Humidity sensor with led alarm | Arduino project

This page contains Arduino Humidity sensor with led alarm source code. This project is good for someone who wants to make a humidity meter or hygrometer with led alarm if humidity and temperature over a threshold. It's easy to make and doesn't require an external power supply, just use power from an Arduino UNO R3 board (USB power compatible with this project).

Electronic components list:
1 x Arduino Uno R3
1x 20 x4 I2C LCD display
1 x AM 2320 humidity/temp sensor
1 x 5 mm led ( 2 x if you plan to use led for pin 13 instead built-in led)
1 x 1000 ohms resistor ( 2 x if you plan to use led for pin 13 instead built-in led)
Any USB power adapter, 500 mA current at least.

Here is the Arduino code:
AM 2320 library https://github.com/hibikiledo/AM2320
LCD display i2c library https://github.com/fdebrabander/Arduino-LiquidCrystal-I2C-library


#include <Wire.h>
#include <AM2320.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x3F, 20, 4);
AM2320 th;
int led2 = 12;
vo…

usb power automatic night light.

Hello, today I'm going to show you how to build easy usb power automatic night light with easy to understand wiring diagram in this video.
The circuit consume just .24 mah per hour and can add up to 5 or more leds (five leds are recommend or just change some resistor value and attach heatsink to output transistor).
As you can see in this video that I used 4  rechargeable battery and got 4.8 volts, so you can use usb charger as power source too.

List of component
2 BD 139 transistors or equivalent transistor
1 100 ohms resistor
1 1000 ohm resistor
1 20,000 ohm resistor
1 photo resistor
1-5 LEDs (the more led the more power consume if you use batteries power souce)

wiring diagram:



Test circuit video.


Hope you like it.

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