Let Raspberry Pi’s communicate with each other per 433MHz wireless signals

Raspberry Pi 433 MHz

Maybe some of you thought about how to let some RaspberryPi’s communicate with each other wirelessly. For this purpose small 433MHz modules are ideal, which are already available for a few bucks.

Therefore in this tutorial I want to show how two (or more) RaspberryPi’s can “talk” with each other. But do not worry, if you have only one Raspberry Pi, you can do it also.

 

Hardware

  • 2 Raspberry Pi’s (at a pinch only one will do)
  • 433 MHz Transmitter-Receiver Set (US / UK), if both Pi’s should send and receive you need 2 sets
  • Female – Female jumper wires (US / UK)
  • Breadboard (US / UK)

 

Assembling

The set consists of a transmitter (square, 3 pins) and a receiver (4 pins). Both are very small and therefore also ideal for other purposes. The receiver module has two data pins in the middle, from which we only need one.

443mhz 433mhz
 

RaspberryPi Transmitter Receiver
 Pin 2 (5V)  VCC  VCC
 Pin 6 (GND)  GND  GND
 Pin 11 (GPIO17) – RPi Nr.1  ATAD  —-
 Pin 13 (GPIO27) – RPi Nr.2  —-  DATA (to the left of GND)

 

If you have only one Raspberry or you want that two Pi’s can send and receive, connect transmitter and receiver to the same Pi.

 

Preparation

Before we can test the actual software, we need a few libraries. Theses must be installed on all Pi’s that are communicating.
First of all wiringPi is required. If yave you already installed this previously, you can jump to the next installation (if the command gpio -v returns a result, it is installed).

First, we update the packages. This may take several minutes.

sudo apt-get install git-core
sudo apt-get update
sudo apt-get upgrade

Then we clone wiringPi (git must be installed) and install it.

git clone git://git.drogon.net/wiringPi && cd wiringPi &&./build

Now gpio readall should show the pin allocation.
We need a library that simply allows us to send our data via the transmitter and receive it through the receiver module.

git clone https://github.com/ninjablocks/433Utils.git

This library contains corresponding scripts for both Arduino and Raspberry Pi. Now we go to the folder containing the scripts for the Raspberry Pi and compile them.

cd 433Utils/RPi_utils
make all

 

Testing

Now it‘s time to test. To do this, we activate the receiver first. Make sure that you are in the folder 433Utils/RPi_utils.
sudo ./RFSniffer

As soon as a code is received, it will appear here.

Next, we want to send. For this we go to the other Raspberry and run the following command (if you have only one Pi, just open a second shell window, eg by using putty).

sudo ./codesend 1234

The sent number you can enter by yourself. E.g. by using ASCII numbers, a text can be send.

Have fun trying!

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17 Comments

  1. Alper on

    Hi,

    Don’t forget to put --recursive when cloning 433Utils

    Use as below:

    ~/  git clone --recursive https://github.com/ninjablocks/433Utils.git

    I hope this helps

    Reply
    • kate on

      hello!
      I would like to know which raspberry pi version you used . I’m stuck at not receiving and signal using ./RFSniffer.

      Reply
  2. Greensouth on

    Isn’t supposed that you would fry your Pi if connecting the receiver (5v) to your GPIO pin (3.3v) without a divider?

    Reply
  4. Kraft on

    Looking to do this as a project for high school kids. They are new to the Raspberry Pi. Can you provide more details? How do the female jump wires and breadboard fit in? Are there instructions for connecting them?

    Reply
  5. James Morris on

    when I try to compile the code I just get an error that reads:
    “*** no rule to make target ‘…/rc-switch/RCSwitch.o’, needed by ‘send’. stop.
    what am I doing wrong?
    Thanks in advance, James

    Reply
  7. Jörg Michael Günther on

    I can´t compile One who knows why.
    make: *** Ingen regel för att skapa målet ”../rc-switch/RCSwitch.o”, som behövs av ”send”. Stannar.
    WBR
    Jörg

    Reply
  9. Cabi~ on

    Is something like this possible between two RasPi-Zero-W over WiFi or Bluetooth, effectively being able to dispense with a USB cable between a computer & USB gadget?

    Reply
  10. Wilmer on

    Can someone kindly point me to an arduino sketch for receiving? I’m having a lot of difficulty getting an arduino to pick up on the signals sent by the raspberry pi.

    Reply

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