Rotary knob switch with a display in the middle

Anders has introduced a family of rotary switches that have a circular colour TFT-LCD in the middle, as well as a push button function.

Available with 1.3, 2.1 or 2.47inch circular displays, the knobs are ~48, 76 or 92mm in diameter respectively.

The company sees them being used in heating systems, industrial controls, IoT devices, boilers, white goods, fitness equipment and audio equipment.

"The switch available in each display size permits convenient and intuitive adjustments such as temperature, volume, motor speed, timer settings, lighting, dimming and ambience control settings," it said, explaining "The switch is operated by turning a perimeter ring, which provides a tactile response to confirm the selection and hold the switch in position."

Picking the 2.1inch version as an example, the 78.4mm diameter 17mm tall knob dominates the module, while the electronics and mount create a smaller rear protrusion that brings total height to 25mm.

Its display, which stays still while the knob rotates around it, is 480 pixels and 53mm across (which is where the ‘2.1inch’ comes from), and uses IPS technology for a near-hemispherical viewing angle. Nominal brightness is 210cd/m2. The switch offers continuous rotation through 30 positions per revolution.

Operation is from 4.5 to 7V (5V nominal) and consumption is 150 – 350mA.

It is available with either UART or MIPI interface, as is the larger knob, while the smaller one also has a UART option, but the MIPI option is dropped in favour of an SPI interface.

Electronics Weekly has asked of the rotary encoder output is via the serial link – the data sheet is vague on this, and also hints of a push-button action – watch this space.

Anders replies:

Yes, the push button is built in and part of the structure.For the versions with SPI and MIPI interfaces, there is a pin for the push button.For versions with UART interface, pressed button events are handle by the sub-system, i.e. the microcontroller which processes events over the UART interface which are then communicated to the LCD module

"Circular displays represent an opportunity to grab customers’ attention and create an almost infinite range of imaginative effects," said Anders. "Examples include making a timer count up or down by illuminating or turning off graduations around the edge, darkening or brightening the display as the user adjusts a lighting dimmer, or changing the back light colour of a heating or air-conditioning controller depending on the user's setting."

The company has an in-house engineering team to support part choice, user-interface design and software development.

Scheduled for later this year is a radial graphics evaluation kit that includes a microcontroller board and software libraries.

Find the 2.1inch version on this Anders web page, the others are a single click from there. Take a look at the videos to see what a nice user interface the parts can offer.

Photos: which size of knob-display is in each photo is not specified