Science

Tiny, cheap water-sensing chip outperforms larger, pricier sensors

Tiny, cheap water-sensing chip...
Doctoral student Vinay Pagay holds one of the chips
Doctoral student Vinay Pagay holds one of the chips
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Doctoral student Vinay Pagay holds one of the chips
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Doctoral student Vinay Pagay holds one of the chips
One card can reportedly last outdoors for at least a few years, although freezing temperatures may cause it break
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One card can reportedly last outdoors for at least a few years, although freezing temperatures may cause it break

Whether you're growing wine grapes or mixing cement, there are some situations in which it's vitally important to monitor moisture content. Normally water sensors are used, although these can be both large and expensive. Now, however, a team from Cornell University has created a water-sensing silicon chip that's not only tiny, but is also reportedly "a hundred times more sensitive than current devices." What's more, the chips might be possible to mass-produce for just $5 a pop.

Known as a "lab on a chip" device, the chip contains a tiny water-filled cavity. Once placed in soil, inserted in the stem of a plant, stuck in a cement matrix or put somewhere else, the chip exchanges moisture from that cavity with moisture in its environment via a nanoporous membrane. The chip measures any changes in the pressure within the cavity, that result from water either entering it or being drawn out.

One card can reportedly last outdoors for at least a few years, although freezing temperatures may cause it break
One card can reportedly last outdoors for at least a few years, although freezing temperatures may cause it break

In order to relay the data it gathers, the chip must be connected to a Wi-Fi card, a data logger, or some other device that can either transmit or record information. One chip can reportedly last outdoors for at least a few years, although freezing temperatures may cause it break.

The Cornell researchers are now establishing how moisture readings made by the chips translate to plant growth, so that users can make sense of their data.

Already, Welch's juice company and the Ernest and Julio Gallo winery have expressed interest in the technology.

Source: Cornell University

7 comments
Grunchy
Quality hygrometers are notoriously expensive, I'd love to buy one cheap so I can monitor the basement.
james___uk
So you say they are expensive now but will become cheap, I don't suppose these will be available within the next 150 days?
pmshah
I wonder if this is really all that great a story ! In most cases like what Grunchy refers to it is relative humidity that one would be interested in monitoring. I bought a monitor that tracks the temperature and humidity for under $ 10/=. I find the temperature to be accurate to within 1/2 a degree Celsius and RH to within 2 - 3 %. This should serve for most of the Household situations.
christopher
I think some existing ones are dangerous as well, using radioactive decay to determine moisture content. (My Geiger counter went off one day when a farmer parked near me, and some sleuthing later revealed his explanation: he'd "been meaning to fix the case on the moisture tester for some time"...)
John Findlay
I'm thinking that this device could be used in electronic devices that are used in harsh enviroments where water ingress will potentialy cause failure.
solutions4circuits
It's a good thing these are planned to be used where there aren't any chemicals (like ammonia fertilizers, herbicides, etc), there isn't any dirt, or presence of other materials, that can block the membrane or contaminate the reference well...oh, wait a minute...
Fretting Freddy the Ferret pressing the Fret
Is this chip a demonstration of a chemical sensor based on zeolite membrane technology? I don't know any specifics about the nanoporous membrane, but if it has hydrophilic groups on its surface and narrow pore size distribution I think it will work very well. In that case, likely the sensor is designed to have very high selectivity through molecular sieving and so diffusion of water through its pores over less polar contaminants will be dominant. How curious.