DIY :- Wireless Chat Using RFM70
DIY: - Do It Yourself
Wireless Data Transmission Wireless Chat using RFM70
RFM70 is a GFSK transceiver module operating in the world wide ISM frequency band at 2400 - 2483.5 MHz. Burst mode transmission and up to 2Mbps air data rate make them suitable for applications requiring ultra low power consumption.
The embedded packet processing engines enable their full operation with a very simple MCU as a radio system. Auto re-transmission and auto acknowledge give reliable link without any MCU interference.
Block Diagram:-
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This is the basic Block Diagram for the project in which you have to catch the data from any device or you can use Personal Computer or Laptop to send the data for that you need to interface the Computer with the project board and here it is Serial Communication as now a days serial port are not available on Laptop you can also use USB to Serial cable and that data is given to the Microcontroller.
For the communication between Microcontroller and RFM70 module you have to use SPI protocol many controller gives the Hardware SPI but in this project we are going to use Software SPI.
Data which is received by the Microcontroller is now transffered to the RFM70 and RFM70 transmit that data in RF.
This is all about the Transmitter and for the Receiver it will do the same procedure but in reverse order first RFM70 Module collects the Data from RF and then on the request from Microcontroller via SPI Command it gives the received data to Microcontroller and the same data now also available on the other Computer or Laptop.
Interfacing PC with Microcontroller
To interface PC with microcontroller you have to use the MAX232 or any equivalent IC have a look at #-Link-Snipped-# for the other details.
Here is the Circuit Diagram for the same.
Microcontroller Section
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This is the Circuit Section for Microcontroller Here I have used Freescale Microcontroller but you can use any Microcontroller. Now if you see that there is Name given to every Pin which shows that pin's Connection.
Now as we are going to interface controller with MAX232 and RFM70 there are CE,CSN,SCK,MOSI,MISO and IRQ signals are used to communicate with RF Module and RXD,TXD to communicate with Serial Port of PC.
Now Before we start SPI Communication with RF Module you must have knowledge of SPI. for that again refer #-Link-Snipped-# for Some basic Information about SPI.
Note:- Remember as the RF module is working on 3.3Volt you must have to choose MCU which is working on 3.3 Volt. Here MCU_SUP is 3.3Volt
RFM70 Connection
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This is the connection detail for RFM70. Now we have to make a software which communicate with RFM70 using microcontroller. For More information about RFM70 and its internal register please refer datasheet.
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