Chapter 3 LED Bar

We have learned how to control a LED blinking, next we will learn how to control a number of LEDs.

Project 3.1 Flowing Light

In this project, we use a number of LEDs to make a flowing light.

Component List

  • ESP32-S3-WROOM x1

  • GPIO Extension Board x1

  • 830 Tie-Points Breadboard x1

  • Resistor 220Ω x10

  • Jumper Wire x10

  • LED Bar Graph x1

Connect

../_images/31.png

Code

This project is designed to make a flowing water lamp. Which are these actions: First turn LED #1 ON, then turn it OFF. Then turn LED #2 ON, and then turn it OFF… and repeat the same to all 10 LEDs until the last LED is turns OFF. This process is repeated to achieve the “movements” of flowing water.

03.1_FlowingLight

Move the program folder “Basic_Starter_Kit_for_ESP32_S3/Python/Python_Co des” to disk(D) in advance with the path of “D:/Micropython_Codes”.

Open “Thonny”，click “This computer” >> “D:” >> “Micropython_Codes” >> “03.1_Flo wingLight” and double click “FlowingLight.py”.

../_images/3.12.png

Click “Run current script” shown in the box above, LED Bar Graph will light up from left to right and then back from right to left.

../_images/3.13.png

The following is the program code:

import time
from machine import Pin

pins=[21,47,48,38,39,40,41,42,2,1]

def showled():
    length=len(pins)
    for i in range(0,length):
        led=Pin(pins[i],Pin.OUT)
        led.value(1)
        time.sleep_ms(100)
        led.value(0)
    for i in range(0,length):
        led=Pin(pins[(length-i-1)],Pin.OUT)
        led.value(1)
        time.sleep_ms(100)
        led.value(0)

while True:
    showled()