The Linobjec temperature sensor is being used to monitor temperature in grain silos


The Irish grain yield can regularly be stored for up to a year after harvest before processing. During this period the grain can deteriorate in the store due to natural decay and insect infestations. This deterioration is hastened by the initial temperature being too high. Once infestation starts, the temperature continues to rise ever more quickly. The higher the temperature rises, the more the insect infestation and grain deterioration is magnified and can result in the entire crop being lost.

Until now, continuous temperature measurement has been a time-consuming chore which requires regular checks to ensure accurate readings. Using Sigfox devices for temperature monitoring reduces cost of deployment, cuts the farmer’s time spent overseeing the sensors, and ensures clear information is readily available in a straight-forward graphical display.

Fluctuating grain silo temperatures is a common problem for farmers. Monahan farms traditionally dealt with this by monitoring the grain temperature from the beginning of the storage period and blowing cool air through the grain when the temperature started to rise. A rise in temperature indicates a developing insect problem. If discovered in time, blowing cool air through the grain can solve the problem before it becomes established. This case outlines how VT/Sigfox devices have helped to achieve this.

The Challenge

Laborious and time-consuming temperature checks must be done regularly to prevent expensive infestations. Furthermore, grain quality assurance schemes are becoming increasingly common as a standard in grain production. These schemes demand detailed information about the production and storage of farmers’ crops. Temperature readings are required in order to prove the grain has been stored properly and that the temperature never rose above certain thresholds. This quality assurance is expected to become mandatory in the near future.

Monahan farms had been looking for a simple and cheap method of remotely monitoring the temperature in the grain. Some of the meters they were using gave readings, but were costly and the information they provided was not compiled in any useful way, so no trends could be acted on. The information coming from the sensors needed to be available as a graph on a computer or phone application and downloadable for use in a spreadsheet.  The temperature changes in the grain are slow, so it would only be necessary to report the temperature a few times a day. A rise in temperature over a few days or a week, preferably shown in graphs, would indicate a problem.

Temperature shift in grain is a sign of infestation, which can be monitored with temperature sensors

The Solution

Sigfox devices looked like an easy solution as they have a long battery life and do not require any sort of wired or Wi-Fi connection. After consulting with VT, Michael Monahan, of Monahan Farms, installed a Linobjec sensor in his grain silo and saw immediate results.

It has two sensors: one in the unit itself and another at the end of the attached two-metre cable. It signals the temperature every half hour. The attached probe reports the temperature from two metres down in the grain, which is contrasted to the air temperature above it.

As each module is battery equipped with a minimum lifetime of two years, it is very simple to install and simply read the data received on the application.  The Linobjec sensor has an operating temperature in range of -50 ° to +90 ° and a tolerance of +/- 0.5%. There are cable lengths of up to two metres available.

Michael is now able to view all the data on the web application, which is also transferred to the website for secure archiving. Each of the temperature results can be combined to show long-term trends on easy to access reports, which can then be retrieved in PDF or CSV (Excel) formatting.

A Linobjec temperature sensor, which communicates using Sigfox

Why Sigfox?


VT’s Sigfox network covers 96% of Ireland. This allows devices to communicate to the cloud, even in rural areas with poor cellular coverage. Since Sigfox doesn’t rely on local gateways, devices can be place out in the field or in the silo, without distance limitations.

 Long battery

Sigfox doesn’t require much energy to send a message, which means devices can operate on battery power for long periods of time. This makes it possible to install sensors in difficult to reach locations, such as a silo, because the devices require very little maintenance. The Linobject temperature sensor used on Monahan Farms only needs a new battery every two years.

 Low cost

Since Sigfox is optimized for simple devices, you don’t pay for data you don’t need. These leads to lower annual costs.


With the installation of a Linobjec temperature sensor, Michael no longer has to carry out manual checks of the temperature in his silo. The sensor automatically transmits readings several times a day, which Michael can view on his mobile or computer. These readings are also available in graphical form, making it easy to spot trends. The sensors have save Michael time, effort and help to safeguard his crop against expensive infestations and damage.

“The system is simple and works very well.”

Michael Monahan

“You install the device and thereafter can check the temperature on your phone from wherever you are. It displays a graph, so it is easy to see whether it is cooling or heating.”

Michael Monahan

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