This project is inspired by a project -- a revolving LEDs(led lights up from LED1 to LED10 then go back from 10 to 1).

---from Michael McRoberts' book "Beginning Arduino".

When I was doing this project suddenly I realized that maybe I could revise the code to make the LEDs light up like a free -fall ball bouncing on the ground, so I tried and made it.

Step 1: 1.parts and Connection

Very simple wiring work and parts:

1. 1 x bread board

2. 1 x Arduino UNO (or other versions)

3. 10 x 5mm LED

4. 10 x 100 Omega Resistors

5. some wires

connects leds with arduino as pictures show, use Arduino pin4~pin13 as output pins to light up 10 leds, do not forget wire the ground together and wire to Arduino ground.(ignores the arduino micro on the picture 1), then the rest is all about coding and debugging.

Step 2: The Code and the Philosophy Behind the Project

( the upload videos are green and colorful version of gravity led, youtube doesn't work in China ,sorry )

In this small project which interest me is about the philosophy(might be wrong):" Our universe is a enormous computer which is running a program called the law of nature." then we could use a smaller computer( even as small as Arduino) to run a similar program to imitate the law of nature like a tiny universe does.

The code is about how to transfer the formula: H(height)= 1/2 g t^2 into arduino code if you have interest pls check the attached document. It is physics taught in grade 7th in China but I spent 2 days to debug and adjust the code , in order to find out the better equation of formula I calculated on paper about 10 pages for beating around the bush.(My high school teacher will be touched if he knew that after 10 years from graduation.)

Just by Led and arduino we could create almost infinite tricks.As a beginner of arduino , my code is primitive ,(actually I still confuse that why denominator is zero is ok in the code ) if you have a better solution, it will be very thankful to let me know.