A pendulum is a weight suspended from a pivotso that it can swing freely. When a pendulum is displaced sideways from itsresting, equilibrium position, it is subject to a restoring force due togravity that will accelerate it back toward the equilibrium position. Whenreleased, the restoring force combined with the pendulum's mass causes it tooscillate about the equilibrium position, swinging back and forth. The time forone complete cycle, a left swing and a right swing, is called the period. Theperiod depends on the length of the pendulum, and also to a slight degree onthe amplitude, the width of the pendulum's swing (From wikipedia) .
I made this device to verify that this formula is correct.T=2π√(L/g). I used 3 swing ball, which the length of pendulum are different, a 9CM,16CM and a 25CM.
I used 3 laser module emitters to shoot the laser on the 3 Grove – Light sensor. And when the swing ball reaches the equilibrium position, the ball will cover the laser. we can measure the period of simple pendulum by reading light sensor value.
By the time you’re done with the project you will reap the following experience:
Now, let’s get started.
I did some work on structures just as the picture below shows. It’s made up of 6mm plywood. My friend from seeed help me cutting the plywood. I guess you don’t have a laser cutting at home, you can find some in the hacker space near from you easily. If there's no hacker space nearby, you can try the Laser Cutting Service supply by Seeed.
You can download my drawing shown as belowby click here.
Now, you’ll need two pieces of Plywood (3mm 40cm*60cm), and cut the plywood according by the drawing that you have already downloaded.
Then you should connect the Grove Modules to the plywood using screws and nuts and affix the pendulum supports.
Then, connectGrove Modules to the plywood using screws and nuts.
At last, connect
Grove Modules to baseshiled according to the chart below and adjust the laser
emitter to let the laser to shoot on the light sensor.
Congratulations, you have already completedthe most of the work.
Through repeated testing, we can see that the formula is correct, And T1:T2:T3 = 3:4:5, the cycle of the pendulum ball is all about the length, not the quality.
This project is made as an Open Source Project. It's a starting point. Let your creativity go wild with the mechanical, electrical and software design. Make the demo your own. Decorate it. Improve the work. No matter what, write a recipe about it.
To share and progress together.