Create responsive, energy-efficient systems that adapt to user presence and needs with PD-V11 and STM32F091RC

From Sci-Fi to reality

Microwave Click with Nucleo-64 with STM32F091RC MCU

Published Feb 26, 2024

Click board™

Microwave Click

Dev Board

Nucleo-64 with STM32F091RC MCU

Compiler

NECTO Studio

MCU

STM32F091RC

This solution, which employs the Doppler effect with microwaves, provides the ability to detect and track motion with precision, opening doors to a wide range of applications

Hardware Overview

How does it work?

Microwave Click is based on the PD-V11, a 24GHz microwave motion sensor from Pdlux. The typical use for Microwave click is a proximity or motion detector in various applications and devices. The Microwave click can detect movement or proximity by using the Doppler effect. The onboard microwave motions sensor transmits waves, and picks them back as they hit an object, with their frequency changed. Microwave click does not need optical visibility to work, and the waves can penetrate many kinds of barriers and obstacles. Microwave click detects movement of objects utilizing Doppler effect. When the PD-V11 microwave sensor is powered on, it starts transmitting radio waves of fixed frequency. As the waves hit a moving object they are reflected back toward PD-V11 microwave motion sensor, with their frequency changed, depending on speed

and direction of object's movement. The Doppler effect - a change in frequency of a wave for the observer and object move closer or further apart from one another. A typical example of the Doppler effect is when a vehicle with siren passes and you hear the pitch drop of the siren. The PD-V11 microwave motion sensor low power consumption, low noise, and a low wireless power output. See the datasheet to learn more. The PD-V11 microwave motion sensor picks up reflected waves and converts them to a voltage signal. This signal has the magnitude of several hundred microvolts, so it's sent to the MCP6022 which amplifies the signal, in order to make it readable over the Analog pin on the mikroBUS™. This signal is amplified up to 3.3V. Once amplified, the signal is routed to the Analog pin (OUT) on the mikroBUS™ line. The proximity of the object can

be determined by measuring the amplitude of this signal, and speed/direction by determining its frequency. The PD-V11 microwave motion sensor low power consumption, low noise, and a low wireless power output. See the datasheet to learn more. The PD-V11 microwave motion sensor picks up reflected waves and converts them to a voltage signal. This signal has the magnitude of several hundred microvolts, so it's sent to the MCP6022 which amplifies the signal, in order to make it readable over the Analog pin on the mikroBUS™. This signal is amplified up to 3.3V. Once amplified, the signal is routed to the Analog pin (OUT) on the mikroBUS™ line. The proximity of the object can be determined by measuring the amplitude of this signal, and speed/direction by determining its frequency.

Features overview

Development board

Nucleo-64 with STM32F091RC 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.

Nucleo 64 with STM32F091RC MCU double side image

Microcontroller Overview

MCU Card / MCU

Architecture

ARM Cortex-M0

MCU Memory (KB)

256

Silicon Vendor

STMicroelectronics

Pin count

RAM (Bytes)

32768

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

Analog Output

PC0

RST

SCK

MISO

MOSI

3.3V

Ground

GND

PWM

INT

SCL

SDA

Power Supply

Ground

GND

Take a closer look

Schematic

Step by step

Project assembly

Click Shield for Nucleo-64 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Nucleo-64 with STM32F091RC MCU as your development board.

Nucleo 64 with STM32F401RE MCU front image hardware assembly

EEPROM 13 Click front image hardware assembly

Nucleo-64 with STM32XXX MCU MB 1 Mini B Conn - upright/background hardware assembly

Clicker 4 for STM32F4 HA MCU Step hardware assembly

Necto No Display image step 8 hardware assembly

Debug Image Necto Step hardware assembly

Track your results in real time

Application Output via Debug Mode

1. Once the code example is loaded, pressing the "DEBUG" button initiates the build process, programs it on the created setup, and enters Debug mode.

2. After the programming is completed, a header with buttons for various actions within the IDE becomes visible. Clicking the green "PLAY" button starts reading the results achieved with the Click board™. The achieved results are displayed in the Application Output tab.

Software Support

Library Description

This library contains API for Microwave Click driver.

Key functions:

microwave_generic_read - Generic ADC Read function

Open Source

Code example

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

/*!
 * \file main.c
 * \brief Microwave Click example
 *
 * # Description
 * This is an example which demonstrates the use of Microwave Click board.
 * Microwave click reads ADC results, takes exact amount of samples,
 * calculation of difference between taken samples and reference ADC value, and
 * reports movement if difference is greater/lower than selected threshold value.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the ADC and uart console where the results will be displayed.
 * Also calculates the reference ADC value for Microwave Click board.
 *
 * ## Application Task
 * Reads the AD converted results and compares this results with the previously
 * calculated reference value, taking into account the choosen threshold value
 * which controls the sensor sensitivity. All data is being displayed on the
 * USB UART where you can track their changes.
 * 
 *
 * \author Nemanja Medakovic
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "microwave.h"

// ------------------------------------------------------------------ VARIABLES

static microwave_t microwave;
static log_t logger;

static uint16_t reference;
static uint32_t sum;
static uint16_t old_detector = 0;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init( void )
{
    microwave_cfg_t cfg;
    log_cfg_t log_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.
    microwave_cfg_setup( &cfg );
    MICROWAVE_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    microwave_init( &microwave, &cfg );
    Delay_ms( 100 );

    log_printf( &logger, " Calibrating the sensor...\r\n" );
    log_printf( &logger, " There must be no movement near the sensor!\r\n" );
    log_printf( &logger, "*********************************************\r\n" );

    Delay_ms( 3000 );
    sum = 0;

    for ( uint8_t cnt = 0; cnt < MICROWAVE_SAMPLES_COUNT_100; cnt++ )
    {
        sum += microwave_generic_read( &microwave );
    }

    reference = sum / MICROWAVE_SAMPLES_COUNT_100;

    log_printf( &logger, " The sensor has been calibrated!\r\n" );
    log_printf( &logger, "** Reference value: %d\r\n", reference );
    log_printf( &logger, "*********************************************\r\n" );
    Delay_ms( 1000 );
}

void application_task( void )
{
    microwave_data_t adc_sample;
    uint16_t detector;
    uint8_t sampler;
    uint8_t cnt = 0;

    sum = 0;

    for ( sampler = 0; sampler < MICROWAVE_SAMPLES_COUNT_100; sampler++ )
    {
        adc_sample = microwave_generic_read( &microwave );
        sum += adc_sample;
        cnt++;
    }

    if ( cnt )
    {
        detector = sum / cnt;

        if ( ( ( detector + MICROWAVE_THRESHOLD_10 ) < reference || 
               ( detector - MICROWAVE_THRESHOLD_10 ) > reference ) && 
                 old_detector != detector )
        {
            log_printf( &logger, "** MOVE DETECTED!\r\n" );
            log_printf( &logger, "** Detector value : %d\r\n", detector );
            log_printf( &logger, "**************************\r\n" );
            old_detector = detector;
            Delay_ms( 100 );
        }
    }
}

void main( void )
{
    application_init( );

    for ( ; ; )
    {
        application_task( );
    }
}


// ------------------------------------------------------------------------ END