13.56 mhz Ceiling Fan Control

[Ron L]

Installed a new ceiling fan purchased from Amazon.  As is typical with these Chinese fans, they come with their own RF remote to control fan and led light.  Installed a similar fan last year and it was 433 mhz and was able to read and send RF signals with Tasmota flashed Wemos D1 mini and RF receiver and transmitter.

This new fan RF however is 13.56 mhz and my existing Tasmota RF receiver does not pick it up.  I am seeing Tasmota support for a "MFRC522 RFID Reader" which operates at 13.56 mhz, but not sure it is the same thing as what I need this application.

Anybody have any experience with 13.56 RF signals or MFRC522 RFID readers?  They are inexpensive enough, so may just buy one, hook it up and see if it reads my fan remote hand set.

[Philip Knowles]

The RFID readers are very short range (contactless swipe cards).  As far as I know that’s the only use of 13.56MHz technology. A link to the Amazon item might shine more light on it as it were.

 

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[Ron L]

Attached is the link for the item I purchased.

Amazon.com: ocioc Quiet Ceiling Fan with LED Light DC motor 32 inch Large Air Volume Remote Control for Kitchen Bedroom Dining room Patio : Tools & Home Improvement

You confirmed my suspicions regarding the RFID Reader.  Being short range, probably not what I am dealing with here.  Nothing overly urgent.  I will keep digging.

[Philip Knowles]

I can’t see any mention of 13.56MHz anywhere. Another of their fans mentions a 2.4GHz remote  (Bluetooth I presume) – but I would expect the Bluetooth symbol to be on it.

You might be able to narrow it down using rtl-sdr (or similar)

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[Philip Knowles]

If there’s an FCCID you might be able to get some information from that.

 

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From: Ron L
Sent: 07 September 2023 20:09
To: TasmotaUsers

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[Ron L]

No FCCID sticker on the remote, did not think to take a picture of the controller before I assembled the fan.  I popped open the remote handset and that is where I got the 13.560 mhz as that was on the tin can crystal on the PCB as well as a single DIP IC "DHS16RF".    rtl-sdr  is new to me, though a quick google search and I see where I can hook one up to a Raspberry Pi relatively easy.

[Andrew Russell]

Random google response: "But, I’ve never seen any RF Remotes that operate on 13.560 MHz. Why are you sure it’s a 13.560MHz device? The 32nd harmonic of a 13.560MHz crystal is 433.920MHz, right in the middle of the 433 MHz ISM band."

I would start with a cheap 433MHz receiver module and a cheap Logic Analyser USB module to take a look at what the Remote generates. But it very much depends on what tools you are comfortable with.

IIRC, Tasmota can only handle the common 24-bit RF codes. your fan may have a different packet length.

rtl-sdr hw with rtl_433 sw is very good; with luck it will decode it automatically.

Another option is OpenMqttGateway.

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[Ron L]

@AndrewRussell, Thanks for pointing out about how my device could still be working at 433 mhz.  Like probably most all of us in this group, I enjoy a challenge.  I already have the 433mhz receiver, not really sure if by "cheap Logic Analyzer USB" you mean a rtl-scr hw or something else.  I have found the following rtl-sdr on Amazon and may get it.

Amazon.com: RTL-SDR Blog V3 R860 RTL2832U 1PPM TCXO HF Bias Tee SMA Software Defined Radio with Dipole Antenna Kit : Electronics

That said, if Tasmota only handles the common 24-bit RF codes and I find that my device is working on something other than that - then I assume I will not be able to use a Tasmota flashed device to generate such signals?

[Andrew Russell]

This will be a research project, which may or may not have a successful conclusion. But if you want to pursue it...

This is the kind of logic analyzer I was suggesting https://www.amazon.com/HiLetgo-Analyzer-Ferrite-Channel-Arduino/dp/B077LSG5P2

Logic Analyzer: It will just show the waveform from your 433MHz receiver. Decoding it is up to you, but you will be able to count the bits and compare it with your previous remote. There is a learning curve to getting it working, but it's fun and rewarding!

RTL-SDR: receives off-air, and rtl-433 will attempt to decode it.Hopefully, it will recognize the code. There is no obvious way forward for how to transmit the codes.

OpenMqttGateway - has some of the rtl-433 code in it, and, if you are lucky, may be able to receive and transmit the code.

One thing to look for with the logic analyser - does the remote send the same code every time? Some remotes (eg garage door openers) have a 'rolling code' to defeat cloning. The receiver will ignore 'copy' codes that have already been received, or codes that appear too far from the future.

Of interest:

https://www.youtube.com/watch?v=_gdXR1uklaY  Using OpenMqttGateway with 433MHz devices.

https://pushstack.wordpress.com/somfy-rts-protocol/ Discussion of the Somfy 433MHz signal, which uses a rolling code and obfustication.

Tasmota for non-24b codes? Maybe. I wrote this Berry code to generate Somfy signals from Tasmota: https://github.com/andrew01144/Tasmota-SomfyRTS

Good luck!

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[Ron L]

For closure, @andrew was spot on and was able to work me through my issue. My new fan remote was in fact operating at 433 mhz and while not a standard Tasmota protocol, he showed me how to work around it.  I learned so much because this group has so many talented members willing to share.  Many thanks to Andrew for taking the time to help me.