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Overview for Capacitive Sensing
Capacitive sensing is a high resolution, low cost, contactless sensing technique that can be applied to a variety of applications such as liquid level sensing, proximity sensing, gesture recognition, ice/rain detection, and collision avoidance.
The sensor in a capacitive sensing system is any conductor, such as copper on PCB, conductive ink, or a piece of metal, allowing for low-cost and highly-flexible system design. This conductor acts as a proximity sensor or liquid level sensor depending on the use case.
Getting started with capacitive sensing
Key benefits of TI capacitive sensing technology
- TI's out of phase level sensing is unique in the industry and minimizes the impact of external interferers such as human hands that introduce measurement errors in capacitance sensing systems
- Large input offset allows compensation of environmental variables such as temperature and humidity in addition to allowing remote sensing capabilities
- Large shield drive minimizes EMI interference, focuses sensing direction, and reduces the effects of humidity and temperature changes
- High resolution allows for distance object sensing with a small, inexpensive conductive sensor
Highlights of capacitive sensing technology
- Strong reliability: Offers contactless sensing that eliminates mechanical wear
- Great flexibility: Sensor size and shape can adapt to system geometry
- Low system cost: Uses low cost sensors, either a piece of metal already existing in the system or a small, two-layer copper on PCB or a pressed foil or a copper tape or a conductive ink
- High sensitivity: Sensitive to both conductive and non-conductive materials
- Basics of capacitance sensing and applications (PDF, 390KB)
- Capacitive sensing: Ins and outs of active shielding (PDF, 940KB)
Using capacitive sensing for liquid level sensing
Capacitive sensing has gained popularity as a liquid level sensor due to the accuracy and resolution of the measurements as well as the simplicity, flexibility, and low cost of the sensor design.
- Capacitive-based liquid level sensing
- Out-of-phase liquid level technique (PDF, 600KB)
- Ice buildup detection using TI's capacitive sensor (PDF, 4.9MB
Using capacitive sensing for proximity sensing Capacitive sensing can be used as a low cost, flexible solution for a number of proximity sensing applications such as proximity wakeup in thermostats, appliances, and consumer goods; collision avoidance in industrial and automotive doors; and kick sensors and keyless entry in automotive doors.
Capacitive-based human proximity detection for system wake-up & interruptBacklight and Smart lighting control by ambient light and proximity
Automotive Capacitive Proximity Kick to Open Detection