The following information is a single lesson in a larger project. Find more great projects here.
In this project, you will make a moving image using a series of still images that rotate around a spindle. Not only will you use a motor to rotate the series of images, you will also be able to run the motor backwards using an integrated circuit called an H-bridge.
Step 1: Project Description
Before the internet, television, even before movies, some of the first moving images were created with a tool called a zoetrope. Zoetropes create the illusion of motion from a group of still images that have small changes in them. They are typically cylinders with slits cut in the side. When the cylinder spins and you look through the slits, your eyes perceive the still images on the other side of the wall to be animated. The slits help keep the images from becoming a big blur. Originally, these novelties were spun by hand, or with a cranking mechanism.
In this project, you’ll build your own zoetrope that animates a carnivorous plant. You’ll power the motion with a motor. To make this system even more advanced, you’ll add a switch that lets you control direction, another to turn it off and on, and a potentiometer to control the speed.
- Continue to the next step.
Step 2: Bill of Materials
You will need the following electrical components for this project:
2 10 k-ohm resistors
1 9V battery
1 motor An chip called an H-bridge ...and of course your Arduino Uno and a breadboard!
If you are using the physical Arduino kit, you will also need the battery adapter to go with the 9V battery, as well as the wooden motor hub, paper cutout, and CD to create the moving image.
Can you match each component on the list to its location on the breadboard?
Continue to the next step to learn about the H-bridge component.
Step 3: Motor Circuit
In the Motorized Pinwheel project you made a motor spin in one direction. If you were to take power and ground on the motor and flip their orientation, the motor would spin in the opposite direction.
It’s not very practical to do that manually every time you want to spin something in a different direction, so you’ll be using a component called an H-bridge to reverse the polarity of the motor.
Take a look at the circuit diagram and explanations, below.
- Just like the previous motor project (Motorized Pinwheel) the motor needs more current and voltage than the Arduino can provide. Notice that the motor is attached to two pins on the H-bridge, and the H-bridge itself is being supplied with 9 volts via a 9V battery!
- Just like the previous project, the 9V battery shares a ground connection with the Arduino.
- You will also notice a lot of wires between the Arduino and the H-bridge! Every connection is needed to control the complex circuitry inside the component. All of these digital pin connections will be explained in the instructions for the project.
- Continue to the next step.
Step 4: H-bridge
An H-bridge is a type of component known as an integrated circuit (IC). ICs are components that hold large circuits in a tiny package. These can help simplify more complex circuits by placing them in an easily replaceable component. For example, the H-bridge you’re using in this example has a number of transistors built in. To build the circuit inside the H-bridge you would probably need another breadboard!
With an IC, you can access the internal circuits through its many pins.
- It’s sometimes convenient to refer to the pins by number instead of function. When looking at an IC, the part with a dimple is referred to as the top. You can identify pin numbers by counting from the top-left in a “U” shape like the picture above.
- Continue to the next lesson to learn how to set up the circuit!
Next Lesson:Setting Up the Circuit