Sensor System and Methods for Chemical Detection

• US 20110014717A1
• Filed: 07/20/2010
• Published: 01/20/2011
• Est. Priority Date: 07/20/2009
• Status: Abandoned Application

• Current Assignee: Johns Hopkins University
• Original Assignee: Johns Hopkins University
• Inventors: Eaton, Harry A., Marrese, Carl A.
• Application Number:
  US12/839,579
• Publication Number:
  US 20110014717A1
• Time in Patent Office: Days
• US Class Current: 436/120
• CPC Class Codes: G01N 21/77 by observing the effect on a chemical indicator
• CPC Class Codes: G01N 31/224 for investigating presence of dangerous gases
• CPC Class Codes: G01N 33/0036 Specially adapted to detect a particular component all the other sub-groups of G01N33/0004 take precedence
• CPC Class Codes: Y10T 436/182 Organic or sulfhydryl containing [e.g., mercaptan, hydrogen, sulfide, etc.]
• CPC Class Codes: Y10T 436/196666 Carbon containing compound [e.g., vinylchloride, etc.]

Abstract

A miniature system encapsulating a chemical transducer (sensor) prepared for a specific chemical, coupled with a miniature radio transmitter that relays information to a handheld receiver on the presence, or absence, of the target chemical. The system is deployed by several means, such as grenade, small rocket, large caliber rifle, drone plane, etc. The deployment device can hold many such sensor devices, each prepared for a particular toxic chemical, such as chlorine, hydrogen sulfide, or phosgene.

Claims

1. A method for detecting a chemical comprising:

coating a light sensor with a formulation that reacts with the chemical to be detected to form a dye, wherein the formulation is transparent to light and the dye, when formed, is opaque;

transmitting light to the light sensor;

detecting a decrease in voltage of the light sensor when the light sensor is exposed to the chemical causing the dye to form thereby decreasing the amount of transmitted light received by the light sensor; and

determining the concentration of the chemical based on the decrease in voltage of the light sensor, the voltage decrease being proportional to the chemical concentration.

2. The method of claim 1, further comprising transmitting the decrease in voltage to a remote receiver.

3. The method of claim 1, further comprising triggering an alarm when the concentration of the chemical reaches a threshold level.

4. The method of claim 1, wherein the light sensor comprises a phototransistor.

5. The method of claim 1, wherein the light is transmitted by an LED.

6. The method of claim 1 wherein the formulation comprises lead acetate and the chemical comprises hydrogen sulfide.

7. The method of claim 1, wherein the formulation comprises one of a dichloromethane, toluene and chloroform solution containing a dye forming chemistry and the chemical comprises phosgene.

8. The method of claim 7, the dye forming chemistry comprising 4-Nitrobenzylpyridine and benzylaniline.

9. The method of claim 8, the dye forming chemistry further comprising polystyrene.

10. The method of claim 8, wherein the formulation is used to coat a layered hydrophobic surface.

11. A sensor system for detecting a chemical comprising:

means for transmitting light;

means for sensing the transmitted light;

a formulation for coating the sensing means, the formulation comprising a dye forming chemistry, the dye forming chemistry reacting with the chemical to form a dye, the dye being opaque and thereby reducing the light sensed by the sensing means causing a decrease in voltage of the sensing means that is proportional to the concentration of the chemical, the voltage decrease being used to detect the presence of the chemical.

12. The sensor system as recited in claim 11, further comprising:

means for transmitting the voltage decrease; and

means for receiving the transmitted voltage decrease.

13. The sensor system as recited in claim 12, wherein the receiving means is remote from the voltage decrease transmitting means.

14. The sensor system as recited in claim 11, further comprising means for triggering an alarm when the concentration of the chemical reaches a threshold level.

15. The sensor system as recited in claim 12, further comprising means for deploying the light transmitting means, the coated sensing means and the voltage decrease transmitting means remotely from the receiving means.

16. The sensor system as recited in claim 11, wherein the formulation further comprises a solution for containing the dye forming chemistry, the solution comprising one of dichloromethane, toluene and chloroform and the chemical comprises phosgene.

17. The sensor system as recited in claim 16, the dye forming chemistry comprising 4-Nitrobenzylpyridine and benzylaniline.

18. The sensor system as recited in claim 17, the dye forming chemistry further comprising polystyrene.

19. The sensor system as recited in claim 17, wherein the formulation is used to coat a layered hydrophobic surface.

20. The sensor system as recited in claim 11, the light transmitting means comprising an LED and the sensing means comprising a phototransistor.