A Reliable Switch that is Triggered by the Detection of a Specific Gas or Substance

 An integrated smart device which combines the functions of a mass threshold value gas sensor and an electro-mechanical (MEMS) switch that actuates an alarm or defensive security system.  

Background:

A smart switch that is actuated on the detection of a substance. The centerpiece of this “smart” switch electro-mechanical technology is an analyte-coated microbeam which can sense an explosive gas or biological substance. The principle of operation is that the absorption of the chemical or bio agent changes the mass on the cantilevered beam, which collapses and closes an electric circuit to activate a safety alarm or countermeasure.

 Technology Overview:  

The novel active structure can be engineered into MEMS devices used to sense a variety of biologics, chemicals, explosives, allergens, drugs, pollutants, and, nano-engineered materials. The invention relies on electrostatic actuation of a parallel plate capacitor, Figure 1, in which one plate (or any other structure of arbitrary shape) is stationary and the other plate is movable and is actuated or biased by an electrostatic DC force. The device integrates the functionality of separate components (sensors, actuators, decision units, amplifiers, analog to digital converters) into one package. High reliability is built into the design of the device: the switch will operate only when the concentration of the hazardous gas or material exceeds an encoded threshold value. The device has the ability to deploy in the field and detect in real time without use of lab and is simple and inexpensive to batch-fabricate, calibrate and operate.

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 Advantages:  

• Simple and inexpensive to batch-fabricate, calibrate and operate
• Low-power, low-weight, small foot-print design
• Built-in reliability – the switch operates only when the concentration of the hazardous gas or material exceeds an encoded threshold value
• Speed – ability to deploy in the field and detect in real time without use of lab  

 Applications:  

• The invented device can operate as a chemical sensor or as a biosensor
• Defense and Homeland Security, e.g., detect explosives such as TNT and bio- and chemical warfare agents, including anthrax
• Environmental, e.g., an array of “electronic noses” detect ozone, solvent vapors and VOCs, radon, ammonia, smoke and pollutants in factories, furnace rooms, residences, public buildings, casinos, nursing homes, dry cleaners
• Food Safety, e.g., detect dangerous concentrations of bacteria and send a signal to pull the foodstuffs from the processing line for further inspection
• Transportation, e.g., detect fugitive emissions in fueling facilities and parking garages, including Hydrogen, compressed natural gas, carbon monoxide
• Mine Safety, e.g., detect concentrations of methane and combustible gases 

Intellectual Property Summary:

• U.S. 8,168,120
• U.S. 8,501,097