Microwave 2 click (for EU)
PID: MIKROE-3187
Weight: 27 g
Microwave 2 click is an accurate and reliable short to medium range motion detection
Click board™, based on a Doppler radar principle. Thanks to the highly
integrated NJR4265RF2C1, an intelligent 24GHz microwave motion sensor, it can
accurately sense the movement of a low-speed object. Featuring an integrated RF
circuit, IF amplifier, and the MCU with its accompanying circuitry, it is able to provide
signal processing, allowing better isolation of the useful movement signal and reduction
of the background noise. In addition, it can detect an object approaching or leaving
away, and autonomously signalize the detected event.
Note: Microwave 2 click board is available for all of EU regions.
Microwave 2 click uses a UART interface, simplifying the firmware development. A
benefit of having an integrated MCU on the module is that the ability to autonomously
work, even without the MCU. The detected approach or leave event can be signalized
either on two differently colored LEDs or via the PINs, routed to the mikroBUS™.
However, to use some advanced features, set detection and threshold parameters,
operating modes, and other configuration options, the MCU is necessary. Microwave 2
click is an ideal solution for building safety and security applications, entrance and exit
management applications, and other applications that rely on a reliable moving object
detection.
How does it work?
The Microwave 2 click can detect movement by utilizing the NJR4265RF2C1, an
intelligent 24GHz microwave motion sensor, from JRC. The onboard microwave motion
sensor is based on the Doppler effect. It transmits waves and picks them back as they
get reflected from a moving object. According to Doppler effect principle, the
movement of an object relative to the position of the listener (sensor in this case),
causes the reflected waves to increase their frequency when the object approaches, or
decrease their frequency as the object moves away (leaves). Comparing the reflected
waves with the base frequency at which the waves are transmitted can reveal the object
movement properties.
The integrated MCU of the NJR4265RF2C1 module processes the signal reduces the
noise and enhances the useful signal, allowing reliable detection and steady sensing of
the movement. It then makes a movement direction decision, based on the collected
data and signals it back to the host MCU.
Two LEDs, labeled as DL (green) and DA (yellow) are routed to the dedicated module
pins, labeled as DETECT APPROACHING and DETECT LEAVING. These pins will
signal the corresponding events when they are detected by the sensor. The pins are
also routed to the mikroBUS™ AN and INT pins respectively labeled as DA and DL on
the Click board™. This way, the movement detection events can be signaled to the host
MCU, too.
The NJR4265RF2C1 module is able to sense moving objects up to 10m in front of the
sensor. The detection cone is about ±35° in respect to the central perpendicular axis of
the sensor. The object motion speed should be in the range between 0.25 m/s to 1 m/s.
The frequency stability of the emitted waves is in the range of 1MHz below, and up to
the center frequency of 24.15 to 24.25 GHz, over the temperature range from -20 °C to
+60 °C, allowing steady and accurate detection in various conditions. Wave reflections
caused by random objects like leaves, air movement, insects, and other similar objects,
is suppressed by the on-chip integrated MCU, increasing the target object detection
reliability. However, due to its nature, the noise suppression algorithm limits the
detectable object speed and size, which sometimes can be undesirable. Having in mind
these limitations, the module is best used in applications where larger, slow-moving
objects detection is required, such as the pedestrian movement applications, human or
animal detection applications, and similar.
The host MCU can communicate with the Microwave 2 click using the UART interface.
The NJR4265RF2C1 module has its UART pins routed to the RX and TX pins of the
mikroBUS™. The UART communication parameters are fixed to 9600 bps, 8 data bits,
no parity, and one stop bit (9600, 8, N, 1). The MCU can use the UART commands to
set the detection thresholds, set the sensor mode, perform acquisition of the detection
results and other sensor data. The NJR4265RF2C1 module datasheet offers a list of
UART commands, with the detailed explanation of each. However, Microwave 2 click is
supplied with the library compatible with all the MikroE compilers, offering a set of
functions for simplified control and rapid development of custom applications.
Microwave 2 click can be interfaced with both 3.3V and 5V MCUs. To select the
appropriate operating voltage of the module, the SMD jumper labeled as the PWR SEL
can be moved to the desired voltage position, clearly labeled underneath the jumper
itself.
Specifications
Type
Motion
Applications
Microwave 2 click is an ideal solution for building safety and security
applications, entrance and exit management applications, and other
applications that rely on a reliable moving object detection
On-board
modules
NJR4265RF2C1, an intelligent 24GHz microwave motion sensor, from
JRC
Key Features
Motion detection based on Doppler shift of microwave frequency, an
integrated MCU used to provide on-chip signal processing, including noise
reduction, useful signal enhancement, low power consumption, simplified
UART interface, detection of both object approaching and moving away,
indicated by two LEDs and dedicated pins
Interface
GPIO,UART
Input Voltage
3.3V or 5V
Compatibility
mikroBUS
Click board size
M (42.9 x 25.4 mm)
Pinout diagram
This table shows how the pinout on Microwave 2 Click corresponds to the pinout on
the mikroBUS™ socket (the latter shown in the two middle columns).
Notes
Pin
Pin
Notes
Object Approaching
DA
1
AN
PWM
16
NC
NC
2
RST
INT
15
DL
Object Leaving
NC
3
CS
RX
14
TX
UART TX
NC
4
SCK
TX
13
RX
UART RX
NC
5
MISO
SCL
12
NC
NC
6
MOSI
SDA
11
NC
Power supply
3.3V
7
3.3V
5V
10
5V
Ground
GND
8
GND
GND
9
GND
Power supply
Ground
Onboard jumpers and settings
SCH
Label
PCB
Name
Default
Position
Description
LD1
DL
-
Object moving away LED indicator (green)
LD2
DA
-
Object approaching LED indicator (red)
LD3
PWR
-
Power LED indicator
PWR
SEL
PWR SEL
Left
Power Supply voltage selection: left position 3.3V,
right position 5V
Software support
We provide a library for the Microwave 2 Click on our LibStock page, as well as a demo
application (example), developed using MikroElektronika compilers. The demo can run
on all the main MikroElektronika development boards.
Library Description
This library provides generic functions for communication with the click board.
Key functions:
uint8_t microwave2_readByte(); - Function for reading a byte of data from the serial port.
uint8_t microwave2_byteReady(); - Function for testing if a byte has been received from the click
void microwave2_uartHandler(uint8_t *packegBuffer, uint8_t rData); - Handler function for byte's
uint8_t microwave2_checkTrafic(); - Function will give different return values depending on the data
board.
received from the click board.
handled in the handler function.
Example description
The application is composed of three sections :
System Initialization - Initializes GPIO and UART structures.
Application Initialization - Initializes the click board for communication.
Application Task - Data sen't from the click board is captured and different actions are applied.
void applicationTask()
{
char tmp;
char rDat;
if( microwave2_byteReady() )
{
rDat=microwave2_readByte();
microwave2_uartHandler(&buf,rDat);
}
tmp = microwave2_checkTrafic();
if(tmp == MICROWAVE2_MOVING_CLOSER)
{
mikrobus_logWrite("Approaching",_LOG_LINE);
}
if(tmp == MICROWAVE2_STOPPED_MOVING)
{
mikrobus_logWrite("No movesment",_LOG_LINE);
}
if(tmp == MICROWAVE2_MOVING_AWAY)
{
mikrobus_logWrite("Moving away",_LOG_LINE);
}
}
The full application code, and ready to use projects can be found on
our LibStock page.
Other mikroE Libraries used in the example:
UART Library
Additional notes and information
Depending on the development board you are using, you may need USB UART
click, USB UART 2 click or RS232 click to connect to your PC, for development
systems with no UART to USB interface available on the board. The terminal
available in all MikroElektronika compilers, or any other terminal application
of your choice, can be used to read the message.
mikroSDK
This click board is supported with mikroSDK - MikroElektronika Software Development
Kit. To ensure proper operation of mikroSDK compliant click board demo applications,
mikroSDK should be downloaded from the LibStock and installed for the compiler you
are using.
For more information about mikroSDK, visit the official page.
https://www.mikroe.com/microwave‐2‐eu‐click 10‐11‐18