Last Wednesday, I found myself hiking around in the hills above Silicon Valley, tramping down dried grasses and keeping an eye out for rattlesnakes, as warned. I was trailing Adam Wolf and Nona Chiariello as they hunted for a good spot in the Jasper Ridge Biological Preserve, 1200 acres of chaparral, redwood forest, and grassland owned by Stanford University, where Chiariello serves as a staff scientist. Their mission: to find the perfect location in which to pound in a metal post and mount the latest gadget to join the Internet of Things: Wolf’s Pulsepod.
Arable’s Pulsepod Photo: Tekla Perry
The Pulsepod is a sleek puck, about the diameter of a dessert plate, packed with sensors and communications gear, intended to watch plants grow (literally) as it simultaneously collects data about the environment around them. Wolf and his startup, Arable, intend to market the gadget as a $500 replacement for $10,000 weather stations with $5000 net radiometers. They expect the first users will be agricultural researchers and specialty crop farmers eager to monitor microclimates and plant growth in order to predict both long term effects of the environment on plants and to make short term decisions, like when to water and when to harvest.
The Pulsepod’s electronics include sensors that monitor six spectral bands in the visible and near infrared light frequencies. These determine how much plant material is in an area (plants absorb red wavelengths and reflect infrared wavelengths), measure the uptake of chlorophyll, and track moisture in both plants and in the air.
Tucked inside the puck, under an array of surface-mounted solar cells, are basic weather station sensors that measure humidity, barometric pressure, and temperature of both the foliage itself and the surrounding air. A net radiometer determines how much short and long wave radiation is coming down from the sun and how much is being reflected and radiated back. And an acoustic rain gauge, of the company’s own design, analyzes the sound of drops hitting the puck’s plastic top to determine the size and number of rain drops falling.
The gadget has Bluetooth, for checking functions on the spot, and cellular and Wi-Fi radios for streaming data remotely, and a tilt sensor to allow algorithms to correct for the device’s orientation and or send an alert if the device gets knocked over. A GPS receiver enables the streaming data to be automatically tagged with location information, and an auxiliary jack allows cameras or other upgrades to be added in the future.
“I claim that there is no IoT device that measures more data streams than this,” says Wolf. “It’s crazy to say and I’m willing to be proved wrong, but I haven’t met any device that tries to synthesize so much.”
Once installed in the field, the Pulsepod streams data to Arable’s cloud to be shaped into a form easily downloaded and manipulated by customers. The company also plans to use the data to develop proprietary algorithms for specialty crop forecasting.
Arable’s Adam Wolf holds a Pulsepod; the startup’s founder expects his $500 gadget to replace expensive weather stations like this one. Photo: Tekla Perry
Wolf, who has a masters degree in agronomy and PhD in biology, started getting involved in technology development in the early 2000s, when he was doing field work in Kazakhstan as part of his graduate research and realized that the weather stations he was setting up could do little to help him make sense of the vast region. They were limited in function, expensive, hard to install, and were unlikely to be clustered closely. He turned to satellite data, but found the available data was too noisy to be very useful, so he began studying and using numerical simulations to try to better assimilate it. Eventually, he decided the satellite data alone would never be good enough to allow him to forecast plant growth at a particular point on the globe. That’s when he started wiring together sensors and circuit boards to build a gadget that could do detailed monitoring of a particular spot of vegetation.
“It seemed,” Wolf told me, “that everyone doing global change research had become modelers; they were detached from empirical reality. Meanwhile, I saw art installations that were based on measurements of the environment. It was insane that artists were building things that were technically sophisticated while none of my scientist peers were making anything—when we really had a need for low power, low cost, data rich devices to measure our world.”
Wolf built his first prototype in 2010, and went on to build about a hundred more. In 2014, then a post-doctoral researcher at Princeton, his efforts got a big boost—a US $4 million grant from the National Science Foundation to do real-time drought monitoring and crop forecasting in east Africa, and $500,000 grant to monitor the drought impact on forests in the U.S. Southwest.
With news of the grant and updates on his work available online, people interested in the kind of low-cost monitor he was working on began to contact him. He heard from startups, government water districts, and insurance companies from around the world.
“It was an ‘Oh $#!%’ moment,” he recalls. “I was going to have to make hundreds of these things.” It was time for Wolf to leave academia and start a company—not a hard choice, it turns out, because, he says, “I was having more fun making tools to do science than writing peer reviewed papers about science.”
In 2014 Wolf officially started Arable with Ben Siegfried and Kelly Caylor. In 2015, the company stopped working directly on research funded by the NSF grants, and instead began supporting itself with angel investment from a former investment banker turned hay farmer.
Wolf is having an incredible time, immersing himself in the world of technology. Late last year he hired Ron Butterworth to finish the hardware design. In July, he contracted with Nest and GoPro designer Fred Bould to do the industrial design.
“I was climbing a Ponderosa Pine in New Mexico to install a prototype,” he recalls, “and had packed a GoPro to take pictures. I held it in my hand, and thought, I want my product to be cool like this. I checked out the designer, Fred Bould, and tried to hunt down someone who could get me an introduction. Finally, I just wrote to “info at Bould dot com” and he sent me an email back and agreed to meet. I described this data-packed thing that I wanted that I had no idea what it should to look like, just what it should measure. He went out and talked to farmers, and other potential customers to figure out how they would use it, how they would mount it, and came up with this design.” Wolf clearly is thrilled with the final product; he managed to have one in his hands most of the three hours I spent with him.
Photo: Tekla Perry
Right now, Arable has eight employees and offices in Princeton, Silicon Valley, and Nebraska. The company has manufactured 50 Pulsepods and is gradually rolling them out to beta customers around the world. It has several provisional patents granted on its technology, including its novel rain gauge design. The company is planning to close an investment round this summer, in time for a fall production run of 2000 with 10,000 planned to be manufactured next year.
Even with all this going on, this installation at Jasper Ridge is a big milestone, because the quiet ecological preserve has an important place in the history of plant monitoring: The early data that allowed remote satellite sensing to identify vegetation came from a JPL project, AVIRIS, that sent experimental imaging sensors flying over Jasper Ridge starting in the 1980s.
Wolf, Chiariello, Butterworth, Arable vice president of design Marisa Rowland, and I trudged around in the grasses for about an hour before Wolf settled on the perfect spot and Chiariello rounded up the right kind of mounting post. Once he pounded in the post, however, it took him just moments to set the Pulsepod on it and screw it down tight. After a little fidgeting to make sure the pod was roughly level and turned on, Wolf stepped back. “I’m content,” he said.
He expects this Pulsepod to be sending data to the cloud for five years; right now, he’ll just use the data to calibrate the net radiometer and spectrometer and fine tune the gadget’s power consumption, but eventually, it could replace the weather station (see photo) and other cumbersome gear used for field research at the preserve. And, Wolf thinks, someday it will do types of monitoring he has yet to imagine.
It’s like a Fitbit, he says: “You get it because you want to track your run, then you find out it measures your resting heart rate, you start noticing that some days its higher than others, and that turns out to be interesting to you, and you start using that to get healthier.” Like a fitness enthusiast, farmers, he thinks, will get obsessed with data about the plants growing in their fields and the slowly changing weather. “You show a wine grower data on their vines responding to the weather, and they can’t help but want to know more so they can do better.”
Tekla S. Perry is a senior editor at IEEE Spectrum. Based in Palo Alto, Calif., she's been covering the people, companies, and technology that make Silicon Valley a special place for more than 40 years. An IEEE member, she holds a bachelor's degree in journalism from Michigan State University.