Using Hall-effect sensing to detect the rotation of a magnet, Azoteq of South Africa calls its Digital Crown its crowning achievement. For more than twenty years, the fabless semiconductor company has been boldly enabling new applications for electronic devices, many of them employing sophisticated magnetic sensing technology. The Digital Crown can be used to design a contactless and waterproof solution for many applications.
Azoteq’s technology allows for the designing of various dustproof and waterproof user interfaces based on contactless inductive sensing. A small deflection or change in distance, from a metal target can be detected by an inductive sensing coil that is sealed inside the housing of its waterproof button. Hermetically sealed against dust and water, applications for the technology are numerous. It can be used to design a contactless magnetic crown for a smartwatch, to handle precise rotation for volume adjustment or for a waterproof knob on a kitchen appliance.
The highly flexible IQS624 IC has multiple sensing capabilities including Hall-effect rotation sensing, along with dual-channel capactive proximity and touch sensing, or single-channel inductive sensing. The two Hall-effect sensors calculate the angle of a magnet rotating parallel with the sensor. The sensor is fully I2C compatible and on-chip calculations enable the IC to stream the current angle of the magnet without extra calculations.
There are two internal Hall-effect sensing plates on die, so no external sensing hardware is required for Hall-effect sensing. The Hall-effect sensor measures the generated voltage difference across the plate, which can be modelled as a Wheatstone bridge. The voltage difference is converted to a current using an operational amplifier in order to be measured by the same ProxSense sensor engine.
It is among numerous ICs that Azoteq makes for rotation and other sensing needs. The company’s ProxFusion IQS7210 IC is a sensor fusion device targeting the wearable fitness market. A low-power dedicated wake-up touch button launches full trackpad and touchscreen sensing for up to 42 channels, integrated with wear detect, force touch and Hall sensing capabilities.
Founded in 1998 by Frederick Bruwer, a pioneer in remote keyless entry technology, Azoteq initially developed the LightSense range intelligent drivers for flashlights and headlamps and has since introduced other products for lighting, as well as for touch and proximity sensing. The ProxFusion product line for multi-sensing on a single chip is its latest addition.
The CTO of the company is Dieter Mellet, one of the original inventors of ProxSense and ProxFusion technologies. For more info, see www.azoteq.com.