Museums are typically in need of many visitor interface devices.  Many times it is just a push button.   Usually the designer requires that the button provide feedback or at least be lit when the system is on.  In our experiences, the HAPP (now Suzo-Happ) button is the device most used on museum reader rails.   We got a request to price a large capacitive switch that provided visual feedback.  After giving our estimate, we decided to pursue this idea with a prototype because we envision this might be a product that sets off an otherwise ordinary interactive exhibit.  From the prototype, we have derived a production unit.

Here are some specifics.  The capacitive electrode (read switch) is 1.75 inches by 2.125 inches in size.  We have a version that can stand alone (i.e. does not provide feedback) and one that plugs into a feedback circuit card.  The feedback circuit card provides a 5 x 7 LED matrix for the feedback to be displayed on.  This allows shape changing feedback (like an on and off button) or an alphanumeric.  The feedback circuit can generate its own feedback from button presses.  It can also provide a TTL signal to another controller or processor and get cues from the processor on which character to show on its display via six inputs.  Click on the image right above to view pictures of this product in its various configurations.

Capacitive switches are very prone to external conditions in their environment, but the chip we are using has drastically reduced these effects.  It does need to be tuned for the following specifics in the exhibit it will be used:  the size of the electrode (read switch), the dielectric and thickness of the material between the electrode and the user, and the amount of body surface the user needs to apply for actuation (pinky finger or entire hand).  So far we have been able to tune our current electrode version ( 1.75”x 2.125” with 35 drilled holes) for a child’s finger on plexi-glass up to 0.5 inches thick and under pine wood up to 5/8” thick.  Obviously, the pine wood did not take advantage of the feedback capability.  We look forward to exploring your requirements for capacitive touch switches in exhibit/kiosk applications.  We have two short videos demonstrating our prototype which has a one quarter inch thick plexi cover:

Pricing

• Touch Commander (Stand-alone) $85
• Touch Commander with simple feedback $350
• Additional Touch Cmdr Feedback Development Call