Most capacitive touch screens are pre-configured to work with their mated display–the calibration information stored in the IC–so that end-user calibration is not necessary. Typically you read of a bank of registers on the IC, one register contains the number of points touched, and others registers follow with X and Y coordinate pairs of each point.Ī resistive touch screen will need to be calibrated, at least once, before shipping to the customer. While this IC increases the cost of the touch screen, it can make communication easier by using the I2C interface. Projected Capacitance takes orders of magnitude more finesse to read it, and so most capacitive touch screens have a dedicated IC bonded to their flexible printed circuit ( FPC) to handle the added complexity. Typically this interface adds zero incremental cost to the project.Ī capacitive touch screen uses something called Projected Capacitance to detect your finger. The interface to a resistive touch screen is typically accomplished with two digital ports and two analog ports of your microcontroller, along with a few lines of code. Resistive touch screens are still lower cost, but the gap is shrinking The glass of a capacitive touch screen is optically flat, allowing the display to be seen very clearly.Ī resistive touch screen typically has a slight “anti-glare” texture to the surface that can slightly blur the display. To be fair, the display just behind a resistive touch screen is typically also glass, so an impact can damage a resistive touch screen as well.Ī capacitive touch screen blocks less light than a resistive touch screen, allowing more light to pass through. While these are rugged, they can be scratched and become foggy with use.Ī capacitive touch screen’s outer layer is glass and is therefore quite abrasion resistant - though glass is subject to breaking under impact. but non-conductive objects like a gloved finger or the plastic handle of a screwdriver will not be detected.Ī resistive touch screen only depends on force, it does not care what is creating the force.Ī resistive touch screen is composed using thin, tough plastic membranes. Your finger works well, or the end of a wrench you are holding. Two or more simultaneous touch points allow the popular “pinch” moves to zoomĪ capacitive touch screen depends on a conductive contact. There are many other differences between a resistive and a capacitive touch screens– let’s compare some touch screen properties, and how they are different between resistive touch screens and capacitive touch screens.
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