South Dakota farmer builds bin control for $100 instead of $80K
A western South Dakota farmer wanted a bin aeration control system he could operate from his smartphone. When he learned it would cost $80,000 he used his tech savvy to build his own — for $100.
PRESHO, S.D. — Adam Ehlers wanted a remote-control bin fan system, he just didn’t want to pay $80,000 for it.
“Too much of a cheap farmer,” chuckles Ehlers, 43, who farms at Presho, S.D., under the Ehlers Grain LLC banner. The farm headquarters dominates the west side entry to a town of about 550 people in Lyman County. The farm has about 4,000 acres of crops, including winter wheat, spring wheat, milo, sunflower, soybeans and a little millet.
Ehlers said he got tired of forgetting to turn off his aeration.
“In the middle of the night I’d have to jump out of bed and go turn my fans off. Or I’d be gone and it’d start raining and I had to turn my fans off,” he said. “So I always wanted a way to be able to turn off fans from a smartphone.”
He priced the system and he was told it might cost about $8,000 per bin. His site has 10 bins, so that would be about $80,000. He thought there had to be an easier way to get 80% of the features at a fraction of the cost.
He attended Farmer-2-Farmer convention and talked to vendors at gatherings. Most said he’d have to pay $1,000 apiece, per bin.
“I said there’s got to be a way to have one master switch and use Wi-Fi to control the other bins.”
Ehlers acknowledges he has a mind for technology.
In 2002, he graduated from the South Dakota School of Mines and Technology in Rapid City. With his degree in mechanical engineering he worked with the Department of Defense as a nuclear test engineer on Navy aircraft carriers.
In college, he’d met his future wife, a Norwegian, Kjersti (“KJ”), a mechanical engineer and teacher. From 2005 to 2010 they lived in Norway, where he did structural engineering on off-shore oil drilling rigs. They have two children.
About 11 years ago he moved back to take over the family farm from his father. After school is out in the spring, KJ takes the kids to Norway for several weeks while Adam is busiest on the farm.
Hardwood or grain
Adam was ready to install his bin system in early 2019.
He got in touch with a system that is used to control humidity in houses, designed especially for keeping hardwood floors in good shape.
“I found it on the internet, bought a couple of temperature and humidity monitors, and 10 smart switches. I hooked it up to my bins and it worked,” he said. “So I have all 10 bins hooked up for less than $100, rather than $80,000.”
The system includes a Sonoff TH16, which cost roughly $24.
“Then you have ‘smart switches,’ that are $6. You can turn on and off the smart switch with a smartphone," he said.
Everything is run by the "eWeLink" app, which can tell the outside temperature and humidity. The app connects to a “eWeLink” switch.
The system allows him to set a “scene.” For example, he can have the system automatically turn on when the outside temperature is between 50 and 80 degrees F, or when the relative humidity is between 50% and 70%.
He uses charts for each grain for equilibrium moisture content.
“I look up the desired equilibrium on the chart, and find my desired moisture, and then it shows the temperature and humidity range the fan needs to run at,” he said.
“You don’t know what the temperature is in the bin,” he said. But the system affords as much control as he needs, especially for the price.
He added a sensor to monitor air coming out of the bin as well.
“Usually you get a bit of heat increase just from the friction of running the fan,” he said. “I’m still learning a little bit every day.”
In one money-saving measure, he uses an internet connection that he shoots from his mother’s nearby house across South Dakota Highway 16, the main road going into town.
“It’s like a wireless bridge, that acts like having ‘Cat5’ cable, running across the highway,” he said. He has another router for Wi-Fi on this side of the road. He uses a Ubiquiti brand NanoStation “local” to send out his signal. The Wi-Fi runs in the 2.4 GHz range to run the smart switches. (“If you have a 5 GHz Wi-Fi router, it won’t work,” he cautions.)
In the future Ehlers plans to try a smartphone hot spot for a remote bin site.
“The best thing is if you’re laying in bed in the middle of the night, and the fan is still running, you can look on your phone and be able to see the fan is still on and just turn off your controller,” he said.