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A few years ago I bought an SDR and installed it on my home security system. While I was playing around with it I discovered a program or something that allowed me to see the transmissions from three of my local outdoor thermometers.

I'd like to try that again but I can't remember what program it was and I can't seem to find it.


To answer your questions, I can do either windows or Linux. The one that worked was on the Windows machine. The stick is RTL-SDR. About as simple as they come. I am not actually looking for my thermometers. I have a personal alarm (I've fallen and can't get up) that transmits to some base unit. I don't want the base unit. I want to integrate it into my home security system. I have done that before but I need the frequency for starters. That program was slick. I started it and up popped all the transmissions. My security system is here [link](https://github.com/PeteCal/DACSS)

Anybody have any ideas? Thanks in advance

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    $\begingroup$ On Windows? Linux? Which SDR device? Any idea of the frequencies you were inspecting? Make sure you take the tour if you haven't already to see how SE sites differ from threaded forums. The idea is to present a question that shows the research you've done and asks a specific question. Have you searched online for all the usual suspects? Done some research on the specific thermometers you have in mind? $\endgroup$
    – user21789
    Mar 10, 2022 at 16:29
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    $\begingroup$ e.g.: I literally put "sdr inspecting thermometer transmissions" into a web search and got all kinds of interesting hits, including GitHub projects. You will want to narrow these results to some degree based on the hardware you are using. Feel free to circle back here with an edit if you don't get anywhere with your research. Oh, and welcome to Ham.SE. $\endgroup$
    – user21789
    Mar 10, 2022 at 16:32
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    $\begingroup$ clvrmnky. Although I am new to ham, I have been on stackexchange and stackoverflow for years. I didn't think I had to prove that I exhausted all other alternatives. I think I did. As for your search, I have done many variations. There are always many returns. The problem with the internet today is there is just too much out there. I tried many and couldn't get them to work. The list is long, too bad I didn't keep a list. And what I could get to work were just to complex compared to what worked back then. What I was hoping for is someone to say, "try XXXX" it does just that. $\endgroup$
    – PeteC
    Mar 11, 2022 at 2:07
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    $\begingroup$ Can you edit the question so those details are part of it? Comments will often get separated/removed from a question. Because those exact details turn this from a fishing expedition into something that will attract good answers. $\endgroup$
    – user21417
    Mar 11, 2022 at 13:02
  • $\begingroup$ Sorry. Thanks everybody for your efforts. Time to say, "Over and Out". $\endgroup$
    – PeteC
    Mar 11, 2022 at 17:25

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You are probably thinking of rtl_433. It allows receiving and parsing telemetry packets from a variety of devices.

rtl_433 (despite the name) is a generic data receiver, mainly for the 433.92 MHz, 868 MHz (SRD), 315 MHz, 345 MHz, and 915 MHz ISM bands.

The official source code is in the https://github.com/merbanan/rtl_433/ repository. For more documentation and related projects see the https://triq.org/ site.

It works with RTL-SDR and/or SoapySDR. Actively tested and supported are Realtek RTL2832 based DVB dongles (using RTL-SDR) and LimeSDR (LimeSDR USB and LimeSDR mini engineering samples kindly provided by MyriadRf), PlutoSDR, HackRF One (using SoapySDR drivers), as well as SoapyRemote.

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    $\begingroup$ Kevin, that is exactly the program. $\endgroup$
    – PeteC
    Mar 14, 2022 at 16:23
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    $\begingroup$ But with all the searching I was doing I stumbled across a ESP-12 device. It uses wifi to transmit and the circuit card fits inside the personal alarm module. I think I will use that rather then the 433 module. Then I don't need a second SDR dongle. The one I have can stay dedicated to mt 345MHz security system. $\endgroup$
    – PeteC
    Mar 14, 2022 at 16:29
  • $\begingroup$ Here it is a year later. In the end I bought some 433MHz receivers (the superhet version worked the best) and connected it to one of the gpio pins of my RPi. Then I wrote a python program that imports _433.py and pigpio. The personal alarm works inside the house and outside if in range. It sends ytext messages and emails to a list of people when the button is pressed. $\endgroup$
    – PeteC
    Mar 12, 2023 at 20:21

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