Skip to main content

Upgrade Mechanical Interfaces with Minimal Work

title

The popularity of smart devices, with the likes of Angry Birds, texting and selfies, have also provided users with powerful, yet simple to use interfaces and experiences. More and more, these interfaces are now expected to be deployed in all manner of devices.  Yet, while not all devices need this level of sophistication, many can take advange of touch interfaces that provide a pleasent user experience without the use of knobs, switches and buttons which can introduce reliability, power and aestheic issues into the product design.

For the designer, there are two common hurdles to implement a good interface experience. First, many developers are comfortable with simple connections like switches and buttons requiring minimal software expertise.  Second, there can be many complexities with touch designs such as layout, crosstalk, moisture sensitivity, and panel thickness.  So, what if there is a way to reduce these "headaches"?

Enter Silicon Labs TouchXpress Series of capacitive touch controllers.  These devices allow one to add capacitive touch to any system via a simple GPIO or I2C Interface.  No complicated requirements to scan, sense and process the inputs.  All of this is done inside of the device.  So what does the designer have to do?  Mostly, this is just basic configuration of the device which is done through the all-in-one Silicon Labs development environment, Simplicity Studio.  Let's focus on two aspects: Xpress Configurator and Capacitive Sense Profiler.

Xpress Configurator lets the developer easily set device parameters such as scan period, sleep time, drive strength and sense thresholds.  The picture below shows an example for the CPT007B, 7 channel device.  Simply enter the desired values and the device registers are programmed according.

title

Once the configurations are set, the Capacitive Sense Profiler can be used to view the performance of the system  Here, the developer can graphically see the touch activity and analyze performance.  For example, perhaps the thresholds need to be adjusted.  The picture below, shows the results of button pushes using the CPT112S, 12 channel evaluation kit.  Note that the data shows when the thresholds are reached resulting in a push/no push indication.

title

With simple analysis the designer is now able to evaluate performance, tweak and program these devices for the end product.  The following table summarize the key features of both the 7 and 12 channel devices.

title

For more information, please see:

 

Click for CPT007B  and Evaluation board

Click for CPT112S and Evaluation board

rdruian has not written a bio yet…
DesignSpark Electrical Logolinkedin