Rain Alarm Project
Rain Alarm Project is a simple but very useful project that detects Rain (Rain Water) and automatically triggers an alarm or buzzer.![rain alarm rain alarm setup](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTFIQMmjrVcfX4Us6aYciGkgGAaRVU88aTXkWym8vz-Y6TU6Xu5fqZrRNd1VG-t3L2Ylqmy0qNnvdM2VSXBJfCMzCnp7dyE4SIwr3pAdllJ9xjJI46L_QFsX5KOkp8-As40WthL71fycLa/w400-h225/lbm4.rainalarm.jpg)
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 irrigation
field, home automation, communication, automobiles etc. Here is the simple and
reliable circuit of rain water detector which can be constructed at low cost.
![rain sensor rain alarm sensor](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiK1g3UZuenQgEOB3UwD6OM53QCENNxVz8J1S09L8FrBr6SWpihdpVATBEmyyz12345q-9I-DJtQopHBC6_KPTv1xCnbuh9FJLWC5psEeeHPOggyrVDr2Y5ts2HU7prZNmnYmAxdwGakJUf/w200-h164/lbm4.rainsensor.jpg)
This Rain Sensor is connected to the main circuit, so that
the voltage should pass through this rain sensor’s wires. In normal conditions
(if there is no rain), the resistance between the aluminum wires will be very
high as a result there is no conduction between the wires. When it rains, water
drops falls on the rain sensor, which decreases the
resistance between the wires. As a result wires on the sensor sheet
starts conducting and trigger the NE555 timer IC through the transistor circuitry.
![block diagram for working of rain alarm sensor](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjCCcWh4CzjcAfRg9-BO_mbyerR3OlgON2jd8ggbm4JdA68jefshfNlUVGcftL6nSWDRDd0Na0SzI11SuFzFoJRifBb55FnbnX9yT050PSNu0JR1CwTWoxvuU_7ET0izCDM-ExNxdG-vNvJ/w320-h70/rai+alarm+sensor.png)
Components Required
- 1 x Small Rain Sensor
- 1 x 555 Timer IC
- 1 x BC548 NPN Transistor
- 2 x 2N2222 NPN Transistor
- 1 x Bright White LED
- 1x 1N4007 PN Junction Diode
- 1 x 220 KΩ Resistor (1/4 Watt)
- 1 x 330 Ω Resistor (1/4 Watt)
- 1 x 10 KΩ Resistor (1/4 Watt)
- 1 x 470 KΩ Resistor (1/4 Watt)
- 2 x 3.3 KΩ Resistor (1/4 Watt)
- 1 x 68 KΩ Resistor (1/4 Watt)
- 1 x 22 µF Capacitor (Polarized)
- 2 x 100 µF Capacitor (Polarized)
- 1 x 10nF Ceramic Capacitor (Code – 103)
- 1 x 100pF Ceramic Capacitor (Code – 101)
- 1 x Buzzer (or Speaker – 8Ω)
- Connecting Wires
- Breadboard
- 12V Power Supply
Working Principle
This is a simple project. Any
electronics student or hobbyist can make this project without much effort. When there is
rain, the Rain Sensor's wires start
conducting. Since it is connected to the Rain Alarm’s circuit, the transistor Q1 will get turned ON
and LED D1 starts glowing. At the same time Q2 will also be turned ON. When Q2
reaches its saturation state, the capacitor C1 will act as a short and make the
transistor Q3 to be conducting. The RESET pin of 555 Timer IC is connected to
the emitter of Q3. When Q3 reaches its saturation mode, it will assert the
RESET pin of Timer IC to High or Positive. As a result, it will generate
a pulse in the OUT pin 3 of 555 Timer and make the speaker to produce alarm.
The 555 Timer IC is configured to operate in astable mode. A capacitor C4
is connected between the speaker and OUT pin3 of timer IC. This capacitor
blocks the DC and unwanted components to the speaker.Depending on the
time constant RC (R4, C1), after some time, the transistor Q3 will get in to
cut off. The time period for the speaker to make sound is depends on the
R4 and C1 values.
Circuit Diagram
![rain alarm circuit rain alarm circuit diagram](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjXjTF7yc-jtf0JmUKS5l2m1pmPz9jjUcPXKaaeePK8zrbVxdr44mxTXwB8IldMkULJxj1H5fudLCYzNiUlVWukYomJorl-5Z85j2Pm1dBgqCb7tdT211bZgCanHQDcIsTLRiasqYplennH/w640-h302/lbm4.rain.circuit.png)
- Rain senor should be kept in the open place at 30 to 40 degrees from the ground. As a result, rain water will not be present on the sensor for long time.
- This circuit will automatically switch of the alarm after sometime and LED will glow continuously until the rain stops.
About Rain 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.
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.
![rain alarm interal architecture](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_VbCXh9xJ_-SeY6V1rkA8Uq3HnJ1BJtMytWg1IFBkc_YxTySs89zXL_fsEL6_KHPFAhaumKysRx5rIFdnYummSi_Aln0FDUjEdTTa8QtdjVCrVRUIgay_ZBP3zSvJbFu7_GVYCUvEl5YO/w320-h281/lbm4.rain+sensor+c.jpg)
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.
As a result, the wires on the
sensor board will conduct and trigger the NE555 timer through the transistors
circuitry. Once NE555 is triggered, it will make the output pin high and which
will make the buzzer to make alarm.
Application:
- In the irrigation, it will detect the rain and immediately alert the farmer.
- In automobiles, when the rain detector detects the rain it will immediately active the wipers and inform the driver.
- In communications, it will boost the power of the antenna and increase the signal strength to send or receive the signals.
- In normal house hold, with the help of rain water detector we can automatically save the rain water. (This can be done only when home automation is done and there is proper equipment to save the rain water. In this, rain water detector will detect the rain and helps to switch ON the equipment which will automatically save rain water for different purposes).
- This can also be used if there is a chemical rain also. This is very common in industrial areas.
good job keep on going
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