New products have been released by Melexis that support the use of robust optical proximity and gesture detection systems in automotive environments.
In automotive applications, optical proximity and gesture detection works to enable a more intuitive HMI experience. The company advises that typical challenges for such systems are cost, sunlight robustness, electro-magnetic interference and mechanical integration constraints, while supporting multiple OEM configurations.
In response the company has developedoptical gesture and proximity sensing ICs in the form of the MLX75030 and MLX75031 to address these challenges. These devices integrate ambient light suppression technology developed by the company.
The ICs feature two simultaneously operating light measurement channels which can detect the active optical reflection from a target. Ambient light suppression makes these channels highly tolerant to background light interference. Two additional channels are available to measure ambient light.
On system level, the ICs should be complemented by one or two LEDs and photodiodes, of any type, for active light detection. The MLX75030 allows external switches to drive the LEDs up to 1 A peak current, while the MLX75031 integrates the LED drivers to minimise external component count.
Ambient light can be detected with up to two independent photodiodes. Any amount of detection channels can be added through multiplexing. Internal control logic, configurable user registers and SPI communication enable intuitive, programmable operation. Additional circuit functions like a watchdog timer, on-board temperature sensor and self-diagnostics are built-in to facilitate robust product design.
The digital output from the ICs contain the measured active light and ambient light levels, which should be processed on the customer’s microcontroller to detect gestures such as swipe, zoom or scroll. A measurement rate of up to 700Hz per measurement channel allows smooth interface response times.
Addressing space constrains, the ICs measure 4mm by 4mm), in a 24-pin surface mount QFN package. Both devices have been AEC-Q100 qualified for – 40°C to 105°C operational temperature range.