I designed the 3D models in this project using an open source application called FreeCAD and a metric ruler. I learned how to use FreeCAD by following a few tutorials for beginners I found on the introduction screen when you start the program. When I started the robot frame, I wanted the end product to to be sturdy, have very few parts, and have few to no bolts or screws. This is why I designed 3d printed pins to hold the servos in place. Once the frame was done, I designed the wheels so the top of the ServoBot would be level and to accommodate most 4 point horns that come with standard size continuous rotation servos. After more than 20 design modifications, I created a one piece frame that would hold two servos, ball bearing, battery harness, and circuit board with holes for cable management. I also designed a sleeve and cap for the IR LED's to save even more money on parts. Overall, I am very happy with the design and have already tested the platform with students and it performed well. Students and parents are very pleased with the robots and I will continue to use them in class. There are two disadvantages I have found with this design. First, once the circuit protoboard is placed on the top of the frame, it cannot be removed. So, if the frame becomes damaged, you must replace the frame and protoboard. Second, the pins designed to hold the servos in place are one shot devices--if you have to take them out, they must be replaced. Make sure you print extra pins. Overall, I am very happy with the design and how it has performed.
Overview & Background:
The purpose of this project is to give fellow educators an affordable robot platform for students at their school, youth group, or club to build, program, and experiment. After teaching students about robotics, most students wanted to take the robot home. However, the cost was too prohibitive. Once my class bought a 3d printer, I saw this as an opportunity to create a programmable robot that 1 to 2 students could build, program, and then take home and continue to learn and experiment.
As students work to complete the ServoBot, they will learn to wire an electronic circuit board, install software and connect their circuit board to the computer for testing and troubleshooting, construct the robot platform using common hand tools, and finally, program the ServoBot to use sensors and servo motors to interact in different ways with its environment.
This project is recommend for kids (5th through 12th) and adults wanting to learn more about robotics.
Computer Science, Computer Programming, Technology Education, Electronics, Robotics, Pre-engineering, Science, Physics
Skills Learned (Standards):
After completing this project, students will be able to:
Know when to wear personal protective equipment (PPE) to protect both themselves and equipment.
Safely wire and handle electronic components.
Construct an electronic circuit onto a prototype board.
Download and Install Arduino IDE onto a computer.
Connect an Arduino Microcontroller to a computer.
Upload a sketch from a computer to an Arduino Microcontroller.
Execute a sketch on an Arduino Microcontroller.
Monitor the output of a sketch from an Arduino Microcontroller from a computer.
Use common hand tools to construct a robot chassis.
Calibrate continuous running servos.
Program the ServoBot using functions to make it maneuver forward, backwards, turn in place, and turn left or right.
Program infrared sensors on the ServoBot so it can detect objects and avoid them.
Write more efficient code so the ServoBot has better performance.
Change the ServoBots behavior from avoiding objects to following objects by changing its coding.
Please refer to the ServoBot_Construction_and_Programming_Manual_8-13-16.pdf for more information on construction and programming activities.
I made this PDF file so that students could view it on a computer, tablet, or printed on paper and handed out with each kit. I wanted to make it convenient for a wide range of classes and educators to use.
If instruction and project time is limited, code can be copied and pasted into the Arduino IDE from the manual or activity code text files (located in the Thing Files Section).
Can be completed in as little as 6 hours. For more in depth coverage of programming concepts:15 hours or more.
This project can be used in:
1 day science camps
1 week science camps
Boy Scouts and Girl Scouts to help earn Merit Badges or Patches
Youth groups and Pre-Teen groups.
Please refer to the ServoBot_Bill_of_Materials_BOM.pdf for more information on the parts needed to build the ServoBot. The BOM contains links to vendors to make finding and buying these items easier. All items can be found at other places, so you can use your favorite vendor. However, pay special attention to the size of the battery holder, servo horns included with the servos, and IR LED's diameter before ordering to make sure they will fit. Also, don't forget to buy your preferred brand and color of filament.
Equipment & Tools:
Computer (Preferably one for each ServoBot)
Small diagonal cutters
Small needle nose pliers
Anti-static wrist strap.
Jeweler’s screwdriver set w/ #1 Philips Screwdriver
Smooth cut metal file
Go here to download the Arduino IDE software.
(This website is great for beginners new to the arduino. Also, it has great code ideas if students want to experiment adding additional sensors to the ServoBot.)
Rubric & Assessment:
Assessment is determined by the instructor.
Examples for scoring include:
Quality of robot construction.
Does robot perform as stated in the activities' descriptions?
Do students experiment with modifying the code to see how this affects robot performance?
Handouts & Assets:
Also included in the Thing Files Section is a:
Controller Board Schematic