RFLINK-UART Wireless UART Transmission Module Instruction Manual
- June 5, 2024
- Rflink
Table of Contents
RFLINK-UART Wireless UART Transmission Module Instruction Manual
The RFLINK-UART Wireless UART Transmission Module is an easy-to-use module that instantly and painlessly upgrades wired UART to wireless UART 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
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
**Root
| Device
---|---
GND** à Ground
+5V à 5V voltage input
The TX à corresponds to the RX of the development board UART
The RX à corresponds to the TX of the development board UART
THE CEB à 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 à Output pin of IO Port (On/Off export)
IN àInput pin of the IO Port (On/Off receive).
ID1, ID0 àselects which device to connect to via the HIGH/LOW combination of these two pins.
ID_Lat à 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 à Ground
+5V à 5V voltage input
The TX à corresponds to the RX of the development board UART
The RX à corresponds to the TX of the development board UART
THE CEB à 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 à Output pin of IO Port (On/Off export)I
IN à Input pin of the IO Port (On/Off receive).
ID1, ID0 à Through the HIGH/LOW combination of these two pins, the Device can be set to different device numbers.
ID_Lat à 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
| Device 1 (#1)| Device 2 (#2)| Device 3 (#3)|
Device 4 (#4)
---|---|---|---|---
ID0 pin| HIGH| HIGH| LOW| LOW
ID1 pin| HIGH| LOW| HIGH| LOW
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
first,
the root will choose the target device via the same table.
You can choose the different device to transfer message via the ID0 and ID1 of root, usually tie 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.
| Arduino (Italy) | D2 | D3 | D5 | D7 | D8 | 5V | GND |
|---|---|---|---|---|---|---|---|
| RFLINK- UART | RX | TX | ID_Lat (Root) | ID0 |
(Root)
| ID1
(Root)
| 5V| GND CEB
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 RFLINKUART 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.
