Vehicle Rain Sensor Temperature Compensation Circuit
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Solution Overview
Problem
Optical sensors, such as rain sensors in vehicles, experience sensitivity fluctuations due to temperature changes, affecting their accuracy in detecting light and rainfall.
Innovation Solution
Incorporating a temperature compensation circuit with a thermistor and a microcontroller that adjusts the current supplied to the light emitting device to maintain constant light intensity regardless of temperature changes, ensuring consistent sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the optical sensor operates based on light amount received by the light receiving device, then distance measurement and object detection functions are achieved, but the sensor becomes sensitive to temperature changes causing malfunction
Solution Approach 1:
A temperature sensor is introduced as an intermediary element to detect temperature changes and provide data to the microcontroller. This mediator allows the system to compensate for temperature effects on the light emitting device, resolving the contradiction between maintaining reliable operation and eliminating temperature sensitivity.
Solution Approach 2:
The microcontroller dynamically adjusts the driving current parameter supplied to the light emitting device based on temperature sensor readings. By changing this electrical parameter in response to temperature variations, the system maintains constant light emission intensity despite temperature changes, thereby eliminating temperature sensitivity while preserving reliable operation.
2Productivity
If the light emitting device emits light for distance measurement and object detection, then the optical sensor performs its primary function, but the emission amount of light changes with temperature
Solution Approach 1:
The system implements a feedback loop where the temperature sensor continuously monitors temperature changes, the microcontroller processes this information, and adjusts the driving current to the light emitting device accordingly. This closed-loop feedback mechanism ensures stable light emission intensity while maintaining the productivity of distance measurement and object detection functions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution maintains consistent sensitivity and accuracy of optical sensors across varying temperatures, preventing malfunctions and ensuring reliable operation in temperature-sensitive environments.
Implementation Method 1
a temperature sensor coupled with the light emitting device, and having electrical resistance varying with temperature
Implementation Method 2
a light receiving device configured to receive the light emitted from the light emitting device, and to output current based on an intensity of the received light
Data Source
AI summary
The present disclosure provides an optical sensor having constant sensitivity regardless of changes in temperature. The optical sensor may include a light emitting device configured to emit light; a light receiving device configured to receive the light emitted from the light emitting device, and to output current based on an intensity of the light; a temperature sensor coupled with the light emitting device, and having electrical resistance varying with temperature; and a microcontroller including a first channel for supplying first current directly to the light emitting device, a second channel for supplying second current to the light emitting device via the temperature sensor, and a third channel for receiving the current output from the light receiving device.