Problem with capacitive touch sensing using TTP223/TTP233

[kian0079]

Hi all,

I am working on a project which requires reliable and fast response to touch sensing. A physical button is not feasible for my application as I require to sense light touches on a flat surface (diameter of 20mm). My current solution uses the very popular TTP223/TTP233 capacitive touch IC. However, its seems to have a fairly slow response time as I am unable to sense multiple touches within 1 second. It works if I touch every approximately 0.5 seconds. But anything faster, it doesn't capture a touch. I have the output of the TTP233 connected to an interrupt pin of a microcontroller which prints out a serial message when touch. I don't think the lag is caused by the microcontroller side since its just a simple program that doesn't do anything other than waits for the interrupt to trigger. Does anyone who used the TTP223/TTP233 before encountered the same problem? If so, how did you overcome the slow response problem?

Otherwise are there other alternative solutions (that are more responsive and reliable) that anyone can recommend?