Riverina based company Hussat Pty Ltd has been using the T15105 and R15105 data modules to transfer soil moisture readings over distances up to 12 km.

Using the design skills of Elsema engineers the T15105 transmitter module was combined with a microcontroller and associated electronics and firmware to build the wireless soil moisture logger (Plate 1 & 2). The logger measures the resistance of up to eight Watermark™ soil moisture sensors (www.irrometer.com) and sends the readings at 1200 baud via the ANT151M antenna to a R15105 receiver module at the base-station (Plate 3). A microcontroller in the base-station reads the data from the receiver and passes it to the internet via a GPSR modem giving soil moisture measurements in real-time, as shown in the live examples on the homepage  www.hussat.com.au.  The base-station also uses the ANT151M antenna which is elevated 4 metres above ground.

“We have been using Elsema’s 151MHz modules since they were first produced and have been obtaining reliable communications over 3 km range, however we are delighted with the new R15105 module (Release date December 2008) because it is super sensitive and has increased our range to 12 km”, said Hussat engineer Paul Hutchinson. “We recently commissioned a field site in Yanco, NSW using the new R15105 in our base-station and to our surprise data was coming from a walnut farm on the other side of Leeton, NSW a distance of 12 km away”.  “Within the radio path is a township, countless trees and buildings…amazing”

Plate 2.  The wireless soil moisture logger deployed in a peach orchard in Lake Wyangan.

 Plate 1.  The wireless soil moisture logger.  Inside is a T15105 transmitter and the antenna is an ANT151M. The logger is power by AA batteries and has a service life of 2 years.

Plate 3.  A base-station which includes a R15105 receiver, ANT151M antenna, microcontroller, GPRS modem and power.