ARDUINO RFLINK-UART Wireless UART Transmission Module Instruction Manual
- October 30, 2023
- ARDUINO
Table of Contents
ARDUINO RFLINK-UART Wireless UART Transmission Module
Product Information
The RFLINK-UART Wireless UART Transmission Module is a module that upgrades wired UART to wireless UART transmission without any coding effort or hardware. The module contains one root terminal and up to four device ends with a set of I/O ports. The operating voltage ranges from 3.3V to 5.5V, and the RF frequency ranges from 2400MHz to 2480MHz. The transmission distance is around 80 to 100m in the open space, and the transmission rate is 250Kbps. The module supports 1-to-1 or 1-to-multiple (up to four) transmission.
PRODUCT Module Characteristics
- Operating voltage: 3.3~5.5V
- RF Frequency: 2400MHz~2480MHz
- Power consumption: 24 mA@ +5dBm at TX mode and 23 mA at RX mode.
- Transmit power: +5dBm
- Transmission rate: 250Kbps
- Transmission distance: around 80 to 100m in the open space
- Baud rate9,600bps or19,200bps
- Supports 1-to-1 or 1-to-multiple (up to four)transmission.
Module Appearance and Dimension
The RFLINK-UART module contains one root terminal and up to four device
ends. The root terminal and the device end are outward-looking the same, and
they can be identified by the label on the back. The group ID of the RFLINK-
UART module is 0001, and the BAUD is 9600.
PRODUCT Pin Definition
| Root | Device |
|---|---|
| ID0 | ID0 |
| ID1 | ID1 |
| IO | IO |
| 5V | 5V |
| GND | GND |
Product Usage Instructions
Setup Root and Devices
All types of development boards and MCUs that support the UART
communication interface can use this module directly, and there is no need to
install additional drivers or API programs. The RFLINK-UART wireless UART
transmission module supports 1-to-multiple type, default Root terminal (#0)
after power-on with a device (#1) is connected if you have another numbered
Device (#2~#4). You can select different device sides you want to connect to
via the ID0 and ID1 pins on the root side.
For the ID0/ID1 combination of device selection, refer to the table below:
| Device 1 (#1) | Device 2 (#2) | Device 3 (#3) | Device 4 (#4) |
|---|
ID0 pin: HIGH
ID1 pin: HIGH| ID0 pin: HIGH
ID1 pin: LOW| ID0 pin: LOW
ID1 pin: HIGH| ID0 pin: LOW
ID1 pin: LOW
The device side should be set to the required device number according to first, the root will choose the target device via the same table. You can choose a different device to transfer the message via the ID0 and ID1 of the root, usually tie ID0 or/and ID1 to the GND. More than that, the root side can also send a Low/High signal through the IO pin to choose the target device on the fly For example, in the figure below, Arduino Nano selects the Device to connect via the D4 and D5 pins. After sending the corresponding High/Low signal to the ID0 and ID1 pins, the Root terminal will interrupt the transmission with the old connection end (that is, stop the transmission and receiving with the old connection end). And wait for a Low signal from the ID_Lat pin to switch to the new connection..
The RFLINK-UART Wireless UART Transmission Module is an easy-to-use module that instantly and painlessly upgrades wired UAR to wireless UAR transmission. More than that , there is a set of I/O port there , thus you don’t need any coding effort and hardware to make IO switches well controlled remotely.
Module Appearance and Dimension
The RFLINK-UART module contains one root terminal (left) and up to four Device
end (on the right side of the figure below, might be numbered from 1 to 4),
the two are outward-looking the same, it can be identified by the label on the
back . As shown below, the Group ID of the RFLINK-UART module is 0001 and the
BAUD is 9600. 
Module characteristics
- Operating voltage: 3.3~5.5V
- RF Frequency: 2400MHz~2480MHz。
- Power consumption: 24 mA@ +5dBm at TX mode and 23mA at RX mode.
- Transmit power: +5dBm
- Transmission rate: 250Kbps
- Transmission distance: around 80 to 100m in the open space
- Baud rate： 9,600bps or19,200bps
- Supports 1-to-1 or 1-to-multiple (up to four) transmission.
Pin definition
- GND→ Ground
- +5V→ 5V voltage input
- The TX → corresponds to the RX of the development board UART
- The RX → corresponds to the TX of the development board UART
- THE CEB → This CEB should connect to the ground (GND),then the module will be power-on and can be used as a power-saving control function.
- OUT→ Output pin of IO Port (On/Off export)
- IN→Input pin of the IO Port (On/Off receive).
- ID1, ID0 →selects which device to connect to via the HIGH/LOW combination of these two pins.
- ID_Lat→ Device ID Latch pins. When Root sets the target device via ID0, ID1, you need to set this pin LOW then the connection will officially be switched to the specified device.
- GND→ Ground
- +5V→ 5V voltage input
- The TX→ corresponds to the RX of the development board UART
- The RX→ corresponds to the TX of the development board UART
- THE CEB→ This CEB should connect to the ground (GND),then the module will be power-on and can be used as a power-saving control function.
- OUT→ Output pin of IO Port (On/Off export)I
- IN→ Input pin of the IO Port (On/Off receive).
- ID1, ID0 → Through the HIGH/LOW combination of these two pins, the Device can be set to different device numbers. ID_Lat→ This Pin foot has no effect on Device.
How to use
All types of development boards and MCUs that support the UART communication interface can use this module directly, and there is no need to install additional drivers or API programs.
Setup Root and Devices
The traditional wired TTL is 1 to 1 transmission, the RFLINK-UART wireless
UART transmission module will support 1-to-multiple type, default Root
terminal (#0) after power-on with device (#1) is connected if you have another
numbered Device (#2~# 4). You can select different device side you want to
connect to via the ID0 and ID1 pins on the root side. For the ID0/ID1
combination of device selection, please refer to the table below.
ID0, ID1 pin are default HIGH, they will be LOW via connecting to the ground.
Note: Device side should be set to the required device number according to first, the root will choose the target device via the same table.
You can choose a different device to transfer messages via the ID0 and ID1 of
the root, usually tying ID0 or/and ID1 to the GND. More than that, the root
side can also send Low/High signal through the IO pin to choose the target
device on the fly. For example, in the figure below, Arduino Nano selects the
Device to connect via the D4 and D5 pins 。
After sending the corresponding High/Low signal to the ID0 and ID1 pins, the Root terminal will interrupt the transmission with the old connection end (that is, stop the transmission and receiving with the old connection end). And wait for a Low signal from the ID_Lat pin to switch to the new connection.
Start transmitting/receiving messages with the new connection
After you send the target device number signal via ID0, ID1, all transection
between the root and the current connected device will be halted. The new
transection won’t start until you send a LOW signal of ID_Lat at least 3ms.
There are three use cases for Arduino, Raspberry Pi, and sensors.
Working with Arduino
In addition to using Arduino’s hardware TX/RX ports directly, this module also
supports software serials, so it can Use in a software-emulated UART to avoid
occupying the physical UART interface. The following example is connecting D2
and D3 to TX and the Root side of the RFLINK-UART module through the software
serial RX, D7, D8 are the pins that set the connection to the device, and D5
is used as the ok toggle pin. Through Arduino’s instructions, digitalWrite
outputs LOW or HIGH for the D7, D8 and D5 pins We can achieve the ability to
dynamically connect to different devices.
Example of a root-side transport program:
Example of RX receiver-side program 
execute
Working with the Raspberry Pi
Using this mod on the Raspberry Pi is also fairly easy! The pins of the
RFLINK-UART module are connected to the corresponding ones of the Raspberry Pi
as in the example of the Arduino above. In other words, you can read and write
directly to the RX/TX pin and specify the device to connect, just like a
traditional UART. The following figure shows the connection method between the
Root-side Raspberry Pi and the RFLINK-UART module, and the connection method
of the Device end is basically the same, but it ID_ The Lat pin pin does not
need to be connected, and ID0 and ID1 are set to different ID numbers
depending on the requirements.
Example of program:
The transmitter repeatedly transmits information to device #3 and device #1
Receiver: This example is a simple receive
Direct connecting with sensor
If your sensor supports the UART interface and the Baud rate supports 9,600 or
19,200 , then you can directly connect it to the device side of the RFLINK-
UART module, and you can quickly and painlessly upgrade it Wireless function
sensor too. The following G3 PM2.5 sensor is taken as an example, refer to the
following connection method
Next, please prepare a development board (either Arduino or Raspberry Pi) to connect the RO of the RFLINK-UART module On the ot side, you can read the G3 transmission in the general UART way PM2.5 data, congratulations, the G3 has been upgraded to a PM2.5 sensing module with wireless transmission capabilities.
Use IO Ports
The RFLINK-UART module provides a set of IO ports that allow you to transmit
on/off commands wirelessly, and this set Io Ports are not limited to the
transmission or receiving end of the module, and both ends can control each
other. As long as you change the voltage of the IN port at either end, you
will change the output voltage of the Out port at the other end synchronously.
Please refer to the following usage example to explain how to use IO Port to
remotely control the switch LED bulb.
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