Moisture Meter

The Moisture Meter measures moisture levels as detected through either a Watermark Soil Moisture Sensor or a Leaf Wetness Sensor. It works by measuring the resistance of these sensors, which decrease as moisture levels go up.

To set up the Moisture Meter, you will need to connect all 5 terminals of the screw terminal. Two of the screw terminals connect the Gypsum Soil Sensor or the Leaf Wetness Sensor; see below for installation instructions for these devices. To connect the Moisture Meter to your 1-Wire network, simply connect the 1-Wire data line to the screw terminal marked DQ, and connect the 1-Wire ground line to the screw terminal marked GND. This device also requires 9-24 volts of external power, which should be connected to the screw terminal marked +12v and GND. For more information, please see our general discussion of Connecting Devices to the 1-Wire Network.

Since your Moisture Meter will most likely be installed in a humid environment, you should take precautions to protect it. The board should be mounted inside a weather-tight enclosure if possible. We recommend coating the device with a spray coating, which is available through us when you purchase an assembled device. If you coat the board yourself, use liquid electrical tape or spray varnish. Apply the coating after the connections have been made, and be sure to coat the terminals well. The Moisture Meter does not have RJ45 connectors, as they may not hold up as well in outdoor exposed conditions.

The Moisture Meter is a relatively new 1-Wire device. It will work with any software that supports a DS2760. If you have favorite software, you should check whether the device is supported. An increasing number of software vendors are including support for this device.

Watermark Soil Moisture Sensor:
The Moisture Meter can be very simply connected to the Watermark Soil Moisture Sensor by directly connecting the built-in wires of the soil sensor to the screw terminals labeled SENSOR. You can extend the wires using twin-lead, CAT-5 or other twisted-pair wire. The Watermark Soil Moisture Sensor should last approximately 5 years before needing to be replaced.

Watermark Soil Moisture Sensors work by detecting changes in the resistance of the gypsum block as it absorbs moisture from the surrounding soil. The soil sensor should be installed in your garden or yard, according to the root zones of the plants you intend to grow. Ideally, two sensors would be placed at different depths, one in the center of the root zone and the other near the bottom of that zone. This enables you to ensure deep watering, and to re-water when the soil starts to dry out in the middle of the root zone. A typical depth for a vegetable garden might be at 12” – 24” (30cm-60cm). For large yards or gardens, more than one monitoring station may be desirable, especially if the sunlight exposure, soil, or drainage is very different across the area. To install, pre-soak the soil sensor in water for at least an hour. Dig a hole for the sensor to the desired depth, reserving the removed soil. Soak the hole, and insert the soil sensor. Make a slurry out of the reserved soil, and backfill the hole with this slurry.

Leaf Wetness Sensor:
The Leaf Wetness Sensor is also easily connected to the Moisture Meter. It does not come with attached wire -- you will need to solder the desired length of speaker wire (or other wire) to the two connector holes, and then connect the other end of the wire to the Moisture Meter screw terminals labeled SENSOR. We do not recommend using wires longer than about 10’ (3m), as the long wire length may skew the readings of your moisture meter.

The Leaf Wetness Sensors work by detecting changes in the sensor’s resistance as moisture bridges across the traces. The Leaf Wetness Sensor should be periodically wiped clean to remove contaminants and prolong its life. To mount the Leaf Wetness Sensor, you can use the screw hole provided. The sensor should be mounted horizontally or at an angle rather than vertically. The appropriate mounting location should be selected depending on whether you desire to measure moisture from rain, dew, fog, etc.