Our innovative solution combines two 275nm UV-C LEDs with a green LED to provide a visual indicator, helping users identify and avoid direct exposure to potentially harmful UV-C light
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Hardware Overview
How does it work?
UVC Light Click uses two 0.7W, 275nm LEDs and one green LED that allow users to see the approximate area where UVC light is shining since these UV wavelengths are not visible to the human eye and should avoid direct exposure to the eye. UVC Light Click can be used as a disinfection tool because DNA, RNA, and proteins absorb UV light in the range of 200 nm to 300 nm. Absorption by proteins can lead to the rupture of cell walls and the organism's death. Absorption by DNA or RNA (specifically by thymine bases) is
known to cause inactivation of the DNA or RNA double helix strands by forming thymine dimers. If enough of these dimers are created in DNA, the DNA replication process is disrupted, and the cell cannot replicate. It is widely accepted that it is not necessary to kill pathogens with UV light but rather apply enough UV light to prevent the organism from replicating. The UV doses required to prevent replication are orders of magnitude lower than required to kill, making the cost of UV treatment to prevent infection commercially
viable. UVC Light Click is implementing a TPS61169 LED driver with PWM brightness control to drive LEDs in series and an MC34671 battery charger to allow charging of battery when Click board™ is inserted in the mikroBUS™ socket; CHG LED will indicate the charging in progress and will turn off once the battery charging is finished. When the PWR SEL jumper is repositioned to the right position, you can use UVC Light and click standalone if no dimming is necessary or high mobility is needed.
Features overview
Development board
Nucleo-64 with STM32F446RE MCU offers a cost-effective and adaptable platform for developers to explore new ideas and prototype their designs. This board harnesses the versatility of the STM32 microcontroller, enabling users to select the optimal balance of performance and power consumption for their projects. It accommodates the STM32 microcontroller in the LQFP64 package and includes essential components such as a user LED, which doubles as an ARDUINO® signal, alongside user and reset push-buttons, and a 32.768kHz crystal oscillator for precise timing operations. Designed with expansion and flexibility in mind, the Nucleo-64 board features an ARDUINO® Uno V3 expansion connector and ST morpho extension pin
headers, granting complete access to the STM32's I/Os for comprehensive project integration. Power supply options are adaptable, supporting ST-LINK USB VBUS or external power sources, ensuring adaptability in various development environments. The board also has an on-board ST-LINK debugger/programmer with USB re-enumeration capability, simplifying the programming and debugging process. Moreover, the board is designed to simplify advanced development with its external SMPS for efficient Vcore logic supply, support for USB Device full speed or USB SNK/UFP full speed, and built-in cryptographic features, enhancing both the power efficiency and security of projects. Additional connectivity is
provided through dedicated connectors for external SMPS experimentation, a USB connector for the ST-LINK, and a MIPI® debug connector, expanding the possibilities for hardware interfacing and experimentation. Developers will find extensive support through comprehensive free software libraries and examples, courtesy of the STM32Cube MCU Package. This, combined with compatibility with a wide array of Integrated Development Environments (IDEs), including IAR Embedded Workbench®, MDK-ARM, and STM32CubeIDE, ensures a smooth and efficient development experience, allowing users to fully leverage the capabilities of the Nucleo-64 board in their projects.
Microcontroller Overview
MCU Card / MCU

Architecture
ARM Cortex-M4
MCU Memory (KB)
512
Silicon Vendor
STMicroelectronics
Pin count
64
RAM (Bytes)
131072
You complete me!
Accessories
Click Shield for Nucleo-64 comes equipped with two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the STM32 Nucleo-64 board with no effort. This way, Mikroe allows its users to add any functionality from our ever-growing range of Click boards™, such as WiFi, GSM, GPS, Bluetooth, ZigBee, environmental sensors, LEDs, speech recognition, motor control, movement sensors, and many more. More than 1537 Click boards™, which can be stacked and integrated, are at your disposal. The STM32 Nucleo-64 boards are based on the microcontrollers in 64-pin packages, a 32-bit MCU with an ARM Cortex M4 processor operating at 84MHz, 512Kb Flash, and 96KB SRAM, divided into two regions where the top section represents the ST-Link/V2 debugger and programmer while the bottom section of the board is an actual development board. These boards are controlled and powered conveniently through a USB connection to program and efficiently debug the Nucleo-64 board out of the box, with an additional USB cable connected to the USB mini port on the board. Most of the STM32 microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the STM32 Nucleo-64 board with our Click Shield for Nucleo-64, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic

Step by step
Project assembly
Track your results in real time
Application Output
1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.

2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.

3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.

Software Support
Library Description
This library contains API for UVC Light Click driver.
Key functions:
uvclight_pwm_start
- This function starts PWM moduleuvclight_set_duty_cycle
- This function sets the PWM duty cycleuvclight_pwm_stop
- This function stops PWM module.
Open Source
Code example
The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.
/*!
* @file
* @brief UvcLight Click example
*
* # Description
* This click has ultraviolet LEDs with 275nm wavelength. UVC radiation refers to wavelengths
* shorter than 280 nm. Because of the spectral sensitivity of DNA, only the UVC region
* demonstrates significant germicidal properties.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver.
*
* ## Application Task
* Increases and decreases the pwm duty cycle.
* Results are being sent to the Usart Terminal where you can track their changes.
*
* CAUTION! High intensity UV Light - avoid eye and skin exposure. Avoid looking direclty at light!
*
* @author Nikola Peric
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "uvclight.h"
// ------------------------------------------------------------------ VARIABLES
static uvclight_t uvclight;
static log_t logger;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
uvclight_cfg_t cfg;
/**
* Logger initialization.
* Default baud rate: 115200
* Default log level: LOG_LEVEL_DEBUG
* @note If USB_UART_RX and USB_UART_TX
* are defined as HAL_PIN_NC, you will
* need to define them manually for log to work.
* See @b LOG_MAP_USB_UART macro definition for detailed explanation.
*/
LOG_MAP_USB_UART( log_cfg );
log_init( &logger, &log_cfg );
log_info( &logger, "---- Application Init ----" );
// Click initialization.
uvclight_cfg_setup( &cfg );
UVCLIGHT_MAP_MIKROBUS( cfg, MIKROBUS_1 );
uvclight_init( &uvclight, &cfg );
uvclight_set_duty_cycle ( &uvclight, 0.0 );
uvclight_pwm_start( &uvclight );
Delay_ms( 100 );
log_info( &logger, "---- Application Task ----" );
}
void application_task ( void )
{
static int8_t duty_cnt = 1;
static int8_t duty_inc = 1;
float duty = duty_cnt / 10.0;
uvclight_set_duty_cycle ( &uvclight, duty );
log_printf( &logger, "Duty: %d%%\r\n", ( uint16_t )( duty_cnt * 10 ) );
Delay_ms( 500 );
if ( 10 == duty_cnt )
{
duty_inc = -1;
}
else if ( 0 == duty_cnt )
{
log_printf( &logger, "Cooldown 2 SEC\r\n");
Delay_ms( 2000 );
duty_inc = 1;
}
duty_cnt += duty_inc;
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END