This tutorial is to highlight the differences between Address and Channel in RFBee module for wireless communication. There are two types of RFBee available in Cytron, they are RFBee 434MHz UART Wireless Module (100m) and RFBee 433MHz UART Wireless Module (1km):
RFBee 434MHz UART Wireless Module (100m)：RF operating at frequency of 434 MHz and wireless range of 100 m. This wireless range is measured under open space and may reduce if used indoors.
RFBee 433MHz UART Wireless Module (1km): Having operating frequency of 433 MHz and wireless range of 1 km. Again, this specification is measured under open space and may reduce if used indoors.
Since they have different operating frequencies, both these modules are not compatible with each other. Only modules of the same frequency can be set up to communicate wirelessly. Also, they are not compatible with low cost RF transmitters and receivers.
Both RFBee modules have similarities as follows:
- They are transceiver modules, which means they are able to receive and transmit data wirelessly.
- Both of them are use UART TTL interface protocol and half duplex (default), and able to support baud rate from 1200 bps to 115200 bps (default is 9600 bps).
- There are up to 100 channels to be configured for security and interference avoidance purpose.
- The configuration can be done with AT command.
- The supply voltage is 3.3 V.
Some other similarities :
RFBee (100m) wireless communication.
RFBee (1Km) wireless communication.
In this tutorial, I’ll show what are the differences between RFBee modules (434MHz vs 433MHz)
What is address and frequency channel of module ?
Address of module is like the module’s name. The communication frequency channels means communicating data from RFBee to another RFBee is particular frequency spectrum. If the RFBee is in different frequency, they cannot communicate.
What are the differences between RFBee (1km) module and RFBee (100m) module?
First, we must look at the configuration. RFBee (434MHz, 100m) module have address and channel configuration but RFBee (433MHz, 1km) module only have channel configuration. Please refer RFBee (434MHz, 100m) module user’s manual for the configuration and for RFBee (433MHz, 1km) module, please refer to this user’s manual for the configuration.
Parts of configuration for RFbee Module
All RFBee (434MHz, 100m) modules must be configured to same address and same channel to communicate, luckily, by default, they are in same channel and address. Same goes to the RFBee (433MHz, 1km) modules.
Wireless distance of both RFBee module without antenna
RFBee modules are able to communicate even without antenna at a shorter distance. These are the result we get from test in our office. It could be vary with your testing result, so just take it as reference. We do not have an Anechoic Chamber to perform RF measurement test
The test setup is to use 2 two RFBees, one is stationary, another is remote. Both RFBee will be stacked on CT-UNO with XBee shield. The stationary node is program to echo the data it receives from UART (It transmits whatever it receives). While the remote node is being program to transmit a byte of data from 0 to 255 and wait for that byte of data to be echo, verify it with value being transmitted, and show the result on LCD. If there is the value is wrong or no data received within certain period of time, LCD will show data lost. We will take the remote node and move away from stationary node and monitor the LCD.
Wireless distance of both RFBee module with Spring antenna (come in the package)
Solder spring antenna onto RFBee modules.*Spring Antenna should solder vertically for better wireless communication range. These are the results we get from indoor and outdoor test (line of sight), using the spring antenna that comes with the RFBee, you need to solder it. For better wireless communication result check out this tutorial where the distance improved with straight copper wire antenna with length of 17.3 cm.
The possible number of slave nodes for a master node
RFBee (434MHz, 100m) module must be configured to same address and same frequency channel to communicate. Depending on your application and requirement. Let me put in simple phase, what is the different between address and channel? Address is like a name, channel is like phone number. If you call to correct phone number with the correct name, you are able to communicate with the node. But if you call to correct number, but wrong name, the person will still hear what you say, but will not process and further communication is not possible. Yet interference may happen if a node transmit in same channel with different address.
Master node require small modification in order to enter AT mode further to change address or channel of module to communicate with slave node that have unique address or unique channel. By referring to user’s manual, a modified master node is able to communicate up to 200 slave nodes of unique address without interference using same channel. On the other hand, if you need more nodes, considering making both channel and address of each slave node unique, the number can be >5000 slave nodes. 200 (available address) x 20 (available channel) = 5000. Please refer to this tutorialabout modification on master node.
RFBee (433MHz, 1km) module does not have address to configure, it only have channel. Therefore, it is simpler to use. Again, the master node will require small modification in order to enter AT mode and change channel of module to communicate with slave node that have unique channel. According touser’s manual, there is 100 working channels. Please refer to this tutorial about small master modification.
The cost of RFBee module
You need at least a pair of RFBee module for wireless communication.
A pair of RFBee (434MHz, 100m) cost RM 61.50 x 2 = RM 123.00
A pair of RFBee (433MHz, 1km) cost RM 83.75 x 2 = RM 167.50
The cost difference between both pair RFBee modules is RM 44.50
In the conclusion, both RFBee modules have pros and cons. For example, RFBee (100m) can communicate with more slave nodes but the distance is shorter, yet it is cheaper !! So it is up to you!