Module to use for frequencies under 300 MHz

Sub-GHz
#1

Hi, I would like to duplicate my garage remote, the problem is that it uses a very low frequency (around 30 MHZ). Knowing the radio integrated doesn’t support it, can you suggest me a module that I can use (connecting it to the Flipper) to use these frequencies?

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#2

That is a very low frequency for a garage. If you don’t mind me asking.

  • Are you sure that is correct?
  • How old is it?
  • Model number?
  • What country?
  • Do you know if it is FM or AM?

I’d use an SDR on a computer to capture it. Then it might be possible to transmit by bit banging a GPIO pin. I can’t say whether it’s legal to transmit there however.

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#3

I had to check the exact model, anyway it’s BFT and it was installed 23 years ago. I don’t know the exact frequency but I’m sure it works with this range, probably for an old protocol

#4

You may have some luck using the frequency analyzer app on the Flipper.

#5

Transmitting by GPIO banging is unlikely: crystal clocking Flipper’s MCU is 32MHz, which leaves only a tick to decide and output a bit. Sounds impossible.
As for legality, it probably shouldn’t be any more illegal than using the original remote.

#6

I can’t speak for everywhere but it would be illegal in the US. People do that type of thing all the time and I’m not saying anyone would get caught or prosecuted. We have a lot of complicated and often convoluted laws though. Experimental transmitters must be licensed, approved, or run by a licensed operator. They also have to meet guidelines on spurious emissions and transmit a call sign.

#7

So, it’s impossible to duplicate a remote with these frequecies, right?

#8

I already tried, being the frequency lower (compared to supported range) it doesn’t appear.

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#9

Never consider it impossible. Instead consider it “not currently supported”. We have lot’s of clever people making add on boards and finding ways to expand functionality. I suspect some kind of additional hardware will be needed though. You might ask the question again or bump the post in six months to a year.

#10

On those frequencies there is the remote control “NICE K2M 30.875 MHZ”. It’s an Italian brand. Flipper does not detect it.