Fluid dispenser having infrared user sensor

• US 7,896,196 B2
• Filed: 06/27/2007
• Issued: 03/01/2011
• Est. Priority Date: 06/27/2007
• Status: Active Grant

• Current Assignee: GOJO Industries Incorporated
• Original Assignee: Joseph S. Kanfer
• Inventors: Wegelin, Jackson W., Curtis, Chip W.
• Primary Examiner(s): Bastianelli; John
• Application Number:
  US11/823,248
• Publication Number:
  US 20090000023A1
• Time in Patent Office: 1,343 Days
• Field of Search: 251/129.04, 250/210, 250/214.R, 222/52, 462/3
• US Class Current: 222/52
• CPC Class Codes: A47K 5/1217 Electrical control means for the dispensing mechanism
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/88 Lidar systems specially adapted for specific applications
• CPC Class Codes: G01S 7/486 Receivers

Abstract

A dispensing system is disclosed which utilizes a controller in conjunction with a photodetector in order to provide automatic dispensing to a user when an object enters a target area. A controller is programmed to pulse a light source that is mounted proximate the photodetector. The controller constantly monitors the voltage at the receiving signal of the photodetector, and evaluates the difference in voltage from the light pulsed on and off. The controller sums the differences, and constantly updates the differences over a designated period to create an average difference value. The average difference value is summed with a target offset value and compared to a momentary voltage difference. When the momentary difference exceeds the sum of the target offset value and average difference, the controller sends a signal to a dispense mechanism which dispenses a fluid or other product on the object.

Claims

1. A hands-free dispenser for dispensing a product into a target area, comprising:

a dispensing mechanism;

a light emitting diode associated with said dispensing mechanism;

a controller; and

a photodetector positioned so as to detect reflected light from said light emitting diode that represents light levels of a target area and which generates a voltage received by said controller that corresponds to detected light levels,

said controller programmed to;

determine an Active Voltage value recorded from said photodetector when said light emitting diode is on;

determine an Ambient Voltage value recorded from said photodetector when said light emitting diode is off;

determine an Average Difference value based on a series of Active Voltage values minus Ambient Voltage values;

determine a Momentary Difference value equal to the difference between an Ambient Voltage value and an Active Voltage value;

set a Target Level Offset value, and

send a signal to said dispensing mechanism when said Momentary Difference value exceeds said Average Difference value plus said Target Level Offset value so as to dispense the product into the target area.

2. The dispenser according to claim 1 wherein said photodetector comprises either a photodiode or a phototransistor.

3. The dispenser according to claim 1 wherein said light emitting diode is an infrared light emitting diode powered by said controller and said controller pulses said diode for less than 150 microseconds each time said controller searches for an object in the target area.

4. The dispenser according to claim 1 wherein said controller operates between 1 MHz and 20 MHz when searching for an object in the target area.

5. The dispenser according to claim 4 wherein said controller stops when not looking for the object in the target area.

6. The dispenser according to claim 4 wherein said controller maintains an oscillator which continues to run when said controller is not searching for the object.

7. The dispenser according to claim 4 wherein said voltage is measured using a successive approximation register analog to digital converter.

8. The dispenser according to claim 4 wherein said voltage is measured using a comparator.

9. The dispenser according to claim 1 wherein said infrared light emitting diode is an infrared light emitting diode that operates between 200 mA to 1.5 A when pulsed by said controller.

10. The dispenser according to claim 1 wherein said controller calculates a Difference Value from an Active Voltage Value generated when said light emitting diode is on, and an Ambient Voltage value generated when said light emitting diode is off, wherein said Average Difference value is calculated by averaging a number of Difference Values per second over a predetermined period of time.

11. The dispenser according to claim 1 wherein said Difference Values that are negative are omitted from said Average Difference calculation.

12. The dispenser according to claim 1 wherein said Momentary Difference value is included in said Average Difference Value when said Momentary Difference value is less than a sum of said Average Difference and said Target Offset.

13. The dispenser according to claim 1 wherein said Average Difference value is updated whenever a Momentary Difference value is taken.

14. The dispenser according to claim 1, wherein said Target Offset value is a fixed value.

15. The dispenser of claim 1 wherein said Target Offset value is calculated by said controller.

16. The dispenser according to claim 1, wherein said Target Offset value is based on a percentage of said Average Differences.

17. The dispenser according to claim 1 wherein the product is a liquid.

18. The dispenser according to claim 1 wherein the product is a skin-care product.

19. The dispenser according to claim 1 wherein the product is soap.

20. A method for dispensing product, comprising:

pulsing a light emitting diode;

positioning a photodetector proximate said light emitting diode so as to detect reflected light therefrom;

reading and storing an Active Voltage value from said photodetector detecting reflected light when said light emitting diode is illuminated;

reading and storing an Ambient Voltage value from said photodetector detecting any light when said light emitting diode is not illuminated;

calculating a Momentary Difference between said Active Voltage value and said Ambient Voltage value;

calculating an Average Difference value based on a series of Active Voltage values minus Ambient Voltage values over a time interval;

comparing said Momentary Difference to a sum of an Average Difference and a predetermined Target Offset value;

generating a signal to dispense when said Momentary Difference is greater than said sum; and

dispensing the product when said signal to dispense is received by a dispensing mechanism.

21. The method according to claim 20 wherein the product is liquid.

22. The method according to claim 20 wherein the product is a skin-care product.

23. The method according to claim 20 wherein the product is soap.

24. The method according to claim 20 wherein the product is paper.

25. The method according to claim 20 wherein said light emitting diode is an infrared light emitting diode that is pulsed for less than 150 microseconds.