Rain Detector Module & Relay Interface Kit
Control the relay with moisture

This listing is for a small moisture detection board and a relay board interface board set.  The resistance of the two on board leads of the moisture detection board varies depending on how much moisture is touching it.  The relay board interfaces directly with the moisture detection board.  If you watch the above video, you get a full demonstration of how it works.  The sensor board is essentially a variable resistor.  If a ton of moisture is touching the board, you can get resistances of down to 100k ohms or less.  If there is no moisture, or water touching the sensor board, the resistance will be more than 2M ohms.  The relay board has a comparator circuit on it with adjustable sensitivity adjustment via an on board variable resistor.  You can tune the relay board to react to high moisture or low moisture.  The relay board has two leads that connect directly to the comparator board (as seen in the video).  The relay board has four interface pins in total.  Two of them are used to interface directly with the moisture detection board.  The pin labelled "VCC" is where you connect your supply voltage of no more than 5v.  The pin labelled "GND" is your input supply ground pin.  By default, when you apply 5v to the relay board, the relay is turned off.  After you tune your board for sensitivity, when enough moisture hits the moisture detection board, the relay will turn on and stay on up until the sensor board is dry.  Seriously, watch the above video to see how it all works.  This listing comes with a moisture detection board, a relay board, and four connection cables.  The relay has a three pin output terminal block.  They are not labelled properly, so be sure to look for the pin-out in the above video.  There are three output terminals for the on board SPDT relay: NC (Normally Closed), CO (Common), NO (Normally Open).  When the relay is off, the common pin is connected to the normally closed pin.  When the relay is activated, the common pin disconnects from the normally closed pin, and connects to the normally open pin.    If after reading this and after watching the above video you have any questions, please do not hesitate to ask =)  


Specifications:
Sensor Board Length: 53mm
Sensor Board Width: 40mm
Sensor Board Height: 77mm (With leads)
Relay Board Length: 52mm (With leads)
Relay Board Width: 25mm
Relay Board Height: 18mm
Relay Board Supply Voltage: 4.5v-5v