•  
  •  

Rain Alarm

This circuit gives out an alarm when its sensor is wetted by water.
A 555 astable multivibrator is used here which gives a tone of about 1kHz upon detecting water.
The sensor when wetted by water completes the circuit and makes the 555 oscillate at about 1kHz.
The sensor is also shown in the circuit diagram.

It has to placed making an angle of about 30 – 45 degrees to the ground. This makes the rain water to flow through it to the ground and prevents the alarm from going on due to the stored water on the sensor.

The metal used to make the sensor has to be aluminium and not copper. This is because copper forms a blue oxide on its layer on prolonged exposure to moisture and has to be cleaned regularly.
The aluminium foils may be secured to the wooden / plastic board via epoxy adhesive or small screws.
The contact X and Y from the sensor may be obtained by small crocodile clips or you may use screws.

If there are any problems please contact webmaster@electronic-circuits-diagrams.com

Please share & like


Police Stun Gun SGT928-700BV Maximum Power Rechargeable With Ear-Piercing Alarm picture

Police Stun Gun SGT928-700BV Maximum Power Rechargeable With Ear-Piercing Alarm

$15.95



Simplex 2901-9833 Red Audible Horn Signal Device Fire Alarm 87 Db picture

Simplex 2901-9833 Red Audible Horn Signal Device Fire Alarm 87 Db

$38.00



POLICE Stun Gun TW10 700 BV Heavy Duty Rechargeable LED Flashlight Siren Alarm picture

POLICE Stun Gun TW10 700 BV Heavy Duty Rechargeable LED Flashlight Siren Alarm

$17.99



2 Pieces Alarm Buzzer DC 12V 75dB Mini  Alarm Buzzers Constant Tone US/SH picture

2 Pieces Alarm Buzzer DC 12V 75dB Mini Alarm Buzzers Constant Tone US/SH

$7.98



Wheelock 7002T-24 Fire Alarm Horn Strobe picture

Wheelock 7002T-24 Fire Alarm Horn Strobe

$22.00



building fire alarm Cerberus Pyrotronics picture

building fire alarm Cerberus Pyrotronics

$25.00



Simplex 4251-20 Fire Alarm Pull Station Front with 2099-9795 Module (For Parts) picture

Simplex 4251-20 Fire Alarm Pull Station Front with 2099-9795 Module (For Parts)

$18.00



GE Edwards Signaling 270-SPO Fire Alarm Pull Station   (BOX A16) picture

GE Edwards Signaling 270-SPO Fire Alarm Pull Station (BOX A16)

$9.99



Universal 12000GS Magnet Golf Magnet Strong 12000GS Remover Universal Alarm Tool picture

Universal 12000GS Magnet Golf Magnet Strong 12000GS Remover Universal Alarm Tool

$26.99



Fake Solar Auto Car Alarm Led Light Security System Warning Theft Flash Blinking picture

Fake Solar Auto Car Alarm Led Light Security System Warning Theft Flash Blinking

$8.09