This project involves creating a rain alarm system that automatically closes plates when rain is detected to prevent materials from getting wet. The system uses a rain sensor connected to a 555 timer chip to trigger a buzzer when rain is detected. It is powered by a 9V battery and includes common electronic components like resistors, capacitors, and an NPN transistor. The project is designed to be low-cost and useful for protecting materials in homes and small businesses from rain damage and the negative effects of wet conditions.

1. RAIN ALARM PROJECT
1
Chapter No:-1
ABSTRACT
This project is entitled as “RAIN ALARM WITH CLOSING FACILITY” used in home and cottage
industries. The main purpose of this project is to prevent the materials from rain. Using this project we can
avoid the mental stress. These are special types of wipers that turn on automatically when it begins to rain
and turn off when the rain stops. This is based on the versatile, multipurpose timer chip 555. The timer 555
is used in the monostable mode in the project. The sensor is connected between the trigger pin ground. The
closing plates are connected with the relay when the rain starts the sensor will ON and plate closed. This
project is usefull in home and cottage industries.

2. RAIN ALARM PROJECT
2
Chapter No:-2
INTRODUCTION
Rain Alarm Project is a simple but very useful project that detects Rain (Rain Water) and automatically
triggers an alarm or buzzer. Water is a basic need in every one’s life. Saving water and proper usage of
water is very important. Here is an easy project which will give the alarm when there is rain, so that we can
make some actions for rain water harvesting and also save the rain water for using it later. With the help of
saving this rain water through rain water harvesting, we can increase the levels of underground water by
using underwater recharge technique. Rain water detector will detect the rain and make an alert; rain water
detector is used in the reliable circuit of rain water detector which can be constructed at low cost irrigation
field, home automation, communication, automobiles etc. Here is the simple and irrigation field, home
automation, communication, automobiles etc.
Components
1. Rain sensor
2. 555 Timer IC
3. NPN Transistor BC547
4. Resistors (470, 100k and 1k ohm)
5. Capacitor (10uf)
6. Buzzer
7. Battery 9v
Components For PCB Design:
1. Laser printer
2. Electric Iron
3. 4”*6 sticker
4. Liquid of ferric chloride(Cl3Fe)
5. Mini drill machine
6. Liquid rosin

3. RAIN ALARM PROJECT
3
Chapter No:-3
CIRCUIT DIAGRAM

4. RAIN ALARM PROJECT
4
Rain Alarm Project Block Diagram
The block diagram of the Rain Alarm Project is shown in the following image. The three main components
of the project are the Rain Water Sensor, 555 Timer IC and Buzzer.

5. RAIN ALARM PROJECT
5
When the Rain Water Sensor detects the Rain, it sends a signal to the 555 Timer. The 555 Timer IC, which
is configured in its Astable Mode, will then activate the Buzzer.
Rain Water Sensor
The Rain Water Sensor used in this project is shown in the image below. It is a simple sensor and it is an
easy to use tool for detecting rain. It can act as a simple switch, where the switch is normally open and when
there is rain, the switch closes.

6. RAIN ALARM PROJECT
6
Even though Rain Water sensor is the main component in the circuit. We need not to go and buy in the
market or online. We can do it ourselves just by taking the piece of Bakelite or Mica board and aluminium
wire.
Bakelite or Mica board should be made completely flat and aluminium wire should be pasted on the flat
board as shown in the figure below. Care should be taken that there should be no spaces between the wire
and board.
When the rain water sensor is completed, it should get connected to the circuit and voltage should be passed
through the wires.

7. RAIN ALARM PROJECT
7
If
there is no rain, the resistance between the contacts will be very high as there will be no conduction between
the wires in the sensor.
If there is rain, the water drops will fall on the rain sensor, which will form a conductive path between the
wires and it also decreases the resistance between the contacts.
How a Rain Sensor Works:
There are three ways in which a rain sensor works. The first is by using a collection cup where rainwater is
collected and weighed. The weight of the rain water in the collection cup will then break the electrical
connection to the pump or sprinkler valves of your lawn irrigation system. The second way is a variation of
the first where instead of weighing the amount of water in the collection cup, an electrode is used to measure
the amount of rainwater. The third way is by using an expansion disc made of cork. When enough rain hits
the cork, it expands and triggers the break mechanism of the rain sensor preventing electricity from running
into your lawn irrigation system.

8. RAIN ALARM PROJECT
8
Chapter No:-4
WORKING PRINCIPLE AND OPERATION
It is a very simple rain alarm circuit which is designed using mainly a transistor, water sensor and a 555
timer IC. Whenever there is a rain, rain drops falls on the rain sensor, and as you can see in the diagram of
rain sensor, water on rain sensor would short the Point A and B. As soon as Point A and B become short, a
positive voltage would get applied on the base of Transistor Q1, through the resistance R4. Because of the
voltage at the base, transistor becomes ON (initially it was in OFF state), and current started flowing form
collector to emitter.
Now Reset PIN 4 of the 555 Timer, gets a positive voltage and 555 timer IC becomes ON and Buzzer starts
beeping. Here we should note that initially there was no positive voltage at Reset PIN 4 of 555 IC, as it was
connected to the ground through resistance R5 (4.7k) and 555 IC only works when Reset pin gets positive
voltage.
Here we can see that 555 Timer IC has been configured in Astable mode so that Buzzer generate a
oscillating sound (means periodically on and off). This oscillation frequency can be controlled by changing
the value of resistor R2 and/or capacitor C1. Pin 5 control Pin, should be connected to ground through a
.01uf capacitor. Resistor R3 and R4 has been used to control the transistor’s collector and base current
respectively.
Rain sensor should be kept at 30-40 degree from the ground, so that water cannot stay on it, for the long
time, this will prevent the alarm to going on for a long time.
How a Rain Sensor Works:
A rain sensor is an automated device that shuts off your lawn irrigation system every time it rains. It is a
relatively cheap device that can save up to 45 percent of your water bills, help protect the environment and
conserve water. A rain sensor is mounted outdoors away from trees and roof over hangs so that it can collect
rainwater without obstruction. A rain sensor can either be wired or wirelessly attached into a lawn irrigation
system

9. RAIN ALARM PROJECT
9
Chapter No:-5
SPECIFICATION
Sr.n
o
Symbol Name of
component
Power
rating
1.
Resister R=10k ohm,
1w, 5%
2.
Resister Resistance
(Ohms) 68K
Tolerance ±2%
Power Per
Element
100mW
3.
Resister 270 ohm 2w
5%
4,.
capacitor Capacitance
(uF): 10uF
Voltage: 35V
Lead/Terminal
Type: Radial
Number
Leads/Terminal
s: 2
Temperature: 8
5�
5.
NPN Transistor BC547
Transistor (bjt)
- Single
Discrete
Semiconductor
Product 100mA
45V 625mW
NPN

10. RAIN ALARM PROJECT
10
6. 555 Timer IC
Dual 8-Channel
CMOS
Analogue
Multiplexer,
based on type
HI507A

11. RAIN ALARM PROJECT
11
7. BUZZER
Positive:
Identified by
(+) symbol or
longer terminal
lead. Can be
powered by 6V
DC
Negetive:
Identified by
short terminal
lead. Typically
connected to
the ground of
the circuit
8. Rain sensor
The module is
based on the
LM393 op
amp.

12. RAIN ALARM PROJECT
12
9. battery
9v power
supply

13. RAIN ALARM PROJECT
13
Chapter No:-6
COST ESTIMATION
Sr. no Name Cost Quantity
1 Printed circuit board 105 1
2 battery 20 1
3 transistor 70 1
4 Integrated circuit 40 1
5 capacitor 20 1
6 Resister 7 1
7 Rain sensor 50 1
Total Cost 312

14. RAIN ALARM PROJECT
14
Chapter No:-7
ADVANTAGES
1. Conserve Water
2. Prevent Disease Damage and Nutrient Loss:.
3. Save Money on Fertilizer:
4. Increase the Life-span of your Irrigation System:
5. Prevent Groundwater and Waterways Pollution:
APPLICATIONS
1. In the irrigation, it will detect the rain and immediately alert the farmer.
2. In automobiles, when the rain detector detects the rain it will immediately active the wipers and inform
the driver.
3. In communications, it will boost the power of the antenna and increase the signal strength to send or
receive the signals.
4. In normal house hold
5. This can also be used if there is a chemical rain also.

15. RAIN ALARM PROJECT
15
CONCLUSION
The entitle of is project “RAIN ALARM WITH CLOSING FACILITY” project is essential for fertilizer and
cottage industries. The main purpose the project is to avoid mental stress and to the prevent material from
rain. This is project can construct easily using simple electronics component

16. RAIN ALARM PROJECT
16
REFERENCES
M.D. Singh, K.B. Khanchandani, Power Electronics, Second Edition, Tata McGraw-Hill
https://circuitdigest.com/electronic-circuits/rain-alarm-project
Make: Electrónica (Spanish Edition) Kindle Edition by Charles Platt (Author)