STUD SENSOR
First Claim
1. A sensing device having a sensing surface for placing against a wall for detecting objects behind a wall lining comprising:
- a first sensor comprising at least first and second capacitor plates and first and second resistors forming first and second RC circuits having first and second time constants dependent on adjacent wall material;
a first detection circuit connected to the first and second RC circuits and providing a first voltage signal sfhaving an amplitude dependent on a change in the first and second time constants of the first and second RC circuits;
a second sensor comprising at least third and fourth capacitor plates and third and fourth resistors forming third and fourth RC circuits having third and fourth time constants;
a second detection circuit connected to the third and fourth RC circuits and providing a second voltage signal having an amplitude dependent on a change in the third and fourth time constants;
comparison means receiving the first and second voltage signals, and comparing the first and second voltage signals to establish magnitude of voltage difference between the first and second voltage signals, and indicating a detected object center position when the voltage difference is less than a predetermined value.
2 Assignments
0 Petitions
Accused Products
Abstract
A sensing device having a sensing surface for placing against a wall for detecting objects behind a wall lining has first and second sensors, each sensor including at least first and second capacitor plates and associated resistors forming RC circuits having time constants dependent on the adjacent wall material. Detection circuits connected to the RC circuits provide first and second voltage signals having amplitudes dependent on capacitance changes. A processor effects a comparison of the first and second voltage signals, and compares them to establish the magnitude of the voltage difference between the voltage signals, indicating a detected object center position when the difference signal is less than a predetermined value.
-
Citations
19 Claims
-
1. A sensing device having a sensing surface for placing against a wall for detecting objects behind a wall lining comprising:
-
a first sensor comprising at least first and second capacitor plates and first and second resistors forming first and second RC circuits having first and second time constants dependent on adjacent wall material; a first detection circuit connected to the first and second RC circuits and providing a first voltage signal sfhaving an amplitude dependent on a change in the first and second time constants of the first and second RC circuits; a second sensor comprising at least third and fourth capacitor plates and third and fourth resistors forming third and fourth RC circuits having third and fourth time constants; a second detection circuit connected to the third and fourth RC circuits and providing a second voltage signal having an amplitude dependent on a change in the third and fourth time constants; comparison means receiving the first and second voltage signals, and comparing the first and second voltage signals to establish magnitude of voltage difference between the first and second voltage signals, and indicating a detected object center position when the voltage difference is less than a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
-
16. A method of detecting objects beneath wall linings using a sensing device having:
-
a first sensor comprising at least first and second capacitor plates and first and second resistors forming first and second RC circuits, and a first detection circuit providing a first voltage signal having an amplitude dependent on a change of time constants of the first and second RC circuits; and a second sensor comprising at least third and fourth capacitor plates and third and fourth resistors forming third and fourth RC circuits, and a second detection circuit providing a second voltage signal having an amplitude dependent on a change of time constants of the third and fourth RC circuits, the method comprising repeatedly detecting the first and second voltages as the sensor is moved over the wall lining, calculating a difference signal, and indicating an object center position when the difference signal is below a predetermined value. - View Dependent Claims (17, 18, 19)
-
Specification