Grip detection and capacitive gesture system for mobile devices
Apparatus and methods are disclosed related to managing characteristics of a mobile device based upon capacitive detection of materials proximate the mobile device, a capacitive gesture system that can allow the same gestures be used in arbitrary locations within range of a mobile device. One such method includes receiving a first capacitive sensor measurement with a first capacitive sensor of the mobile device. The method further includes determining a value indicative of a material adjacent to the mobile device based on a correspondence between the first capacitive sensor measurement and stored values corresponding to different materials. The method further includes sending instructions to adjust a characteristic of the mobile device based on the determined value indicative of the material adjacent to the mobile device. In certain examples, gesture sensing can be performed using capacitive measurements from the capacitive sensors.
1. A non-transitory computer-readable medium comprising code that, when executed by a processor, causes an apparatus to:
receive capacitance measurements measured by at least two capacitive sensors of a handheld device, including: (1) left capacitive sensor configured to provide capacitance measurements related to a first portion of a hand adjacent to the left side of the handheld device and (2) right capacitive sensor configured to provide capacitance measurements related to a second portion of the hand adjacent to the right side of the handheld device; and
determine a type of grip of the hand on the handheld device based on the capacitance measurements, wherein the capacitance measurements include a differential capacitance measurement between the left capacitive sensor and the right capacitive sensor, a single-ended capacitance measurement of the left capacitive sensor, and a single-ended capacitance measurement of the right capacitive sensor; and
apply a predetermined algorithm, wherein applying the predetermined algorithm comprises:
calculating a magnitude of the differential capacitance measurement between the left capacitive sensor and the right capacitive sensor; and
calculating a sum of (1) the single-ended capacitance measurement of the left capacitive sensor, and (2) the single-ended capacitance measurement of the right capacitive sensor,
wherein the magnitude of the differential capacitance measurement and the sum are used by the algorithm to determine the type of grip, and
wherein the type of grip specifies placements of the palm, digits, and thumb on the handheld device in a particular configuration.
2. The medium of claim 1 , wherein:
determining the type of grip of the hand comprises accessing a multi-dimensional algorithm stored on a memory using the capacitance measurements.
3. A method for grip detection on a handheld device using environmental capacitive sensing, the steps comprising:
receiving capacitance measurements measured by at least two capacitive sensors, including: (1) a first capacitive sensor configured to provide capacitance measurements related to a first portion of a hand and (2) a second capacitive sensor configured to provide capacitance measurements related to a second portion of the hand;
calculating a differential capacitance measurement between the first capacitive sensor and the second capacitive sensor;
calculating a sum capacitance measurement from the first capacitive sensor and the second capacitive sensor;
applying an algorithm to one or more of the capacitance measurements, wherein the capacitance measurements comprise: single-ended capacitance measurement of the first capacitive sensor; single-ended capacitance measurement of the second capacitive sensor; differential capacitance measurement; and, sum capacitance measurement; and
determining a type of grip of the hand based on the application of algorithm to capacitance measurements,
wherein, the type of grip specifies placements of the palm, digits, and thumb on the handheld device in a particular configuration.
4. The method of claim 3 further comprising the step of connecting the first capacitive sensor to a positive input of a differential amplifier front-end to an analog-to-digital converter and the second capacitive sensor to a negative input of the differential amplifier front-end, or vice versa to obtain the differential capacitance measurement between the first capacitive sensor and the second capacitive sensor.
5. The method of claim 3 wherein,
the at least two capacitive sensors includes a further capacitive sensor;
the type of grip of the hand on the handheld device is determined based further on one or more of: (1) a differential capacitance measurement between the first capacitive sensor and the further capacitive sensor, (2) a differential capacitance measurement between the second capacitive sensor and the further capacitive sensor, and (3) a single-ended capacitance measurement for the further capacitive sensor.
6. A system configured to provide grip detection of a handheld device comprising:
a left capacitive sensor configured to provide capacitance measurements related to a first portion of a hand adjacent to the left side of handheld device;
a right capacitive sensor configured to provide capacitance measurements related to a second portion of the hand adjacent to the right side of handheld device;
one or more memories for storing the capacitive sensor measurements;
one or more processors operable to execute instructions based on the capacitive sensor measurements, the instructions comprising:
receiving capacitance measurements measured by at least two capacitive sensors of the handheld device, including: (1) the left capacitive sensor configured to provide capacitance measurements related to a first portion of a hand adjacent to the left side of handheld device and (2) the right capacitive sensor configured to provide capacitance measurements related to a second portion of the hand adjacent to the right side of handheld device;
calculating a magnitude of the differential capacitance measurement between the left capacitive sensor and the right capacitive sensor;
calculating a sum of (1) the single-ended capacitance measurement of the left capacitive sensor, and (2) the single-ended capacitance measurement of the right capacitive sensor;
applying a predetermined algorithm to one of more of the capacitive measurements or calculated thereof;
determining a type of grip of the hand on the handheld device based on the capacitance measurements and algorithm application thereto, wherein the capacitance measurements include a differential capacitance measurement between the left capacitive sensor and the right capacitive sensor, a single-ended capacitance measurement of the left capacitive sensor, and a single-ended capacitance measurement of the right capacitive sensor;
wherein, the type of grip specifies placements of the palm, digits, and thumb on the handheld device in a particular configuration.
7. The system of claim 6 , wherein:
the left capacitive sensor is located on or positioned along the left side of the handheld device; and
the right capacitive sensor is located on or positioned along the right side of the handheld device.
8. The system of claim 6 , wherein:
the left capacitive sensor faces a left face of the handheld device; and
the right capacitive sensor faces a right face of the handheld device.
9. The system of claim 6 , wherein:
the left capacitive sensor and the right capacitive sensor are parallel to front and back faces of the handheld device and proximate to a back face of the handheld device.
10. The system of claim 6 , wherein the system is configured such that the first capacitive sensor is connected to a positive input of a differential amplifier front-end to an analog-to-digital converter and the second capacitive sensor to a negative input of the differential amplifier front-end, or vice versa, to obtain the differential capacitance measurement between the first capacitive sensor and the second capacitive sensor.
11. The system of claim 6 wherein, the left capacitive sensor and the right capacitive sensor each has a width between 1-4 mm.
12. The system of claim 6 , further comprising:
a switch matrix for iterating through different capacitance readings, including connecting the left capacitive sensor to a positive input of a differential amplifier front-end to an analog-to-digital converter and the right capacitive sensor to a negative input of the differential amplifier front-end, or vice versa to obtain the differential capacitance measurement between the left capacitive sensor and the right capacitive sensor.
13. The system of claim 12 , wherein the switch matrix is further configured to:
connect the left capacitive sensor to the analog-to-digital converter for the single-ended capacitance measurement of the left capacitive sensor and connecting the right capacitive sensor to the analog-to-digital converter for the single-ended capacitance measurement of the right capacitive sensor.
14. The system of claim 6 , further comprising:
a bias sensor that is electrostatically shielded, includes the same material used in a housing of the handheld device and exposed to the same environment as the housing with respect to temperature and/or humidity.
15. The system of claim 14 wherein, the bias sensor is connectable by a switch matrix in a differential measurement configuration with the left capacitive sensor or the right capacitive sensor to detect connection breakage and/or manufacturing defects.
16. The system of claim 6 further comprising:
a further capacitive sensor;
wherein, the type of grip of the hand on the handheld device is determined based further on one or more of: (1) a differential capacitance measurement between the left capacitive sensor and the further capacitive sensor, (2) a differential capacitance measurement between the right capacitive sensor and the further capacitive sensor, (3) and a single-ended capacitance measurement for the further capacitive sensor.