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
LCD display i2c library

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

DIY toggle touch sensitive switch

Hello everyone, today I'm going to show you how to make a touch sensitive switch, the switch makes you control light,motor just by touch the switch. The switch is very long life and safe to operate even your hand wet because you can put the touch sensor behind any plastic plate and make a touch sensitive light switch or you even can put the circuit in a lamp and make a touch lamp.

This circuit uses CD4013BE d flip-flop IC . When you touch the touch sensor( The red module on the above picture) The sensor send output high to CD4013BE pin3 and make CD4013BE pin 1 change state to on or off once.
However, CD4013BE output current not high enough for a relay to operate(yellow-black box on the above picture) so you need a PNP transistor(BD140) to amplify current for a relay.
You can remove R4 and LED if you don't need light indicator in your project.
This circuit uses 5 volts DC to operate so you need a transformer and it cause your overall circuit big but you can buy a tiny 220/110 v AC to 5 volts DC transformer to eliminate the problem, the transformer cost around 3$. I use a transformer because I want to make simple and safe circuit and the transformer life expect is 100,000 hours or 11 years!!!
Hi-Link 100 - 240 AC to 5 volts DC switching transformer.

Electronic components list:

IC1 CD4013BE
Transistor BD140 PNP type
5 volts relay
TTP223b touch sensor module
R1,R3,R4 = 2 Kilo-ohms
R2 value is 100 kilo-ohms
LED = warm white led but you can change it to another color as you wish

Circuit test video.

Enjoy hobby world!!!


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