topic MPR121 disable baseline filtering ?! in Sensors

MPR121 disable baseline filtering ?!

felixover — Mon, 18 May 2015 09:42:19 GMT

Hello,

in my scenario i want to use the MPR121 for LONG time touch/body detection. The Problem is that the baseline-filter decreases my baseline-value an after a few minutes and the body will not be detected anymore. My Thresholds are 10 for touch and 5 for release so when the filter decreases the value for 4 (is this configurable ? its always 4 even if i change NHDL and NHDT) the baseline - filtered value is not < threshold anymore

The solution to set the NCL and FDL both to 0xFF only create a delay but will not solve the problem.

Is it possible to deactivate the filter ? Or set the value which decreases the baseline to zero ?

Re: MPR121 disable baseline filtering ?!

reyes — Wed, 27 May 2015 16:44:23 GMT

Hi Felix Over,

You can disable the baseline tracking by setting CL bit on Register 0x5E to [01] as can be seen on page 16 of the MPR121 Datasheet.

Other thing you can do is to change the filters configuration. Check the Application Note AN3891 for filters configuration information.

Have a great day,
Jose Reyes

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