This article was published 3/6/14 in the U Mass Extension Vegetable Notes series.

Wireless Stress Relief on the Farm

By Larry Manire, Databasics, Coventry, RI

Just think about no more stumbling through piled snow to feel exhaust stacks every hour, or that week in the spring where you set the alarm for 3 and 4 and 5am and, half asleep, tapping the thermometer, feeling the truck cab, and doing the mental gymnastics to decide if it’s warmer or colder where the strawberries are.  Now that can be over!

Recent advances in electronics and the Internet now make it possible to monitor conditions on the farm anywhere, anytime 24/7 without having to run wires all over the place.   You can place a small temperature sensor (a tiny computer with a “wireless” radio in it) in your greenhouse and tell it to report its temperature as often as you want to a “gateway”  (also a tiny computer) with a similar radio.  The radios use the unlicensed radio frequencies like those used by cordless phones and WiFi.

The gateway is either plugged into your Internet router back in the farm office, or connected to it via WiFi or it connects to cell phone towers like a mobile phone.   The gateway sends the sensor readings into a database stored on the internet.   You can then see that data on your farm’s “dashboard” using a browser on your computer, or an “app” on your tablet or cell phone to log in to your sensor “portal”.  But most importantly whenever the temperature is below or above a certain value you can tell the portal to send you and/or your crew an “alert” in the form of a text message or an email or a phone call notifying you of the condition.

There are hundreds of types of sensors.  The most useful for a farm measure temperature, humidity, soil temperature, soil moisture, leaf wetness, energy use, electric fence voltage, battery voltage, weather conditions, tank levels, water presence/absence, light, occupancy, and CO2 Levels.  You can also use wireless technology to turn on or off electrical devices and control valves and similar equipment from your computer or mobile device.

Although this technology has been available in industry for a decade it has only become truly affordable and practical for most farms in the past few years.  

I learned about this technology in 2011 when I was a volunteer at Brookfield Farm in Amherst, MA where my daughter Kerry was assistant manager with Dan Kaplan the manager.  Having a computer consulting background I started checking into using wireless sensors on the farm.  This led to Dan and myself obtaining a USDA SARE (Sustainable Agriculture Research and Education) Farmer Grant in 2012 titled Evaluation of Inexpensive, Wireless Sensor Networks for Managing Small Vegetable Farms.  Ruth Hazard from UMass Extension served as our technical advisor for the farming aspects of the project.  We tested sensors at Brookfield and also in two UMass research projects conducted by Ruth, one studying over-wintering of crops in low tunnels, the other comparing different high humidity storage facilities for a carrot crop.    

At Brookfield the alerts proved to be a resounding success.  In the spring Dan really appreciated knowing his cell phone would wake him up if the strawberry field was nearing freezing rather than him having to go out to the field at four in the morning to check on it.  In another case he was out of town and received an alert that the walk-in cooler was getting too warm.  He called crew and got it fixed right away.

At the same time we also learned about the difficulties of keeping sensors working on farms where there are bugs, dust, dirt, rain, sun, heat, cold, careless crew, errant tractors, long distances and many sources of radio interference such as hills, woods, steel, and stone walls.  We learned that you have to locate and manage sensors well to get the benefit.  You can’t just install and forget about them!

Getting started involves getting a gateway and perhaps a few sensors.  You can always add more sensors to the same gateway later.  Sensors can be moved around the farm as long as they can talk to the gateway.  “Repeaters” can be added to allow them to be further away from the gateway.

We’ve summarized our results and recommendations in a new informational website New England Farm Sensors (www.NEFarmSensors.org).    We explain the technology, list the sensor vendors we found most practical and affordable, and show sample deployments at early adopters Brookfield Farm, Red Fire Farm (Montague, MA), Provider Farm (Salem, CT) and Riverland Farm (Sunderland, MA). 

Hopefully you can learn enough from the website to design and install a wireless sensor network yourself.  Or if time is tight you can use one of the New England based consultants listed on the site to help out.