Decode 433 MHz signals w/ Arduino & 433 MHz Receiver
Today I’ll be showing you how to read 433 MHz codes. This tutorial was made to complement the Voice Controlling project which needed 433 MHz Unit Code Values to control the wireless switches. Since I’ll be getting my own apartment, a lot more 433 MHz RF home automation tutorials will probably soon come up! If you want to know how to read 433 MHz codes using a Raspberry Pi, go to this post!
Contents
Hardware Requirements
- Any Arduino(I used an Arduino Nano clone)
- 433 MHz receiver(Any type of 433 Mhz receiver should work, but for this tutorial I used a 4 pin variant)
- A breadboard
- Some jumper wires
- A 433 MHz transmitter(I used a 4 channel 433 MHz transmitter Remote)
Connecting the 433 MHz Receiver
As you can see in the picture, my 433 MHz Receiver actually has two Data-pins. Why it has two pins I don’t exactly know, but a possibility is it is used to easily connect two output-sources, or two different Arduinos. In this project however we will only need to use one of the pins. I used the one closest to the GND-pin.
| Arduino Pin | 433 MHz Receiver Pins |
|---|---|
| GND | GND |
| 5V | VCC |
| Digital Pin 2 (D2) | Data |
It’s important to know that if you are using an Arduino Leonardo, you should be connecting the Data pin to Digital Pin 3(not Digital Pin 2!).
Because we will be using “interrupt 0”, the Digital Pin you should connect is actually different between different Arduino models. If you are not using an Uno, Nano or Mega, Go to to this site to check out which Digital Pin you should use.
Most people will be using Digital Pin 2 in this project however.
This is how it looks like connected to my Arduino Nano
Getting the RCSwitch Library installed
To make the 433 MHz receiver to work with your Arduino, you need to download a library called RCSwitch.
You can download RCSwitch directly from their official repo:
https://code.google.com/p/rc-switch/downloads/list
After you’ve downloaded it, you should have a zip-file. You need to extract it, and move the extracted folder to your Arduino libraries folder.
If you don’t know where the Arduino libraries folder is, open up the Arduino Software and go to File –> Preferences. If you are on a Mac, it’s Arduino –> Preferences.
Here you should see the Sketchbook location.
In my case my libraries folder is in /Users/Prince/Workspaces/Arduino/Arduino_Training.
Now to clarify, I should move the extracted RCSwitch folder to:
/Users/Prince/Workspaces/Arduino/Arduino_Training/libraries
To finish up the library installation, exit and reopen the Arduino Software, and now you’ve successfully installed the library!
Uploading the code
The code we will be using to read the 433 MHz RF codes is actually located in the library as example code. To open up the code in the Arduino Software, press the “Open”-button, then press: libraries –> RCSwitch –> ReceiveDemo_Simple
Now the code should appear in the textfield. Now connect your Arduino to your computer and upload the code!
Reading 433 MHz Codes
I used a simple 4 channel 433 MHz Remote to send some example codes to my receiver.
Open up Serial Monitor, and set the right bottom list to “9600 baud”. When you then press the buttons on your 433 MHz transmitter remote, the received 433 MHz RF codes should then be printed!
Now in my case you see values ranging around 16738081- 16738088.
So this is how you read 433 MHz codes using an Arduino & 433 MHz receiver!
If you have any questions feel free to ask me by using the Contact page or by commenting below.
Thanks for sharing, I have exactly the same receier and the same remote. But in my case remote is blank I mean no buttons are programmed, what did you use to insert code in it ??
thanks.
If you have the same remote, then the codes should be preprogrammed. Did you install a battery into the remote?
Hi, i need to use the servo library with a 433mhz rf and i cant mix the virtualwire and servo librairies because they both user timer1… can i use this library with the servo? Is the interupt 0 or 1 as someting related to the timer1… im new to arduino and the web is hard place to find help with arduino, lot of old stuff out there. Thx if someone can help me
Very interesting. However there a re a number of 433 MHz transmitters that leave no trace on ReceiveDemoSimple. I guess there just are some codes it doesnt recognise, but then also doesnt recognise them as ‘not recognised’:-)
I have one or two transmitters in which e.g. th eON button leaves no trace on the program output while the OFF button does
Hi Ed, how did you manage to fix this? The same is happenig to me! Thanks!
Hi Ed, how did you manage to fix this? The same is happenig to me!
same with me..
Hi, thank you for this very intersting tutorial 🙂
Having no success in decoding 433 signals with a Pi, I ordered and just receive an arduino Nano.
I installed the library so th I can see it and include it and compile ReceiveDemo_simple with no errors.
I use the same 4 pins receiver and (look) exactely the same “4 channel 433 MHz Remote” as on the photo.
Nothing comes out the monitor 🙁
The Nano is working fine with the simple ‘Blink’ program.
My question :
Do you think It should word with my version of the Nano which is ehanced (ArtMega328) ?
Are the clocks th same ? (I’ll try to find this answer on the net 😉
… However the receiver shows zeros ans ones with an osciloscope nicely organized when pressing the remote button…
OK.
I finally have made myself a working sketch for Arduino that reads 433MHz codes in a fairly reliable way :
http://mgrigaut.free.fr/arduino/MyReceive_Jolly2.ino
Michel, that is a great piece of code. I had to alter the pulse cutoff a bit from 900 to 600uS but then it worked fine.
Just a question: my results is as follows:
Found Header : 27 bits word
001000000000000000000000001 => 1000001
Found Header : 27 bits word
001000000000000000000000001 => 1000001
I dont see immediately how you translate the 27 bit code into the 7 bit code?
solved. it was pure coincidence it was all zero’s and 1’s . The number on the right is the hexadecimal number
Hi.
Your code works for me.
But how do I know, what code the remote has? Finally it looks like that:
Init : Start decoding
10001
1
61
1
5
107
1
5
101121
3
Did you ever figure this out? Thanks
what does your code do?
I have the similar result. What is the decoded result(code)? where do we start to read (between what numbers)? Thanks.
i used this code and it works but it just keeps printing out numbers. whether I press a button or not I just keep getting a bunch of numbers
This method will work in most cases. However the sniffer program sometimes has problems understanding the code that is being sent by a remote and then you need some more digging.
Remember that a lot of Remotes adhere to protocols that are known and you might be able to find it on internet or judt make it up from say the switches on your dvice
Doesn’t work… no reading of “even garbage”… is there any regulation on the Receiver ? Garage Remote control is the same of your picture…
Cool, works with one of my 433-Remote-Controls (like yours). Does it mean I could also connect stuff like this? http://goo.gl/46NlJW – but how can I tell the Arduino to act when the sensor is active – I mean how can I “decode” the lines in a way Arduino knows it’s from this device and not from another?
looks like there is 4 hardcoded codes for the remote many many secure 😀
I have unzipped to ARDUINO/Libraries/rc-switch-master
but then the Arduino IDE complains about the name format the minus signs had to be removed ?
then when compiling the error
ReceiveDemo_Simple.pde:7:22: fatal error: RCSwitch.h: No such file or directory
compilation terminated.
came up
Arduino is nice but the handling of libraries is to hard to understand for me
these libraries have to be on a very special location ?
a library is just a text file that is inserted at compiling time ?
so i do not understand why I always end up whit the above error
this is higher physics to me…
use the latest release instead of the master-branch
and name the rc-library folder just “rc-switch”
use a board like “arduino uno” or “arduino nano”
some boards are very special in handling interrupts, therefor they are not supported by all libraries
for example rc-switch does not support attiny at the moment
hello
How I use a 375MHZ control?
As long as the receiver is 433MHZ tuned too
Hello 🙂
I have the same receiver and the same 4 channel remote. And when I try to read the values from remote, I get just one value. I can read just one channel. And that’s the button c. Do you know what could be the reason for that ?
Hi, can i plote these recived frequency in transmitter module if i can plz send codes for that….
Thanks for the concise walkthrough. Worked a treat for me.
Thanks for this information, worked like a charm!
thanks a lot, very useful to me, cheer
The other buttons are not programmed, you can do it this way:
How to Program:
1. Press the two top buttons until the LED flashes – it takes around 3 seconds.
2. Place the cloner remote and the original remote close together/side by side so that they are touching.
3. Press a button on your original remote in the same time and one of the buttons on the clone remote and hold until the LED on the clone remote flashes steadily. (The Blue LED will first flash 3 times quick, then stops for a second, then flashes steadily for successful cloning).
4. Now programming is successful! If you want to program more buttons just repeat steps 2 > 4. It’s that easy! To reset the remote simply start again with step 1.
What I would like to know: How can I programm the buttons with my own code using an Arduino?
Its is possible to receive 315MHZ signal on 433MHZ Receiver?
Not possible, each receiver of this model is tuned to a specific frequency
make an antenna
http://www.instructables.com/id/433-MHz-Coil-loaded-antenna/
MULTIPLE TRANSMITTERS (3pc) 1 RECEIVER (caps cause easier to find for others, just in case)
I have a setup with 3 arduino’s, each equiped with a 433mhz transmitter and an LDR. The LDR triggers the sending of data and stops again after a 4s delay.
Then there is one arduino with a 433mhz receiver and a midi shield.
Once a transmitter is triggered it sends data to the receiver and the receiver triggers a MIDI command to a MIDI interface (Atm i use MIDI for troubleshooting but eventually it will trigger a command on a MIDI device.)
The codes are running on all devices and i get signal from each transmitter. Except when I turn on all of the transmitters. I have tried sending bigger numbers that are more spread from eachother and i tried giving each a different protocol number.
Still no succes. Next up is giving each a different PWM/pulselength.
All the transmitters and the receiver have an antenna and the arduino in use are Uno’s
Would really appreciate the insight or nudge in the right direction.
Hope someone has a solution 🙂
I found out why it wasnt working.
I was using an if else statement that would send a trigger if a message from the transmitter was received. for instance:
mySwitch.send(5396, 24);
In the demo sketch of RCSwitch.h the else command contains the line mySwitch.send(0,24);
This made hat all the transmitter were constantly sending a zero. I canceled these lines of code and everything is working now! 🙂
hooraay!
RC Switch library works well with my arduino with 2 of my remotes but Not with a 3rd one. All are 433 MHz. Any idea why? Thanks
for me it was that they were all sending a mySwitch(0,24); command. That caused interference and no response from the receiver. In my case. Check my solution ^ if want my code, let me knwo
Como faço para comandar 04 leds via RF 433Mhz com arduino ao pressionar e soltar botão ?
HI
is it possible to interface 3 transmitter each on different Arduino , with one receiver .. \\
I was thinking of implementing 3 transmitter with 3 receiver with different frequencies but idont find any module that comes with tunable feature …. so if any one could help please help ^_^
is it somehow possible to code this cloning remote from arduino? I don’t have a remote to copy from.
Hi hugo,
yes it is. I did it yesterday. You can do it with the transmitter from XY-MK-5V or all other 433 MHZ transmitter. Method how to teach your remote depends on your model. But you can try it like this.
Press the buttons “A” and “B” or “1” and “2” together until the led ist flashing for a few times. Then leave the “B”-Button and in the next step you push the “B”-Button again for three times (slowly). Then leave the “A”-Button, too. No you have cleared all Codes of the remote control.
Step 2:
Send the signal wich you want to send continually with the transmitter from the Arduino. Hold the remote control very close to the antenna from the transmitter. Then press this Button on your remote control which you like to teach until the LED is flashing for approx. 3 times. Then the LED stops for a while and after this the LED is flashing continuously. At least you can leave the button from your remote control.
This is the scheme of my remote control. I think the scheme is very often the same. Maybe you have to play with the times.
Hey guys,
I have another Problem. I can´t receive no signals with my receiver XY-MK-5V in combination with my Arduino uno. I tied the rc_switch and the VirtualWire library. I can´t receive anything. Then I tried the sketch from Michel. Unfortunately nothing happened. The next idea was to connect the data – Pin with the analog Pin A0 form my Arduino. And want to display the Value on the serial Monitor. The value of the INPUT is always alternating along 430. When I press a button on my remote control nothing is changing.
So my first question is. Why doesn’t work my receiver? In so many chats and tutorials it is so simple to receive such a signal. And I tried so many ways and nothing, absolutely nothing is happening.
It would be so great if somebody could help me.
Thanks a lot.
graet article
Hi there,
Thank you for a great article.
Reading through it I have managed to set up rcswitch on an Arduino Mega and wants to decode a signal from a remote to control some rf sockets from the Arduino.
When decoding the signal it has slight variations even if I press the same button. This is also what you describe when you write: “Now in my case you see values ranging around 16738081- 16738088”.
My question is: why does the signal vary and how do you know which variation to chose to transmit from the arduino? I thought the signal would always be the same when the same button is pressed.
Note: the remote has channals A-E. For each channal there is an on/off button.
Hi,
i am very interested by this article.
i have at home a hot (for winter time) or cool (summer time) system.
Each rooms has a remote control (with a zone number)
Do you think i will be able to catch the RF Signals “on” or “off” from one RF remote to be able to reproduce it with pi ?
I heard that some remote control use rolling codes that can’t be reproduce with pi.
Do you know how can i know if my remote use rolling code or not ?
Thanks for your help.
How to use decoded value (1937316) to send , thanks
mySwitch.send(“111011000111110100100”);
Thanks for this, your code has been the only one to show any sign of life for my Aleko gate opener remote. One problem is if I use debug I see lots of 433 information. When I press my remote in debug and normal all i see is one digit or maybe three no “header found”. i think it is something in the Code timing. What could i adjust?
In this tutorial I ll show you how to use an Arduino to decode signals from RF remotes, and re-send them to remotely control some mains switches and a garage door.
Hi How I can reproduce a 3 secs press remote control button with code ? Should I use a for loop and mySwitch.send method inside the loop ? Tx.
what’s the meaning of protocol ?
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Can i use nodemcu esp8266 ?
Thank you very much!
I am so great full for this post, you are awesome
Some helpful facts: Summary (April 2020) on configuring RFSniffer on Raspberry Pi
Since I also have had difficulties in recieving my first telegrams from my 433 MHz remote, I fell the need to give some hints
I had to collect all kind of partly outdated info from some forums. By writing this for you I want to save you some time to reach your today’s goal to see the “Received 123456” telegrams in a normal given time.
Software:
– there no need do install WiringPi as it is already present on modern hardware. Gordon’s website drogon.net won’t reply.
-Installing 433Utils is still needed, don’t forget –recursive parameter
– stick to the port number 2 in sourcecode, that’s correct for GPIO#27 That’s Pin 13 on modern Pi
use ‘ gpio readall ‘ as help
– no need to experiment with the pulselength parameter. It can be passed to RFSniffer. It had no effect on the quality of my results
– setting GPOI port 2 to tristate is correct, the pullup resistor. Use shellcommand ‘gpio mode 2 tri’
– in RFSniffer.cpp method myswitch.available()
always return false IF NO MESSAGE IS BEEING recieved, which is true for 99.99999% of the time spent in the loop. So that’s O.K.
Hardware:
-connecting a reciever to +5Vcc that gives a +3.3V to port 2 doesn’t harm your Pi. Add a 1K resistor to fell better. (No warranty besides me to this!)
-the reciever I used was absolutely deaf on both ears, even after I outfitted it with some loop antenna ~1 inch length: it still didn’t listen to my remote
-actually I had to go sooo near to that thing to see first success: Really close, we’re talking of 2-3 inches max!
-finetuning: after I tuned the reciever with a precision screwdriver I was able to extend the range to 3 meters !! That’s still not enough for most home application – but hey – the whole set costs €3
-using your multimeter to measure the signal coming out of the identical datapins from the reciever is a good idea. So you can be sure wheter you have issues on HW -or SW. You don’t need an oscilloscope for that.
My reciever showed some signal as I pressed the remote button:
V~ (AC) was 1.0V. I added some driverchip to enhance it to 1.3V, but it will normally work. V~ will be 1.0V * 2 * sqrt(2) -> 2.8 Vpp (peak to peak). This would only be true for a sine wave, we dont have this here. But for comparison it might help.
This V~ AC measurement strongly depends on your ASK (Amplitude Shift Keying) reciever and on how many “ones” it will recieve from the remote. The puselength of my remote is 1.2 ms
I think that’s the latest info I’ve got for you today I wanted to share,
enjoy, have fun and success
Mike
——————————-
equiment used:
Raspberry Pi 3b running Raspbian 4.19.11
433 module: MX-RM-5V 080408
remote control set: brennenstuhl RCS 1000 N
comments for 433 send
————————————–
it was much easier to get the sending module running than the reciever. Most tutorials tell you to first set up the recieve module FIRST in order to get the codenumber sent by your remotedevice. This is afaik not the only solution – I did it the other way.You can use the manual of your remote control set to find the neccessary parameters for the send. I hacked into my own device by trying some codes and succeeded very fast. By examining the very good manual of brennenstuhl the homecode was quickly found by setting the DIP swiches all to on -> “11111” first parameter was found. Then 3 for the third wall plug and 1 for “on”. You hear “click” Heureka. And you’re done!
example from above:
433Utils/RPi_utils/send 1111 3 1
Hi, does anyone know any IDE library for managing/decoding 868mhz signals (I have a receiver, but I could not find a library for it) thanks
Hi Prince, how do you made to have codes on your remote? I have an universal remote controller with 4 buttons but they are empty. How do I manage to assign codes to each button without other remote controllar? thanks
I tried it, nothing received. Same receiver as in the tutorial (I tried two of them to be sure). Arduino Uno, then Arduino Uno WiFi Rev 2, nothing worked. Tried on both data pins. Measured twice, if the contacts are OK. Both simple example, then advanced too. Same sender as the one in the tutorial. Tried my PIR movement sensors too. Cannot imagine what have I done wrong…
Great job. It works fine.