Uneven mating surfaces, floating height requirements, and
exposure to extreme vibration all challenge the integrity of
electrical connections. Field proven for performance and
reliability in harsh environments, Mill-Max spring-loaded
contacts ensure continuity across a wide variety of length
and stroke configurations, including new low and ultra-low
Don’t see what you need? Rapid prototyping
and custom designs are our specialty.
CONSISTENT AND RELIABLE
MillMaxMfg Mill-Max Mfg. Corp.
By Steve Sheard, ON Semiconductor
Specifying touch switches as an alternative to conventional elec- tro-mechanical devices, such as pushbuttons, toggles, or membrane switches, is becoming increasingly commonplace in modern system designs within domestic, office, medical, and industrial spheres.
The choice is between two core technologies when implementing touch
switches, self capacitive or mutual capacitive sensing.
In recent years, engineer’s approach to user interface development has
radically changed. Touch-based sensor mechanisms now make up the
vast majority of human-machine interfaces within the consumer portable
electronics sector, as well as an ongoing proliferation into various other
sectors. Among the products in which touch switches are starting to
bring multiple operational benefits are white goods, cooking appliances,
printers, PCs, game consoles, and vehicle infotainment systems. With this
technology, OEMs are presented with a higher degree of design freedom.
They can also develop products with strong appeal to consumers thanks
to greater durability (resulting in longer operational lifespans), more
aesthetically-pleasing external appearance, resilience against the environmental conditions to which they are subjected (waterproofing and ability
to endure high temperatures, etc.), as well as the relative ease of keeping
them clean. As engineers begin to grasp a better understanding about the
key elements affecting touch switch technology, more effective product
designs will be achieved and the quality of user interaction.
Self and mutual capacitive sensing
In reality, the majority of mutual capacitive sensing solutions are only
a single detection, self-sensing implementation applied to 8 x 8 wire
Figure 1: Comparison between self and mutual differential sensing (All
images credited to OnSemi)