line
15 rubber bands of assorted sizes
1 roll of masking tape
1 roll of clear tape
6 clothes pins
8 binder clips of assorted sizes
2 clothes hangers
15 paper clips of assorted sizes
10 small wire nails
15 popsicle sticks
The students are intentionally given a wide variety of supplies so they have to choose which ones are best for the job. It teaches them to think outside the rigid constraints of detailed directions. Cardboard robotic arm projects involving hydraulic and electric power involve more supplies for the students.
Building the Cardboard Robotic Arm
Every cardboard robotic arm will be put together in a slightly different way, but they will all have the same basic elements in common:
The cardboard robotic arm must have a sturdy base. If it is not secured it will topple over when it attempts to pick up the object.
The cardboard robotic arm must have at least two parts to the limb. These are generally referred to as the biceps and the forearm. Some cardboard robotic arms also have hands or fingers.
The cardboard robotic arm must have at least two joints. The elbow joint enables it to bend over to the object. The wrist or finger joints allow it to pick up the object. Some cardboard robotic arms also have a third joint at the shoulder near the base.
The cardboard robotic arm must have a muscle system. This powers it through its motions. This can be human muscle pulling strings, hydraulics pushing liquid or electricity sending impulses to motors.
The Cardboard Robotic Arm Base
Students are given far more cardboard than they need to build an arm measuring 18 inches. The bulk of this cardboard must be used to provide stability for the cardboard robotic arm base. The tape can be used to piece together the random sized cardboard pieces. Binder clips, clothes pins and coat hangers can give the base form and weight. They can also secure the base to a table or other object if that is allowed. Any left over supplies should be used to weigh down the cardboard robotic arm base. Mount the arm far to one side leaning over the base.
The Cardboard Robotic Arm Limbs
The supplies provided make it easy to create a cardboard robotic arm 18 inches long. The problem lies in the strength of the arm. A single strand of cardboard will likely fold and collapse if made to pick something up. The 22 inch lengths of cardboard can be folded in half and used for the cardboard robotic arm limbs. Give them added strength by reinforcing them with the popsicle sticks and pencils. You can also use a bent coat hanger.
The Cardboard Robotic Arm Joints
The cardboard robotic arm joints must be strong yet flexible. The small wire nails can be driven through the elbow joint and bent on the other end. This will allow the cardboard robotic arm to move up and down while holding it together. Another option is to pierce the joint all the way through with a pencil and use it as the elbow joint. The clothes pins and binder clips work well for the fingers. Attach them to the end of the cardboard robotic arm.
The Cardboard Robotic Arm Muscles
The cardboard robotic arm needs power to perform its task of picking up an object. This can be provided in three ways that are dictated by the rules of the particular experiment. They are:
- human power
- hydraulic power
- electric power
This is the simplest way to control a cardboard robotic arm. A series of strings must be set up within the cardboard robotic arm to make it work. Use the twine or fishing line to mimic muscles. They must be wrapped around the joints in a way that the operator can pull them and make the cardboard robotic arm move. Have different strings perform different functions. This is what the human body does. Different muscles control different movements. Have one string move the arm forward and back. Have another string bend the elbow. Have a third string release the fingers. It may take some practice to operate, but the cardboard robotic arm should function similar to a human arm.
For hydraulic power, a series of water filled tubes are strung along the cardboard robotic arm. Water is forced through the tubes with syringes. The water can be channeled to different tubes performing different functions just like the human powered model. However, since the tubes are interconnected, all these functions are performed at once. This requires a great deal of experimentation and tinkering to get the movement right.
Electric powered cardboard robotic arms use wires instead of tubes, but the principle is the same. A battery is usually the power source. A button on a switch releases the electric current. The wires carry the electric impulse to motors that move the cardboard robotic arm. As with the hydraulic model, a lot of adjustments need to be made to make an electric powered model work smoothly. The problem tends to be controlling the power. The cardboard robotic arm may jerk violently when the electricity is released.
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