18-09-2017, 08:25 PM
: Hi am sundar i would like to get details on pdf of rain alarm system ..My friend Justin said pdf of rain alarm system will be available here and now i am living at ......... and i last studied in the college/school ......... and now am doing ....i need help on ......et
Posts: 14,118
Threads: 61
Joined: Oct 2014
This circuit gives an alarm when its sensor is moistened by water.
Here an astable 555 multivibrator is used which gives a pitch of about 1 kHz when detecting water.
The sensor when dampened by water completes the circuit and causes the 555 to oscillate at approximately 1kHz.
The sensor is also shown in the circuit diagram.
It has to be placed at an angle of about 30 - 45 degrees from the ground. This causes rainwater to flow through it to the ground and prevents the alarm from being triggered by the water stored in the sensor.
The metal used to make the sensor has to be aluminum and not copper. This is because copper forms a blue oxide in its layer on prolonged exposure to moisture and has to be cleaned regularly.
The aluminum foils can be fixed to the wood / plastic plate by means of epoxy adhesive or small screws.
The X and Y contact of the sensor can be obtained with small crocodile clips or you can use screws.