3 Design Considerations for Magnetic Dials

Building a dial or rotary encoder for an HMI application does not require a high sample rate. The slower sample rate enables Hall-effect devices to use low-power features such as sleep or wakeup modes or integrate averaging of the data to achieve a higher signal-to-noise ratio. When designing a dial using Hall-effect sensors, mechanical feedback can be implemented through haptic feedback or including notches in the mechanical design.

Altering the mechanical design of the dial to provide mechanical feedback can enable an implementation that snaps to certain areas of the rotational range or avoids in-between states, when designing something such as a function selector. Because the mechanical implementation is no longer involved in the rotational sensing, any wear and tear on the mechanical aspect of the dial will not impact the rotational sensing performance. While there may be some degradation in the feel of the dial, having a reliable sensing implementation still enables the product to continue working longer without the need for repair or replacement.