LightRanger 3 Click
PID: MIKROE-3103
Weight: 23 g
Light Ranger 3 click is an accurate distance measurement Click board™ based on a
ToF (Time of Flight) measurement principle. The Simblee™
enabled RFD77402 rangefinder module from RF Digital is a complete measurement
stack on the chip. It is surprisingly easy to work with, as this highly integrated range
finder module exposes the only I2C interface and INT pin to the host controller. It
features the VCSEL, a Vertical Cavity Surface Emitting Laser, used to emit a narrow
band of a harmless modulated light beam in the IR range (850 nm), and a receive
sensor, which can detect the reflected light. It can measure distances up to 2000mm,
with up to 10% accuracy. The device is rated Class 1 LASER product, operating in the
IR (invisible) spectrum range.
ToF based light distance meters and rangefinders are one of the most accurate
contactless distance measuring devices. The ability to precisely measure distance
without making actual contact, allows Light Ranger 3 to be used in industry - for
counting dimensions of goods in industry, controlling a safety area, building contactless
digital measurement tools. Some other uses for this device could be building 3D visual
guidance applications in robotics, for moving it through obstacles, and similar.
How does it work?
Light Ranger 3 click uses the Simblee™ enabled RFD77402 ToF sensor module
from RF Digital. This sensor uses the VCSE (Vertical Cavity Surface Emitting)
narrowband LASER, which emits light in the range of 850 nm. The light emission is in
the IR range of the spectrum and it is not visible by a human eye. It is received by the IR
sensor and processed by the integrated sections of the RFD77402, giving an 11-bit
result on the output register, available via the standard I2C interface. The device is
rated as Class 1 LASER product, and it does not cause harmful eye injuries. However, it
should not be pointed towards the eyes.
The highly integrated RFD77402 ToF sensor encompasses several integrated sections.
It has an embedded MCU, OTP memory, RAM area, ranging processing unit and the
VCSEL driver. It exposes a simple I2C interface for the communication with the host
MCU, offering a range of registers, used for configuring and status reporting. In addition,
it offers an interrupt pin (INT) routed to the INT pin of the mikroBUS™. Highly
configurable interrupt engine allows this pin to be configured to generate interrupt
signals for various events, alerting the host MCU about some important status changes,
such as the Data Ready event, for example. It can be set to work in both open-drain
configurations, as well as in the push-pull mode. The Click board™ is equipped with the
10K pull-up resistor, so it is advised to configure the INT pin in open-drain mode.
The measurement is done by comparing the modulation shift of the light in the reflected
beam. Therefore, the range and the accuracy depend on the material of the measured
object, as well as the photo - pollution of the IR spectrum. The module is designed to
suppress the noise and interference. The narrow Field of Illumination (29°) allows
focused measurement and prevents beam scattering. The receiver has a bit wider Field
of View (55°), allowing it to catch the reflected beam. The measurement is naturally
affected by the IR reflectance of an object, so best results are achieved when
measuring the distance of the objects that have high IR reflectance. The maximum
range that can be measured is 2000mm, while the minimum operational range is
100mm. The measurement error is linear, and it grows with the distance. It stays within
10% of the distance
The Click board™ uses only 3.3V power rail from the mikroBUS™. No additional
jumpers or selectors exist on the Click board™ since the RFD77402 ToF sensor module
is highly integrated and requires a minimum number of external components to work.
The RFD77402 module datasheet offers an extensive information about internal
registers and how to configure them. However, the click comes with the library of
functions that provide simplified operation and measurement. The use of these
functions is demonstrated in the example, which can be used as the reference for
custom design.
Specifications
Type
Optical
Applications
Can be used for counting dimensions of goods in industry, controlling a safety
area, building contactless digital measurement tools, 3D visual guidance
applications in robotics, for moving it through obstacles, and similar
On-board
modules
Simblee™ enabled RFD77402 ToF sensor module, from RF Digital
Key Features
Contactless measurement up to 2000m, with up to 10% accuracy. The device
is rated Class 1 laser product, operating in the IR (invisible) spectrum range.
Integrated sections allow minimum number of external components to be used
Interface
I2C
Input Voltage
3.3V
Click board
size
S (28.6 x 25.4 mm)
Pinout diagram
This table shows how the pinout on LightRanger 3 Click corresponds to the pinout on
the mikroBUS™ socket (the latter shown in the two middle columns).
Notes
Pin
Pin
Notes
NC
1
AN
PWM
16
NC
NC
2
RST
INT
15
INT
NC
3
CS
RX
14
NC
NC
4
SCK
TX
13
NC
NC
5
MISO
SCL
12
SCL
I2C Clock
NC
6
MOSI
SDA
11
SDA
I2C Data
Power supply
3.3V
7
3.3V
5V
10
NA
Ground
GND
8
GND
GND
9
GND
Interrupt OUT
Ground
Onboard settings and indicators
Label
PWR
Name
Default
PWR
-
Description
Power LED indicator
Software support
We provide a library for the LightRanger_3 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
The library initializes and defines the I2C bus driver and drivers that offer a choice for
writing data in registers and reading data from registers. The library includes functions
for full initialization chip with the procedure is written following the instructions from the
datasheet. The user has the functions available for softReset, read distance and
confidence distance value, Then functions for go to standby mode, go to off mode, go to
on mode and measurement mode.
Key functions:
uint8_t lightranger3_init() - Functions for initializes chip
uint8_t lightranger3_takeSingleMeasurement() - Functions for measurement
uint16_t lightranger3_getDistance() - Functions for reads distance
Example description
The application is composed of three sections:
System Initialization - Initializes I2C module and sets the INT pin as INPUT
Application Initialization - Initializes driver init and configuration chip
Application Task - (code snippet) - Includes measurements, reads distance, and logs distance
to USBUART for every 300 ms. Distance measurement at distances ranging from 100 mm to
2000 mm
void applicationTask()
{
lightranger3_takeSingleMeasurement();
Distance = lightranger3_getDistance();
IntToStr(Distance,DistanceTxt);
mikrobus_logWrite( "Distance =", _LOG_TEXT );
mikrobus_logWrite( DistanceTxt, _LOG_TEXT );
mikrobus_logWrite( " mm", _LOG_LINE );
Delay_ms( 300 );
}
The full application code, and ready to use projects can be found on our LightRanger 3
click LibStock page.
Other mikroE Libraries used in the example:
Configuration
I2C
UART
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/lightranger‐3‐click 9‐19‐18