Rain Detector Alarm (Alarm Pendeteksi Air Hujan)

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.

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Rain Detector Circuit (Detektor Hujan)

Skema Rangkaian Detektor Hujan

Rangkaian ini sangat berguna untuk memberitahu kita bahwa hujan akan segera terjadi. Apalagi saat kita sedang menjemur pakaian. cara kerjanya cukup sederhana saat kita sedang nonton TV atau bahkan tertidur jika ada hujan turun maka secara otomatis rangkaian akan membunyikan alarm sehingga kita dapat segera memasukkan jemuran ke dalam rumah (asal kita terbangun saat mendengarnya.....).

Prinsip kerja rangkaian cukup sederhana. supaya lebih memahami prinsip kejanya coba lihat gambar rangkaian berikut.





angkaian ini akan menggunakan IC555 yaitu ic timer. pada aplikasi ini kita gunakan sebagai pembangkit sinyal kotak dengan frekuensi 1 KHz. Pada titik A-B kita hubungkan ke sensor air yang kita buat sendiri. Jika titik AB terhubung maka IC 555 akan mengahasilkan sinyal kotak pada kaki no 3 sehingga speaker akan berbunyi.

Untuk membuat sensor air sebenarnya terserah ukurannya yang jelas semakin lebar/besar semakin bagus karena kemungkinan tetes air hujan menganai papan semakin besar. dan jangan lupa meletakkan sensor air di luar rumah suapaya saat terkena air hujan sensor mejadi aktif. untuk aluminium foil kita bisa menggunakan bekas pembungkus makanan ringan.

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Rangkaian Pendeteksi Air Hujan sederhana

circuit of rain detector uses a sensor made of a small piece of etched PC board and a simple SCR circuit to detect rain and sound a buzzer. The SCR could also be used to activate a relay, turn on a lamp, or send a signal to a security system.

Circuit of rain detector

Component list of rain detector

• R1 1K 1/4 W Resistor
• R2 680 Ohm 1/4 W Resistor
• D1 1N4001 Silicon Diode
• BZ1 12V Buzzer
• S1 SPST Switch
• SCR1 C106B1 SCR 106CY
• SENSOR

The sensor is a small piece of PC board etched to the pattern showen in the schematic. The traces should be very close to each other, but never touching. A large spiral pattern would also work.

Make sure to use a loud buzzer.

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