How to Build a Rain Sensor

What You'll Need
6-volt battery
Alligator clip wires
Wire cutters
Wire strippers
Duct tape
Piece of wood
Piece of plastic sheet
Sensor pad

Although it is easy to look out of a window to determine whether rain is falling, machines do not have this luxury and could benefit from a rain sensor. A sensor can prove to be a helpful addition to a range of machines to detect when certain mechanisms should be put into operation. Following the necessary steps to build a sensor will ensure that you have the means to make your appliances work more efficiently.

Step 1 – Plan

Begin the process of building a rain sensor by deciding on the manner in which you want it to indicate that it detects rain. This will usually be dependent on the purpose of the sensor as this will help determine which is more beneficial. You can build a sensor that indicates rainfall with light or sound, or using a switch to operate another action.

Step 2 – Gather and Prepare Materials 

The next step is to gather all the materials and equipment needed to build the rain sensor. In order to ensure that you get the correct amount of materials, you should begin by measuring the item that you will be adding the sensor to. If you intend the sensor to stand-alone, ensure the dimensions are such that the result will be an appropriate size. Measure twice before cutting and remember that you will need to strip at least half an inch off the end of the insulated wire.

Step 3 – Assemble Components

Cover the piece of wood with the plastic sheeting to protect it and prevent water from soaking into it, secure it beneath the base with some duct tape. The sensor should be centrally placed on top on this and fixed in place with tacks. Depending on the type of sensor obtained, you may need to attach wires to the body of the rain sensor or directly to the sensor pads. There should be a narrow strip remaining between the two sensing components which will be connected by the water when rain falls on it. Attach the wires using the most appropriate method, such as fixed in place with tacks or staples if the alligator clips do not fit. One of the wires will lead to the indicator to operate the sensor and the other will need to lead to the battery. Another wire must be attached to the other side of the indicator.

Step 4 – Complete Circuit

Once the rest of the components for the rain sensor are assembled, you will be in a position to connect it to the power source. Attach the alligator clips on the end of the wires to the battery so that the entire circuit is complete. Test whether it works by laying a paperclip between the two sensors or by dripping some water onto the sensor. After ensuring that it works, the wires can be covered with plastic sheeting so that over the sensor is exposed.