Create ambiance like never before and transform spaces with ease using BH1721FVC and PIC32MZ1024EFH064

Ambient 4 Click is based on the BH1721FVC, a 16-bit digital light sensor with the I2C serial interface from Rohm Semiconductor. This sensor has many features that make it a perfect solution for small designs such as the Ambient 4 Click board™. One of these features is certainly its high level of integration, that allows a minimal number of external components, leaving room for an additional I2C level translator IC, labeled as PCA9306, a reliable I2C level translator from Texas Instruments, proven in many designs. This allows a high number of microcontrollers (MCUs) to be interfaced with Ambient 4 click. The BH1721FVC sensor is also immune to flickering and its accuracy is not influenced by the light source type. It is calibrated so its spectral response is closely matched to a spectral response of the human eye. The BH1721FVC sensor of Ambient 4 click can operate in two modes: it can be operated in Low-Resolution mode and High-Resolution mode. While operating in the Low-Resolution mode, the measuring resolution is 8 lx per step. When operated in a High-Resolution mode, the accuracy is 1 lx per step. When sensing very low amounts of light, it is mandatory to use High-Resolution mode, since it is not possible to obtain valid results in Low-Resolution mode. The resolution can

be also fine-tuned by changing the measurement time. This is used to increase the sensitivity of the sensor, as well as to reduce the influence of the optical window if one is mounted over the sensor. Increasing of the measurement time allows light amount down to 0.25 lx to be detected. The Low-Resolution mode, in general, allows much shorter measurement times, while high resolution will use longer to place the conversion data on the 16-bit output register. As mentioned already, the spectral response of the sensor is closely matched to the response of the human eye. This means that the sensor outputs highest results for the light spectrum range between 500nm and 650 nm, which includes most of the light energy in the visible light spectrum: this is a color range from cyan to orange. The datasheet of the BH1721FVC offers a more accurate representation of the spectrum response, as well as for other operating parameters. The sensitivity of the sensor is also affected by the incidence angle of the light rays. The BH1721FVC datasheet offers an accurate representation of the sensor's field of view (FOV), but a light source with the incidence angle of ±45˚ will result with the measured ratio of 0.8 times compared to the same light source intensity perpendicular to the surface of the sensor. Since

the sensor output result is 16-bit, it is stored in the LSB/MSB format, in two separate output registers. To obtain a measurement data in proper units (Lux, lx), a data conversion has to be performed by the firmware of the host MCU. The datasheet of the BH1721FVC contains these conversion formulas, although Ambient 4 click comes supported by a library that contains the functions that simplify the use of the Click board™. The 16-bit light intensity data is present at the I2C interface output. The I2C bus lines are routed to the aforementioned PCA9306 level translator. This allows interfacing with the wide range of different MCUs, both 3.3V, and 5V. It is worth mentioning that the sensor requires a reset after the power-up sequence, in order to set its internal registers to their defaults. This can be achieved by pulling the DVI line of the sensor to a LOW logic level for at least 1 µs. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used as a reference for further development.

PIC32MZ Clicker is a compact starter development board that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It comes with an onboard 32-bit PIC32MZ microcontroller with FPU from Microchip, a USB connector, LED indicators, buttons, a mikroProg connector, and a header for interfacing with external electronics. Thanks to its compact design with clear and easy-recognizable silkscreen markings, it provides a fluid and immersive working experience, allowing access anywhere and under

any circumstances. Each part of the PIC32MZ Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the PIC32MZ Clicker programming method, using USB HID mikroBootloader, or through an external mikroProg connector for PIC, dsPIC, or PIC32 programmer, the Clicker board also includes a clean and regulated power supply module for the development kit. The USB Micro-B connection can provide up to 500mA of current, which is more than enough to operate all onboard

and additional modules. All communication methods that mikroBUS™ itself supports are on this board, including the well-established mikroBUS™ socket, reset button, and several buttons and LED indicators. PIC32MZ Clicker is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.