ELECTRONIC GARDENING TOOL AND METHOD OF CONFIGURING THE SAME

• US 20110137563A1
• Filed: 12/07/2010
• Published: 06/09/2011
• Est. Priority Date: 12/07/2009
• Status: Active Grant

• Current Assignee: Luster Leaf Products, Inc.
• Original Assignee: Luster Leaf Products, Inc.
• Inventors: WILLIAMS, Mark B., Holbein, Larry L.
• Granted Patent: US 8,938,361 B2
• Time in Patent Office: Days
• US Class Current: 702/2
• CPC Class Codes: G01D 18/002 Automatic recalibration G01D18/008 takes precedence

Abstract

The tools and methods disclosed herein can convert an analog signal from the soil sensor probes into a digital format that can be read by a low cost digital microcontroller which acts on the digital data with formulae and tables so that the displayed information is the same or nearly the same as the readings in the same soil from the analog meters. To provide accurate readings, the described tools can apply either of a fixed or floating calibration method to set a reference of the measured soil pH and moisture measure. The floating calibration method also permits adjustment of the measure reference to correct calibration imprecision induced by fluctuation in the battery voltage.

Claims

1. An apparatus for measuring a soil characteristic, comprising:

a sensor circuit adapted to output an analog signal reflecting a measure of the soil characteristic;

an analog-to-digital converter adapted to convert the analog signal to a digital value;

a microcontroller receiving and processing the digital value; and

a display panel for displaying the measure of the soil characteristic;

wherein the microcontroller is configured to;

obtain a plurality of initial readings from the sensor circuit when the apparatus is powered on; and

assign a zero reference associated with a neutral value of the soil characteristic to a nominal value derived by averaging the initial readings.

2. The apparatus according to claim 1, wherein the analog-to-digital converter and the microcontroller are integrated into a same integrated circuit chip.

3. The apparatus according to claim 1, wherein the sensor circuit comprises:

a probe sensor; and

a signal conditioning circuit adapted to convert an output of the probe sensor to the analog signal processed by the microcontroller.

4. The apparatus according to claim 3, wherein the probe sensor includes a pH sensor adapted to measure a pH value of the soil.

5. The apparatus according to claim 3, wherein the probe sensor includes a moisture sensor adapted to measure a moisture value of the soil.

6. The apparatus according to claim 1, wherein the microcontroller is further adapted to detect a fluctuation in a battery voltage.

7. The apparatus according to claim 6, wherein the microcontroller is further adapted to readjust the zero reference according to the detected fluctuation in the battery voltage.

8. The apparatus according to claim 6, wherein the microcontroller is further adapted to:

process readings from the sensor circuit based on a timing variable defined in an embedded firmware, wherein the timing variable is set according to an internal clock signal of the microcontroller; and

adjust the timing variable according to the detected fluctuation in the battery voltage.

9. The apparatus according to claim 6, wherein the microcontroller is further adapted to rescale current digital data of the measured soil characteristic in accordance with the detected fluctuation in the battery voltage.

10. The apparatus according to claim 1, wherein the microcontroller includes a firmware that includes a first program code for pH measure computation and a second program code for moisture measure computation.

11. The apparatus according to claim 10, wherein the microcontroller is adapted to determine which of the first and second program code is to be run based on data outputted from the analog-to-digital converter.

12. The apparatus according to claim 11, wherein a first range of the data outputted from the analog-to-digital converter corresponds to a configuration of the sensor circuit incorporating a moisture sensor, and a second range of the data outputted from the analog-to-digital converter corresponds to a configuration of the sensor circuit incorporating a pH sensor.

13. The apparatus according to claim 12, wherein the first range is located around a first output voltage of the sensor device equal to 0, and the second range is located around a second output voltage of the sensor device above zero volt.

14. The apparatus according to claim 1, further comprising a processing unit coupled with the microcontroller, wherein the processing unit is adapted to keep a database including plant type information, care and target values, usage monitoring for recording favorites, and input scanning information.

15. The apparatus according to claim 1, wherein the microcontroller is further adapted to temporarily hold the display of last measure data of the soil characteristic.

16. A method of configuring an electronic gardening tool adapted to measure a soil characteristic, wherein the electronic gardening tool includes a sensor circuit and a microcontroller, and the method comprising:

as the electronic gardening tool is powered on, obtaining a plurality of initial analog readings from the sensor circuit;

averaging the initial analog readings to obtain a nominal value; and

assigning a zero reference associated with a neutral reference value of the soil characteristic to the nominal value.

17. The method according to claim 16, further comprising:

detecting a fluctuation in a battery voltage of the electronic gardening tool.

18. The method according to claim 17, further comprising:

readjusting the zero reference according to the detected fluctuation in the battery voltage.

19. The method according to claim 17, further comprising:

processing readings from the sensor circuit based on a timing variable, wherein the timing variable is set according to an internal clock signal of the microcontroller; and

adjusting the timing variable according to the detected fluctuation in the battery voltage.

20. An apparatus for measuring a soil characteristic, comprising:

a sensor circuit adapted to output an analog signal reflecting a measure of the soil characteristic;

a microcontroller coupled with the sensor circuit, wherein the microcontroller includes an analog-to-digital converter adapted to convert the analog signal to a digital value;

a display panel for displaying the measure of the soil characteristic; and

a calibration circuit adapted to set a zero reference associated with a neutral value of the soil characteristic to a fixed reference voltage from the sensor circuit.

21. The apparatus according to claim 20, wherein the calibration circuit includes a variable resistor, and the calibration circuit is connected between the sensor circuit and the microcontroller.

22. The apparatus according to claim 20, wherein the sensor circuit includes a pH sensor, a moisture sensor or both a pH sensor and a moisture sensor.

23. The apparatus according to claim 20, wherein the microcontroller is programmed to hold a digital value corresponding to a measured soil characteristic on the display for a predetermined period of time, after the soil characteristic has been measured.

24. The apparatus according to claim 20, wherein the microcontroller is programmed to recognize sudden lowering in a value of a measured soil characteristic and continue to display the measured value obtained before the sudden change occurred.

25. The apparatus according to claim 20, wherein the microcontroller is programmed to recognize a sudden increase in a value of a measured soil characteristic to a new measured value, and display the new measured value instead of a prior displayed value.