I Like to Move It: Motorizing a Robot Hand *
|Time Required||Long (2-4 weeks)|
|Prerequisites||Once the hand is assembled, adding the servo motors, connecting the microprocessor, and writing the code for the microprocessor will require familiarity with a hobbyist microprocessor board (like ones using ArduinoTM, PIC®, or similar). The student should be comfortable with connecting, programming, and testing projects on these boards.|
|Material Availability||Readily available|
|Cost||High ($100 - $150)|
|Safety||Adult supervision is suggested for parts of this project. Use caution with sharp knives, glue, and soldering. Low voltage (from a battery or power supply) is involved.|
AbstractImagine how cool it would be to have your own motorized robot hand. Well, stop imagining and turn that daydream into reality! Start out by designing and building a robot hand. The Science Buddies project Grasping With Straws: Make a Robot Hand Using Drinking Straws shows you a simple way to make a robot hand with drinking straws, or you can design a robot hand from any other materials you think are suitable. Your hand design will need sewing threads, or some other mechanism, for motors to act on and move, causing the fingers to flex. See Figure 1 for an overview of the key materials for this engineering project.
Figure 1. For this robotics engineering science project, you will need a robot hand (similar to the straw robot hand shown here or any other design you fancy), a microprocessor board like the ArduinoTM shown here, and several servo motors, such as the one shown removed from its box.
Once you have your robot hand, you will need to add small servo motors. Servo motors are capable of doing all sorts of useful work, as they do every day in toys and household appliances. For instance, your DVD player ejects discs using servos; toys employ servos to steer (cars) and walk (robotic pets). The list is almost endless. You will need one servo motor for each finger and movable joint on the robot hand. Servos come in many shapes and sizes, so you will have to think about what might work best for your hand design. A good starter servo is the standard-size Futaba® S3003 servo sold for radio-controlled cars (available from Amazon.com). You may also get some ideas and suggestions at a hobby store. You can read more about servo motors in the Science Buddies Introduction to Servo Motors.
Make sure your robot hand is attached to something that can support all the necessary servo motors. We'll refer to that as the "robot arm." When you are ready to mount the servos to the robot arm, look at the round plate or bar that comes attached to the servo motor shaft. This is the servo horn. Consider how this will rotate when the servo moves, and mount the servos so that one of the holes in the servo horn will get closer to or farther from the hand as the shaft rotates. Tip: It is best if you can arrange things so that the threads (or other control mechanism) from the robot hand do not cross. Servos usually mount with screws into a servo mount, but you may find it easier to glue wooden blocks to the robot arm and screw the servos to those. We do not recommend gluing the servos directly to your robot arm assembly.
To control the servos, you will need a hobbyist microprocessor board. Boards of this type include all of the circuitry you need to make simple computer projects and program them from your personal computer. An ArduinoTM is a popular board that uses Atmel® processors, is easy to program, and has a lot of widely available help resources (see Bibliography). The ArduinoTM UNO is one of the most popular boards for getting started (available from Amazon.com). You can learn more about Arduinos and how to use them on the Science Buddies Getting Started with Arudino page. Another good alternative is a board based on the Microchip PIC®. One good PIC® board to consider is the SBC44B from Modtronix.com. As you get more comfortable programming microprocessors you may find the PIC to be a more capable processor than the Arduino. Whichever board you choose, you may find it easiest to connect the servos to your board, write a short test program to activate the servos, and see how they move before you attach the robot hand threads (or other control mechanism) to the servos. Free Microsoft Windows® software for programming an ArduinoTM is available on the web and Microchip offers free PIC® programming software on its website at http://www.microchip.com/development-tools. Tip: When attaching the threads, you want to have little or no slack but not have them pulled so tight that the fingers of the robot hand are curled.
Now you are ready to write the code to make the robot hand move the way you want. You may have to experiment with different amounts of rotation so that you don't pull the threads too hard. Go slowly and try different values until things work. Learning a little about pulse width modulation, or PWM, may be helpful. A logic analyzer and/or oscilloscope may also be helpful tools for troubleshooting if you have access to them. What surprisingly human-like actions can your hand perform? Can it play the piano? Pick up and sort small items? In the end, what fun and useful things will your robot hand be able to do?
Howard Eglowstein, Science Buddies
Cite This PageGeneral citation information is provided here. Be sure to check the formatting, including capitalization, for the method you are using and update your citation, as needed.
Last edit date: 2017-07-28
- Eglowstein, Howard. (n.d.) Introduction to Servo Motors. Science Buddies. Retrieved February 4, 2013 from www.sciencebuddies.org/science-fair-projects/project_ideas/Robotics_ServoMotors.shtml
- Eglowstein, Howard. (n.d.) Getting Started with Arduino. Science Buddies. Retrieved February 4, 2013 from www.sciencebuddies.org/science-fair-projects/project_ideas/Robotics_Arduino.shtml
News Feed on This Topic
Ask an ExpertThe Ask an Expert Forum is intended to be a place where students can go to find answers to science questions that they have been unable to find using other resources. If you have specific questions about your science fair project or science fair, our team of volunteer scientists can help. Our Experts won't do the work for you, but they will make suggestions, offer guidance, and help you troubleshoot.
Ask an Expert
If you like this project, you might enjoy exploring these related careers:
Robotics EngineerHave you watched "The Transformers" cartoon series or seen the "Transformers" movies? Both shows are about how good and evil robots fight each other and the humans who get in the middle. Many TV shows and movies show robots and humans interacting with each other. While this is, at present, fantasy, in real life robots play a helpful role. Robots do jobs that can be dangerous for humans. For example, some robots defuse landmines in war-stricken countries; others work in harsh environments like the bottom of the ocean and on the planet Mars. At the heart of every robot is a robotics engineer who thinks about what a robot needs to do and works with several engineering disciplines to design and put together the perfect piece of equipment. Read more
Mechanical EngineerMechanical engineers are part of your everyday life, designing the spoon you used to eat your breakfast, your breakfast's packaging, the flip-top cap on your toothpaste tube, the zipper on your jacket, the car, bike, or bus you took to school, the chair you sat in, the door handle you grasped and the hinges it opened on, and the ballpoint pen you used to take your test. Virtually every object that you see around you has passed through the hands of a mechanical engineer. Consequently, their skills are in demand to design millions of different products in almost every type of industry. Read more
Robotics TechnicianRobots are no longer futuristic machines. Robots are here and now and are used in manufacturing, health care, service industries, and military applications. They perform tasks that are repetitive and hazardous—things that humans don't want to do or are unsafe to do. But robots are still machines, which means they require humans to build, maintain, program, and keep them functioning efficiently. Robotics technicians work with robotics engineers to build and test robots. They are responsible for installing and maintaining robots and keeping them in working order for their employers. If you are interested in working with robots, your future is here and now. Read more
Biomedical EngineerShakespeare described humans as a "piece of work," and others have called the body "the most beautiful machine," but like any machine, sometimes body parts need repairs or servicing when the body cannot take care of the problems itself. That's where biomedical engineers come in. They use engineering to solve problems in medicine, such as creating replacement body parts, drug-delivery systems, medical instruments, and test equipment. Their work helps restore health and function, and improves the quality of life for people who are sick or injured. Read more
News Feed on This Topic
Looking for more science fun?
Try one of our science activities for quick, anytime science explorations. The perfect thing to liven up a rainy day, school vacation, or moment of boredom.Find an Activity
Explore Our Science Videos
BlueBot 4-in-1 Robotics Kit
Slippery Slopes - STEM activity
Gel Electrophoresis and Forensic Science: Biotechnology Science Fair Project