28 Jun 2018
IoT and MEMS in Connected Agriculture
Mark Patrick, Mouser Electronics looks at how the Internet of Things, IoT will bring benefits to areas like agriculture where automation is the key to financial success.
Agriculture was one of the earliest and most revolutionary inventions in human history. Ever since, feeding the world’s growing population has depended on technological advances, from the plough to modern pesticides, to increase productivity and prove Malthus wrong.
In the last few decades, the use of electronic measurement and analysis has led to the development of precision agriculture to further improve productivity. This allows farms to increase yields, reduce the use of water, fertilizer, pesticides and weedkillers, and generally have a lower impact on the environment. Some of these techniques depend on satellite imaging and large scale deployments of expensive equipment that are only available to industrial scale farming.
These systems allow real-time data gathering and analysis to monitor the status of soil, crops, and livestock. This enables more accurate planting, feeding, spraying and harvesting, and the monitoring animal welfare. Precision measurements can be used to determine the amount of water, fertilizer and pesticide required for each area within a field.
Recent technological advances, partly driven by the market for mobile devices and the Internet of Things (IoT), mean that systems combining sensors, processing and communications are within reach of many more farmers. This is enabling new markets and applications in connected agriculture. A modern farmer is as likely to be out in the field with a smartphone as traditional agricultural tools.
Much of the measurement and sensing required for agricultural applications depends on micro-electromechanical systems (MEMS). These combine mechanical structures with electronics to create sensors, controllers and energy harvesters. These intelligent sensing systems have the advantages of small size, low cost and low power. The integrated electronics can provide control, data gathering, self-calibration and communication. On-board processing allows some computation to be done locally, providing immediate feedback and reducing the amount of data that has to be sent over the network. To be useful, MEMS-based products must be low cost, easy to install and use, and have a long lifetime in the field. They need to be physically robust and use little power; lasting for years on batteries, solar power or energy harvesting technology.
As increasing amounts of data are collected good algorithms are required to make sense of it. The systems also need well-designed user interfaces to display the results and allow farmers to exploit the information without having to become experts in data processing.
MEMS sensors include gyroscopes, accelerometers and magnetometers as well as devices for measuring pressure, sound and humidity. Some sensors are more specific to agriculture, such as wind speed and direction, pH, soil water content and displacement sensors used to measure movement or growth of a plant stem or fruit. MEMS devices can be used for energy harvesting, for example from the movement of the device. They can also be used to form actuators and lab on a chip (LOC) systems.
Figure 1: Murata SCC2000 MEMS accelerometer and gyroscope. (Source: Murata)
A combined accelerometer and gyroscope, such as the Murata SCC2000, see Figure 1, can be use to augment existing technology, such as GPS, by providing local information about terrain and allowing more accurate positioning for plowing and planting seeds. This is illustrated in Figure 2.
Figure 2: Correcting GPS position due to tractor on an angle. (Source Murata)
Accelerometers are also used to monitor the activity of livestock; how much time cattle spend walking, eating or lying down. This can provide important information about their health. For example, changes in gait may indicate lameness. The amount of time spent eating and ruminating (re-chewing partly digested grass) can be used ensure that the animals are getting adequate nutrition. Also, the level of activity increases dramatically when cows are ovulating. This often happens at night which means farmers may not be in time to get a bull to the scene for calf making. Real-time monitoring can detect when ovulation is happening and send an alert to the farmer.
Another use of MEMS sensors is for monitoring animal welfare, for example recording conditions such as temperature, humidity and noise. On the farm these will be reasonably constant but could be extremely variable during transport. The data can be recorded, along with GPS location information, to ensure that conditions are within the prescribed limits.
The lab on a chip (LOC) is a relatively new development. It integrates one or more laboratory functions onto an integrated circuit (IC) a few mm or cm in size. For example, a cantilever (a beam suspended at one end, like a microscopic diving board) can be coated with receptors that will bind with particular toxin molecules or viruses. The presence of the target molecule will change the resonant frequency of the cantilever so that the presence and concentration of the pathogen can be detected. Multiple cantilevers can be constructed, each sensitive to a different pathogen. Other biochemical sensors use changes in capacitance as molecules bind to the structure.
These devices can be used for automated and high-throughput (ideally, real time) processing and screening using small (picoliter) volumes of the material to be tested. This enables fast analysis in the field, rather than having to send samples to a pathology lab then waiting days or weeks for a result. LOC has potential applications in food safety (checking for pathogens or contamination in food products), animal disease prevention (checking for mastitis when milking cows) and analyzing soil nutrient levels.
There are many applications for MEMS sensors in connected agriculture currently being developed or marketed.
Moocall is a tail-mounted accelerometer that detects when calving is most likely to occur from the distinctive patterns of tail movement caused by labor contractions. When these reach a certain level of intensity over time, the system sends an SMS text alert directly to a cell phone. This typically gives notice an hour before calving, allowing the farmer to get to the cow and ensure that the birth is successful.
The Analog Devices (ADI) “Internet of Tomatoes” project uses MEMS sensors placed among the plants to measure motion, temperature, light and humidity. The sensors are rugged and the batteries can last several seasons, so the maintenance overheads are minimal. Data is transmitted via Bluetooth to the cloud for analysis. This is used to provide farmers with real-time data and trends so that they can intervene promptly to ensure the correct level of watering, know the best time to harvest and so on. Aggregating this information can provide information for planning the planting and harvesting schedules for future seasons.
CattleWatch provides collars that are used to monitor the location and activity of cattle. A small subset of the herd wear solar powered collars that can transmit data via satellite phone. The other animals are connected to these via an in-herd mesh network. Data is made available to the farmer via a smartphone app.
The PulsePod from Arable is a six-band spectrometer, four-way net radiometer and acoustic rain gauge that measures rain, hail, canopy leaf area, crop water demand, environmental stresses, microclimate and several other parameters. It is wirelessly connected using Bluetooth and Wi-Fi. The data can be used to manage irrigation and plan harvesting.
There is a wide range of possible applications for MEMS and IoT technologies in farming. These will become more widely accessible as the market grows and costs fall. With the world’s population forecast to approach 10 million in the second half of this century, this technology will be increasingly important for increasing agricultural productivity while minimizing the environmental impact.
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About the author
Mark joined Mouser Electronics in July 2014, having previously held senior marketing roles at RS Components. Prior to RS, Mark spent 8 years at Texas Instruments in Applications Support and Technical Sales roles. He holds a first class Honours Degree in Electronic Engineering from Coventry University.
Mouser Electronics, a subsidiary of TTI, Inc., is part of Warren Buffett's Berkshire Hathaway family of companies. Mouser is an award-winning, authorized semiconductor and electronic component distributor, focused on the rapid introduction of new products and technologies to electronic design engineers and buyers. Mouser.com features more than 4 million products online from more than 500 manufacturers. Mouser publishes multiple catalogs per year providing designers with up-to-date data on the components now available for the next generation of electronic devices. Mouser ships globally to over 500,000 customers in 170 countries from its 492,000 sq. ft. state-of-the-art facility south of Dallas, Texas.
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