MSP CapTIvate Moisture rejection (wrong touch)

Kummi

Other Parts Discussed in Thread: CAPTIVATE-PHONE

Hi,

We are promoting MSP CapTIvate for our customer application which needs
moisture resistive solution.

We tried to spill some water on the CapTIvate EVM(CapTIvate Phone) to create
the moisture environment, but if the water stays between two or more touch key pads,
we get multiple touches for a single touch.

As shown below the water stays on some key pads and if we touch key pad "8"
the MSP recognizes more than 3 key pads(8,9,#) instead of only "8".
Is there any way to avoid multiple key touch for a single touch?
Is this avoidable with a guard channel? and please let me know the procedure
the settings necessary.

Best Regards
Kummi

over 9 years ago

0 Mike Pridgen over 9 years ago

TI__Mastermind 22685 points

Hi Kummi,

If you take a look at the CapTIvate Technology Guide, under Design Guide -> Moisture -> Moisture Mitigation Techniques, it explains the recommended strategy to mitigate moisture detection. Effectively, what you do is implement software if the guard channel is touched, it ignores all other sensors (regardless of whether they report touch or no-touch).

Mike

0 Kummi over 9 years ago in reply to Mike Pridgen

Mastermind 6220 points

Hi Mike,

Thank you so much for the quick reply
and I am sorry for the delay.

As you mentioned "implement software if the guard channel is touched, it ignores all other sensors"
if possible could you please provide us the sample code or reference code on how to do this.

Best Regards
Kummi

0 Mike Pridgen over 9 years ago in reply to Kummi

TI__Mastermind 22685 points

Hi Kummi,

Please take a look at the CAPTIVATE-PHONE demo that comes with the CapTIvate kit. That board has a guard channel, and I believe the project contains an example of how to use a guard channel.

Mike

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MSP CapTIvate Moisture rejection (wrong touch)