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I've recently bought a ceiling fan (Suilon Cambil) and I wanted to automate it substituting the remote it comes with, with a DIY one connected to Alexa.

Main problem is that I haven't been able to identify the chip (image attached) and Suilon's support only told me that it uses 433 MHz signal.

I've tried researching it and using an Arduino with a MX-RM-5 V receiver, but it doesn't receive any signal.

Any help is welcomed.

chip view

I've finally acquired the rtl-usb Nooelec NESDR Mini2+.

I've tested rtl_433 without any luck (I receive weather stations data from my neighbours but nothing that could be from the remote).

I've also tried using Gqrx to try and see if I could locate the signal around the 433MHz, without any luck eother (although it's the first time I've used it and might be missing something).

Going back to the remote, I saw that the crystal in the PCB is marked as 24.000MHz, so I started wondering, do you know if it means 24MHz or 24000MHz? Assuming it means 24Mhz, is it really possible to send a 433Mhz signal with this crystal? Could be that the support gave me wrong information?

Ok then! Assuming that the transmission is a 433MHz. Is there a way to estimate the exact frequency measuring the antenna? Additionally, would it be crazy to bypass the antenna in the rtl-sdr by connecting a cable between the remote's antenna directly to the sdr-rtl?

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  • \$\begingroup\$ research the patent for the device ... it may contain useful info \$\endgroup\$
    – jsotola
    Commented Aug 27, 2023 at 21:02
  • \$\begingroup\$ it doesn't receive any signal .... how did you connect it? ... what code did you use? \$\endgroup\$
    – jsotola
    Commented Aug 27, 2023 at 21:04
  • \$\begingroup\$ There's a very good chance it's a proprietary chip, or is only sold to companies with huge volumes. As a backup, consider buying an extra remote and using analog switches to mimic button presses. \$\endgroup\$
    – TimWescott
    Commented Aug 27, 2023 at 21:53
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    \$\begingroup\$ That crystal is 24MHz and, yes, it's possible to create a 433MHz signal with it. \$\endgroup\$
    – nanash1
    Commented Sep 15, 2023 at 19:10
  • \$\begingroup\$ Search the product information for an FCC ID - fcc filings have lots of information you may find useful for reverse engineering. \$\endgroup\$
    – Bryan
    Commented Dec 30, 2023 at 19:59

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Well worth trying an SDR with analyser to see if you can just decode the signal. Rtl-sdr and rtl_433 are a good combo in my experience.

I've used this in the past to decode a couple of remotes, and oil meter, and the control for a cooker hood. Once decoded it is then fairly simple to control from a microcontroller.

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