Proximity 9 Click is a very accurate and reliable proximity sensing (PS) and ambient light sensing (ALS) device, equipped with the VCNL4040, an integrated PS and ALS sensor which features the Filtron™ technology. The 940nm IRED emitter, along with the low noise analog front end, and the PS/ALS photo-sensitive elements, is integrated on the VCNL4040 IC, ensuring very accurate and reliable measurements. The proprietary Filtron™ technology provides response near to the human eye spectral response, providing the background light cancellation. The programmable interrupt engine allows for the development of an optimized firmware, reducing the MCU workload and power consumption.
Proximity 9 Click is supported by a mikroSDK compliant library, which includes functions that simplify software development.
The VCNL4040 also integrates some additional features for better reliability. It has an intelligent crosstalk cancelation scheme implemented, in order to reduce the crosstalk phenomenon. A smart persistence allows the interrupt engine to avoid false interrupt triggering. Rich with features, this Click board™ can be used for a range of different applications which rely on the accurate and reliable close proximity and ambient light sensing, including PC and laptop displays, POS displays, embedded displays, proximity-activated short-range security, lux meters, etc.
Proximity 9 Click features the VCNL4040, a fully integrated proximity and ambient light sensor with I2C interface, from Vishay Semiconductors. It is an advanced 16bit Ambient Light Sensor (ALS) which makes use of the proprietary Filtron™ technology, providing spectral response near to a human eye. The ALS sensor also helps with the flickering of fluorescent light sources, and background light cancellation, reducing the workload of the host MCU. This sensor features a 940 nm IRED on-chip, driven by a programmable current sink driver. The VCNL4040 is also thermally compensated, allowing very accurate readings within the range between -40⁰C and +85⁰C.
The Proximity Sensing (PS) section of the VCNL4040 IC implements several solutions for the improved proximity detection of objects of any color. It relies on the detection of the reflected IR light from the IRED emitter. Features such as the immunity to a red glow, intelligent crosstalk phenomenon reduction, smart persistence scheme for false interrupt triggering prevention, programmable IRED current, selectable sampling resolution, and selectable integration time, help achieving a reliable and accurate proximity detection. The processed readings of the ALS and PS sensors can be fetched from the respective registers via the I2C interface. The I2C bus lines are routed to the respective mikroBUS™ I2C pins: SCL is the I2C clock and SDA is the I2C data line.
Proximity 9 Click offers programmable interrupt engine. The INT pin is routed to the mikroBUS™ INT pin and it is pulled up by the onboard resistor. When asserted, it is driven to a LOW logic level. The interrupt can be programmed to be triggered whenever PS threshold window is exceeded, for a programmed number of times (interrupt persistence). There are two interrupt modes: the interrupt will remain latched in the normal mode until the interrupt status flag is read by the host firmware. If set to a logic mode, the interrupt will be asserted when the PS value rises above the high threshold level, and de-asserted when the PS value falls below the low threshold level. The logic mode is useful when an autonomous operation with some external circuit is required, while the normal mode is best suited to be used with the MCU. The INT pin is routed to the INT pin of the mikroBUS™.
The Click board™ is supported by the mikroSDK library, which contains functions for simplified development. The mikroSDK functions are well-documented, but there is still a need, the datasheet of the VCNL4040 offers a listing of all the registers and their specific functions.
The Click board™ is designed to work with 3.3V only. When using it with MCUs that use 5V levels for their communication, a proper level translation circuit should be used.
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