General Question

vox's avatar

How can I use an RF signal to trigger a macro on my computer?

Asked by vox (23points) March 21st, 2017

I have gqrx app connected to RTL-SDR dongle. I am able to tune into and hear as audio specific RF frequencies, such as my car keys at 315 mHz. I use Keyboard Maestro to trigger lots of macros on my computer. How can I capture this audio on my Mac and link it to trigger a macro or keypress when car keys are clicked?

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7 Answers

ARE_you_kidding_me's avatar

Do you know any code? I have used that same RTL dongle for projects on a pc but not mac. You’ll likely have to write a program to do this.

CWOTUS's avatar

Welcome to Fluther.

Check out the functionality of If This Then That at

I don’t know about your specific case, since I’m not familiar with that sensing hardware (or with the Mac in general), but there are apps for “connected cars” at ifttt, so there may be something you can use there, or build a script based on something that your car keys can send to the computer’s dongle and be received there.

Alternatively (but less likely, I think), you might be able to adapt or write something using the scripting language of AutoHotKey (, but again, it all starts with reading the input from your car keys, and that’s the part I know nothing about.

vox's avatar

I do a little Javascript, and can figure out Applescripts for macro triggering. I can use Soundflower as an output channel, but I’m not sure how/where/what utility will “read” that there is (1) activity on system audio and (2) that it’s of a certain frequency…

vox's avatar

The problem with is that I need to initially detect the audio at a certain frequency first, and then send that as an event trigger somewhere. It could go to IFTTT, but that’s not the link in the chain at issue here yet. Thanks.

ARE_you_kidding_me's avatar

You’re going to have to code it. Any DSP experience? Some of the RTL SDR programs are open source. I’d probably start there.

vox's avatar

DSP experience? Assume you mean this:

No experience, no. Not sure where to start.

Was looking at this, but wasn’t sure if it was appropriate:


ARE_you_kidding_me's avatar

Digital signal processing, it can be done with software too. You’ll likely have to do some. People have paired the rtl dongle with raspberry pi modules. That’s another place to look.

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