Problem reading 433mhz signals

Hello again

So I’m trying to use Blynk to open/close a garage door. The system works with 433.92 mhz signals. My plan is to link a transmitter to a NodeMCU and put it next to the garage receiver, using it as a wireless remote. The main problem is I can’t read any signals from the garage remote. I’m using the rc_switch library with one of the examples code. I can upload the sketch to the board but nothing would show up in the serial monitor after pressing buttons on the remote. I’ll post a few pictures below with my circuit and the parts I’m using.


Here is the code I’m using:

#include <RCSwitch.h>

RCSwitch mySwitch = RCSwitch();

void setup() {

void loop() {
  if (mySwitch.available()) {
    output(mySwitch.getReceivedValue(), mySwitch.getReceivedBitlength(), mySwitch.getReceivedDelay(), mySwitch.getReceivedRawdata(),mySwitch.getReceivedProtocol());

I’ve also tried using other pins, but still no result.

Also, here’s some info about the garage door/remote

Thank you

//I also tried changin the VCC pin from Vin to 3V3.

You’re using the RC Switch ReceiveDemo_Advanced example.
I don’t really understand what the “output” part of the RC Switch command does. Personally always use the ReceiveDemo_Simple example and this is much more logical as it users serial print commands.

I also use this library:

The hardware you’re using is okay, but I prefer the type that has a crystal on the board rather than a tuning coil.
Like this:

However, the receiver you’re using at the moment should be fine for testing. If you still can’t get anything out of RC switch you may need to try connecting your 433 Rx to the sound card of your PC and analyse the codes that you’re getting.
This thread on the MySensors forum explains more about it, along with a post from me about how I managed to decode the 433 signals for my blinds:


1 Like

Thank you for your reply @PeteKnight

The code I’ve posted is indeed the example sketch ReceiveDemo_Advanced, but I have also tried using ReceiveDemo_Simple without getting results.Maybe I’m not getting the pins right? I’ve read a few tutorials about receiving RF signals and most of them seem to use pins such as 0,1,2,3,etc instead of D#. However, I have also tried the following line in my code “mySwitch.enableReceive(15);” (thinking that 15=GPIO15=D8 on the nodemcu, correct me if I’m wrong) but still no luck. Does the reicever need an external power source? I have the Vcc/GND pin connected to the Vin/GND pins of the NodeMCU, would that be a problem? I have also tried using a 9V battery to power it, having a common GND with the NodeMCU…same problem. I should add that I used 2 remotes, the original that came with the garage door, and another one that came from a system added afterwards to the garage door, both working at 433.92mhz.

Also, the receiver would theoretically be able to read signals from a car key’s central locking, right?
I’m starting to think it might be broken… is there a way to troubleshoot it? Maybe using another mcu with the transmitter and tryng to receive the signals from that one?

//I have also tried the ‘ProtocolAnalyzeDemo.ino’ example, still no output

That’s correct.
I’m not a fan of using D numbers, I prefer to use GPIO numbers.
Some GPIO pins aren’t suitable for use with sensors, and GPIO15 isn’t a great choice. See this thread for more info…

Provided you connect it up correctly, this hardware is pretty-much bulletproof. Powering it from 5v or 3.3v on the NodeMCU works fine for me.

I think the issue is that RC Switch just isn’t recognising the 433MHz commands, so isn’t producing any response. Exactly the same thing happened for me and I ended-up doing the Audacity thing, but in the post I made to the MySensors forum I provided a link to another utility which did work for my particular remote transmitter.

Car remote key fobs generally tend to use rolling code systems and you won’t get any joy trying to listen to them with RC Switch.


@PeteKnight so after pushind the open door button for about 100 times and not succeeding reading the signal, my remote also desynchronised. The garage door knows I’m sending the signal from the remote but I can’t open the door. I’m assuming the remote sends different signals every time(for security reasons) and I pressed the button too many times, causing them to ‘desync’. If this is correct, wouldn’t it be theoretically impossible tryng ti open the garage door with the signal I’ve read from the remote? As this is different each time

I doubt very much if the remote uses a rolling code system. If it does then you should be able to detect the code using the 433 receiver you have, but obviously repeating the rolling code sequence is extremely difficult, if not impossible.

Is it possible that the battery in the remote needs replacing?
Most receivers have a pairing button, usually doubling as a way of clearing the stored remote codes.

Have you tried the sound card and Audacity solution yet?


Yes, I have tried replacing the battery. As I said, the module receives data from the remote (it has a digital display that shows when data is being received). There is a way to reset the remote in the user manual, I will try it asap.

I have’t tried using the soundcard yet, I’ve had a pretty busy week and I’ll try it as sion as I get the remote to work again.

Hi, there is nothing wrong with your hardware, you just trying to sniff a not supported protocol from this library, if you do by hand, not library it will work.

Hi is there already a sollution?
I have same isseu, simple 433 light switch not detected. no result.
sending works only the resieve part

@PeterS I’d suggest that you create a new " need help with my project " topic, and provide as much details as possible.

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You need a sniffer to catch the code of your remote before using it in your blynk sketch

My code looks like this

//************************* 433Mhz Settings *************************//
#include <RCSwitch.h>
RCSwitch mySwitch = RCSwitch();
#define PACKET_LENGTH 24 //length
#define SWITCH_1_ON   1361    //room1
#define SWITCH_1_OFF  1364    //room1
#define SWITCH_2_ON   4433    //room2
#define SWITCH_2_OFF  4436    //room2


Hi, i used advanced example from RCSwitch
I connected the data from my 433 receiver to port 2 of my arduino nano.
But no result in the serial, i also used another libary called 'NewRemoteReceiver.h. and here i recieve a signal. So HW looks fine and wire is fine. But i need RCSwitch for the more functions it gives but then the simple receive needs to work first.

1 Like

I assume you are using

//*************** 433 Mhz init ***************//
mySwitch.enableTransmit(15);//pin D8 nodemcu
mySwitch.enableReceive(RxPin); // Receiver on interrupt 0 => pin D3 nodemcu
mySwitch.setRepeatTransmit(15); // Optional set number of transmission repetitions.


I only use RX now

//*************** 433 Mhz init ***************//
mySwitch.enableReceive(0); 0 is pin 2 on board

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I don’t think that RC Switch is going to recognise the signals from your Klikaanklikult/Trust transmitter unless you add a custom protocol.
According to this documentation, they either use a 132 bit protocol or a 50 bit protocol for older devices…

RC Switch doesn’t generally recognise strange protocols like this.

You could use Plight on a Raspberry Pi to decode the signals, or the sound card and Audacity method (which works very well).
Once you have the protocol information then you could write your own code to listen for these transmissions, or add the protocol into RC Switch.
If you want to emulate the protocol (mimic the remote control) then it’s much easier to do that, as described in some of the links I’ve posted earlier in this topic.


hello friend, if you need to control something with rf 433
I recommend you
EV1527 module or also called Rx480 has 4 digital outputs, it is super easy to use since the same module is responsible for linking controls of up to 4 buttons, it is the same RF 433 communication protocol used by sonoof products.