Candle - signal Hub - A universal 433Mhz signal detector and cloner

  • It took three weeks to build, but here it is: a device that will easily connect almost any 433Mhz device to your smart home.

    The 433 Hub can do two things:

    • You can teach it a signal, and from then on it will be able to detect it.
    • You can teach it a signal, and from then on it will be able to replay it.

    Both of these features come in 'single signal' and 'on+off" versions. So for example:

    • You could copy the ON and OFF button from a remote for your 433Mhz sockets, and from then on switch the socket from your smart home controller.
    • You could teach it to detect window sensors that have both on and off states.
    • You could teach it to detect the alarm signal from a wireless smoke detector.

    For each signal that you teach it to recognise, a door sensor will be presented to your controller.
    For each signal that you teach it to replay, an on/off switch will be presented to your controller.

    Signals take between 8 and 28 bytes to store, depending on complexity and if they are simple or on+off signals. This means an Arduino Nano can store between 20 and 60 signals in just half of it's eeprom (512 bytes).


    • Arduino

    • 433Mhz receiver & transmitter

    • Touch screen (optional, recommended)

    • OLED screen (optional)

    • Keypad (optional)

    Here's the version that uses a touch screen.

    Here's a version that uses a keypad.
    With a 12 button keypad you can easily replay 10 signals. The last two buttons are used to navigate and make selections in the menu system.

    You can also trigger the learning sequences from 4 virtual buttons that the device creates on your controller (detect simple, detect on+off, replay simple, replay on+off).

    It works best if you use the touch screen. Using the menu you can delete the last recorded signal, or delete all recorded signals.

    It's designed to work with the upcoming Candle privacy friendly smart home, and the Candle Manager. More on that later this year.


  • @alowhum So this can act as a kind of learning remote, correct?

    Nice work by the way.

  • Exactly.

    And a learning detector at the same time.

  • The touch screen code is now also available.

  • Something I had hoped actually works: it can also copy IR (infrared) signals!

    Settings need to be slightly different, as IR signals are 'slower' than RF signals. Changes I made to the settings are:

    #define MAXEDGES 100            // instead of 400                    
    #define GRANULARITY 100       // the default settings of '50' also work, but IR signals need less precision.
    #define MAXIMUMDURATION 66000
    #define MINIMUMSILENCE 66000

    It doesn't recognise things perfectly, as IR signals don't seem to repeat themselves in the same way. You may have to press the button a few times before the signal can be copied.

    I also haven't tested if transmitting the signals actually switches IR devices on and off.

    An example:

    00000000 > 0
    11110111 > 239
    00010000 > 8
    11101111 > 247

    • It can now handle even more 433 signals.
    • Slight code simplification

  • Probably a bit of a noob question, but if I don't have any of the optional items, can I still use this? Will it just save the RF commands until it can't save anymore?

  • @Homer yes

  • @alowhum said in Candle - signal Hub - A universal 433Mhz signal detector and cloner:

    @Homer yes

    Thanks, and thanks for your private messages!

    I managed to build a rf433 sender which is connected to wifi and is outside of the Mysensors environment, and it works, but I can't get my controller (Vera) to communicate with it. This looks like it should work perfectly for what I want it to do!

    Thanks for sharing!

  • I am having issues with the device I made myself which doesn't use this code, so I have decided to give this project a go. One problem though... I copied the sketch from you link, and even without any changes or alterations, the sketch doesn't compile. It gets to line 468 and says "detectedMessage" was not declared in this scope.

  • Please ignore the above.... I don't know why but I just tried it again and it compiled immediately.

  • I just worked out what I did! I had commented that I didn't have a touchsceen and that caused the error. I thought I should do this as I don't have one, but I guess I'll have a go at uploading the sketch as it is.

  • Thanks for the feedback. Let me know if you have any issues and I can try to fix them.