glove-operation validation guide<\/a>.<\/p>\nDo not place an overlay over an existing touch switch as an informal experiment if that could damage the product seal, label, surface finish, or mounting. Use a sample assembly or an approved test fixture. An overlay can also alter cleaning, visibility, abrasion, ingress protection, and operator accessibility, which must be evaluated separately from sensing performance.<\/p>\nValidate the exact overlay material, thickness, gap, panel, and sensor before specifying through-cover operation.<\/figcaption><\/figure>\nA repeatable overlay validation process<\/h2>\n First define the required touch target and who will use it. Record the minimum reliable finger area, operating posture, approach direction, glove requirements, and whether the user can touch anywhere on the panel or only a marked area. A sensor that triggers on a large bare fingertip may fail with a small glove-covered fingertip.<\/p>\n
Build a test stack that matches production: actual overlay lot and thickness, coating or printed graphics, adhesive, air gap, gasket, panel, frame, and mounting hardware. Include tolerance extremes and realistic temperature or humidity conditions if the product will encounter them. Do not use a thick transparent plate as a stand-in for a production window unless its material and dimensions are confirmed.<\/p>\n
Establish a baseline and detection criterion using the controller\u2019s approved process. Record the raw or reported signal when untouched, during a deliberate touch, during a near approach, and when a hand passes nearby. Check for false detection from vibration, a wet cleaning cloth if relevant, switching loads, cable movement, and adjacent controls. Repeat after power-up and after the enclosure is grounded and fully assembled.<\/p>\n
If performance is marginal, do not simply increase sensitivity. Ask the controller manufacturer which electrode geometry, tuning, shielding, or filtering parameters are supported. A change can increase noise susceptibility or cause the touch to remain latched. Re-run the full test matrix after every change and document the revision that passed.<\/p>\nA bench result applies only to the tested sensor and assembly; it is not a universal thickness rating.<\/figcaption><\/figure>\nWhen evaluating a commercial touch assembly, send the supplier the exact product code and a drawing or sample of the complete panel stack. Include overlay material and grade, minimum\/nominal\/maximum thickness, coatings and printing, adhesive, air gap, nearby grounded metal, cable length, controller model, operating supply, and required bare-finger or glove behavior. Ask whether that exact combination is supported, what test conditions were used, and whether the resulting output is a touch signal, relay contact, or another interface.<\/p>\n
If the supplier cannot confirm the stack-up, use a non-production evaluation fixture and agree acceptance criteria before testing. Record successful touches and false activations, then repeat the test after the enclosure and electrical installation are complete. Do not convert a one-off demonstration into an environmental or safety claim.<\/p>\n
Common mistakes when specifying touch through glass or plastic<\/h2>\n The most common error is copying a maximum thickness from another vendor\u2019s reference design. That result belongs to the specific controller, electrode, glass, air gap, firmware, and test procedure used in that project. It should not be presented as an industry-wide limit or as ONPOW product data.<\/p>\n
Another error is testing only clear, uncoated glass and then releasing a tinted or printed production panel. Paint, conductive coatings, metal trim, adhesives, and decorative layers can change coupling. Likewise, the sample may be thin at its center but thicker at its edge, or production tolerances may enlarge an air gap.<\/p>\n
Designers also sometimes treat a successful touch as proof that the interface is suitable for a machine command. Touch detection and the machine\u2019s response are separate. The application still needs appropriate logic, feedback, fault behavior, access control, and safety validation. See ONPOW\u2019s capacitive and piezoelectric switch comparison<\/a> and touch switch versus push button guide<\/a> for the broader interface decision.<\/p>\nFrequently asked questions<\/h2>\nCan capacitive touch work through glass?<\/h3>\n Yes, in a design engineered and validated for the selected sensor and glass assembly. Performance depends on thickness, spacing, electrode geometry, controller settings, and the real enclosure; it is not guaranteed for every touch switch.<\/p>\n
Can capacitive touch work through plastic?<\/h3>\n It can, depending on the plastic formulation, thickness, coating, gap, sensor design, and controller. Test the exact production material and stack-up rather than relying on the generic word \u201cplastic.\u201d<\/p>\n
Does a 10 mm example mean any sensor works through 10 mm glass?<\/h3>\n No. TI reports that performance for its TIDA-00343 reference design and its defined configuration. It is an example, not a universal limit or ONPOW specification.<\/p>\n
Do not assume so. Confirm the exact product construction and intended installation with its current documentation or ONPOW, then test the assembled panel if an overlay is required.<\/p>\n
What should be tested before production?<\/h3>\n Test the actual overlay material, thickness tolerance, finish, air gap, frame, grounding, sensor settings, bare-finger and required-glove use, nearby interference, startup, and final enclosure configuration.<\/p>\n
Educational video<\/h2>\n This Texas Instruments reference-design video demonstrates touch input through a defined glass window. Its performance belongs to that TI design and does not establish a thickness or through-cover rating for ONPOW products.<\/p>\n