May 2009

Doc ID 15601 Rev 1

1/9

AN2967

Application note

Implementing a driven shield

on STM8T and STM8TS capacitive sensors

Introduction

The STM8T and STM8TS capacitive sensors opens up a new dimension to capacitive

sensing by detecting user’s proximity up to 30 cm. This is a key feature for many end-

applications such as personal navigation devices (PNDs) or stove tops which are equipped

with backlighting that switches on when a user is detected. Proximity detectors are also

implemented in white goods, automotive devices, palm tops, and on any type of kitchen or

office appliance where the display needs to be turned on to allow some parameters to be

adjusted by the user.

To enhance their application appearance and ease-of-use, designers can choose to add

proximity detection as an extra feature. The alternative is to implement it to save energy,

allowing the product to remain in sleep mode and only wake up when it detects a user in its

proximity.

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