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Wireless Spray Monitor on the Way

One day, you may want to thank an agricultural engineer named Joe Luck for his work with spray drift.

For now, he’s only in the early-stage development of his idea to monitor spray droplets for size and distribution with wireless technology. This could replace the tedium of using water-sensitive paper cards to capture the spray pattern from a new or worn set of nozzles.

For agricultural engineers, it could be a cheap, in-field, real-world alternative for testing nozzle performance. It could replace expensive laser particle-size analyzers in labs.

“Spray drift is a big issue for applicators,” says Luck, a precision agriculture engineer at the University of Nebraska. “The EPA is working on amendments and guidelines for reducing spray drift. As researchers, we would like to improve our sensing options for spray droplets and nozzle application rates and to make it a faster system.”

Checking nozzles
Nozzle spray patterns change with pressure, wear, corrosion, and nozzle material buildup. After 6,000 acres, it may be time for a new set.

To check nozzles, ground applicators turn on a water spray and watch for any spray-pattern differences. To check the rate, they may hold a bucket under one nozzle for a timed trial.

Aerial applicators can test while the aircraft is parked, but they need proof for what actually happened while cruising over a field at 80 mph.

To do that, most aerial applicators frequently check spray distribution and droplet size by flying over a set of 1×3-inch treated water-sensitive paper cards. Droplet size and pattern can be measured and adjusted.

It takes time and a helper, but it’s the only method they can use to really prove the rate and pattern that was requested by a customer.

In labs, nozzle testing usually involves a laser beam with a photocell. As the beam crosses a spray pattern, it can read the spray pattern and droplet sizes. When they know the pattern, agricultural engineers can develop new types of nozzles and can predict the amount of drift with different wind conditions.

“About eight years ago, a few researchers tried to look at electronic sensing for spray droplets and potential application rates for nozzles. That research ended, but they had some promising ideas. One was the need for inclusion of wireless sensor networks. Deploying a few of these sensors that could communicate output wirelessly seemed like a feasible idea,“ Luck says.

The engineer and a student developed a small square array on a 3-inch circuit board with eight sensors feeding data into a central circuit in cooperation with a former colleague, Mike Sama, at the University of Kentucky.

They used three sensor patterns. When a sensor was saturated, it produced a signal. Under the circuit board, they attached a wireless system for data logging and sending messages to a central computer.

Preliminary results from the 2014 trial were promising, Luck says, but the idea needs much more development and testing.

“There could be some real deployment someday,” Luck says. “If you have an area you want to monitor for spray drift or if you want to get an idea of application rates or particle sizes, we probably could do it with a wireless system.”

With one sensor array, you could get instant feedback on application rate at the point of measurement. Multiple sensor arrays would be required for a long strip along a field boundary.

Will it develop into something useful? It’s worth trying, Luck says.

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