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  • Writer's pictureThe Arithmancer

Sniffing RF Transmission Codes

In order to control any RF device in the house, you need to reverse engineer the RF signal generated by the remote control.


Items needed:

* LCD Display (I2C enabled)

* 433MHz and/or 315MHz receiver


First of all, a few comments on RF. Here is a primer on how the radio spectrum works. For the purposes of this project, you need to know two things about the radio spectrum. Firstly, 433MHz and 315MHz are the two standard frequencies that all domestic remote controls work on. 433MHz tends to be the standard used in Europe and the US while 315Mhz is the standard in China. As a result, gadgets come in both flavours so you may want to buy a receiver for each frequency and build the below circuit for each frequency.


The LCD I link to above already comes connected to the I2C circuit which makes connecting it very straightforward. The SDA (data pin) of the LCD goes to Analog pin 4 on the Nano and SCL (the clock pin) of the LCD goes to pin A5 on the Nano. VCC and GND are linked to the 5V and GND pin on the Nano respectively.


If you want to connect a 9V battery, rather than powering the Nano from the USB, you also need to connect the battery +ive to Vin on the Nano and battery -ive to GND on the Nano.





That's all there is to the circuit. Then download my code which can be found in my github account here. Once installed on the Nano, you're done.


Now for the code. There are two main components to the code, you will need to understand. The first is how i2c works to communicate with the LCD display and the second is how the RF code works.


First make sure both libraries are installed. For the liquid crystal display, I recommend downloading this library (LiquidCrystal_I2C). TBC


#include<RCSwitch.h>
#include<Wire.h>
#include<LiquidCrystal_I2C.h>


[Include video showing how to do this]



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