Rain Detector

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This circuit 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.


This is the schematic of the Rain Detector


Total Qty.
R111K 1/4 W Resistor
R21680 Ohm 1/4 W Resistor
D111N4001 Silicon Diode
BZ1112V Buzzer
S11SPST Switch
SCR11C106B1 SCR106CY
SENSOR1See Notes
MISC1Board, Wire, Case, PC Board (For Sensor)


  1. 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.
  2. Make sure to use a loud buzzer.

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Rain Detector
Friday, March 20, 2015 2:45:17 PM
im trying to make a 6 volt rain sensor that will move a 6 volt motor back and forth
Rain Detector
Wednesday, March 19, 2014 1:17:31 PM
Can v extend this circuit for automatic wiper.if so plz send me the extended circuit
Rain Detector
Thursday, February 16, 2012 10:09:26 PM
change the scr with a bjt NPN transistor
Rain Detector
Wednesday, December 21, 2011 10:16:39 AM
Why doesn't OFF when it drys?. Very simple: change The DC supply for an AC supply; the SCR turns OFF during the power supply's negative cycle . Additionally, you can change the SCR for a TRIAC.
Rain Detector
Tuesday, December 13, 2011 9:37:09 PM
If it detects rain, and when it drys it still thinks there's rain probably you could put 1N4148 instead of 1N4001 because 1N4148 is a fast recovery diode... maybe...
Rain Detector
Sunday, November 06, 2011 3:20:17 AM
hey. Is this parts also available in south africa? Lol.. sorry but I would like to know
Rain Detector
Saturday, March 05, 2011 12:01:38 AM
SIR, can you explain the function of each part of the circuit, especially the diode and the resistor.
ubed ullah khan lohani
Rain Detector (to stop the buzzer)
Monday, August 16, 2010 10:02:46 PM
to stop the buzzer you have to replace the SCR with a BJT in darlington pair arrangement... and also use 10k resistance as R1 connected with gate.. and the collector of transistor with the buzzer's leg. and emitter =>ground.........BJT 547 will be sufficient for that.
Rain Detector
Sunday, July 11, 2010 4:17:01 AM
i have maid one, its perfect! i just follow the schematic and it works.
Rain Detector
Monday, June 21, 2010 6:19:44 AM
Is it really not switching off when the sensor is dry?
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