# US 2026/0063548 A1 · Noise suppression using multiple light sensors in a photoelectric smoke detector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2026/0063548 A1 - Document ID: US20260063548A1 - Status: Published application - Kind: A1 - Application number: 18/941,100 - Filed: 2024-11-08 - Published: 2026-03-05 - Earliest claimed: 2024-09-04 - Assignees: Microchip Technology Incorporated - Applicants: Microchip Technology Incorporated - Inventors: Patrick McFarland; Arthur B. Eck; Jonathan Corbett; Robert Perkel - Web page: https://patentgrep.com/patent/US20260063548A1 ## CPC - G01N 21/53: within a flowing fluid, e.g. smoke - G01N 2201/121: Correction signals - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract A system and method for the use of digital analysis to filter out extraneous light are disclosed. The system may include a light source to emit a light beam in a smoke detector. The system may include a first light sensor in the smoke detector to receive a reflected light beam corresponding to the light beam reflecting off a smoke particle. The system may include a second light sensor in the smoke detector to receive a noise light corresponding to ambient light in the smoke detector. The system may include a control circuit. The control circuit may be to receive the reflected light signal from a first light sensor indicative of the reflected light beam and to receive a noise signal from the second light sensor indicative of the noise light. The control circuit may be to reduce noise from the reflected light signal based on the noise signal. ## Claims ### Claim 1 An apparatus, comprising: a first light sensor interface communicatively coupled to a first light sensor in a smoke detector; a second light sensor interface communicatively coupled to a second light sensor in the smoke detector; a control circuit communicatively coupled to the first light sensor interface and the second light sensor interface, the control circuit to: receive a reflected light signal from the first light sensor via the first light sensor interface; receive a noise signal from the second light sensor via the second light sensor interface; and reduce noise from the reflected light signal based on the noise signal. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the control circuit is to reduce the noise from the reflected light signal by subtracting the noise signal from the reflected light signal. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the second light sensor is substantially aligned with a source of the noise signal. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the second light sensor is positioned such that the reflected light signal is outside a field of view of the second light sensor. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the first light sensor and the second light sensor are substantially aligned. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the control circuit is to process the noise signal using at least one of a Weiner filter or a Kalman filter to improve a signal-to-noise ratio of the noise signal. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the control circuit is to integrate the noise signal over time to increase a signal-to-noise ratio of the noise signal. ### Claim 8 A method, comprising: receiving a reflected light signal from a first light sensor in a smoke detector; receiving a noise signal from a second light sensor in the smoke detector; and reducing noise from the reflected light signal based on the noise signal. ### Claim 9 (depends on 8) The method of claim 8, wherein reducing the noise from the reflected light signal includes subtracting the noise signal from the reflected light signal. ### Claim 10 (depends on 8) The method of claim 8, wherein the second light sensor is substantially aligned with a source of the noise signal. ### Claim 11 (depends on 8) The method of claim 8, wherein the second light sensor is positioned such that the reflected light signal is outside a field of view of the second light sensor. ### Claim 12 (depends on 8) The method of claim 8, wherein the first light sensor and the second light sensor are substantially aligned. ### Claim 13 (depends on 8) The method of claim 8, comprising processing the noise signal using at least one of a Weiner filter or a Kalman filter to improve a signal-to-noise ratio of the noise signal. ### Claim 14 A system, comprising: a light source to emit a light beam in a smoke detector; a first light sensor in the smoke detector to receive a reflected light beam corresponding to the light beam reflecting off a smoke particle; a second light sensor in the smoke detector to receive a noise light corresponding to ambient light in the smoke detector; and a control circuit to: receive a reflected light signal from the first light sensor indicative of the reflected light beam; receive a noise signal from the second light sensor indicative of the noise light; and reduce noise from the reflected light signal based on the noise signal. ### Claim 15 (depends on 14) The system of claim 14, wherein the control circuit is to reduce noise from the reflected light signal by subtracting the noise signal from the reflected light signal. ### Claim 16 (depends on 14) The system of claim 14, wherein the second light sensor is substantially aligned with a source of the noise signal. ### Claim 17 (depends on 14) The system of claim 14, wherein the second light sensor is positioned such that the reflected light signal is outside a field of view of the second light sensor. ### Claim 18 (depends on 14) The system of claim 14, wherein the first light sensor and the second light sensor are substantially aligned. ### Claim 19 (depends on 14) The system of claim 14, wherein the control circuit is to process the noise signal using at least one of a Weiner filter or a Kalman filter to improve a signal-to-noise ratio of the noise signal. ### Claim 20 (depends on 14) The system of claim 14, wherein the control circuit is to integrate the noise signal over time to increase a signal-to-noise ratio of the noise signal.