Category Archives: SDR

RTL-SDR

How To Keep RTL_433 Alive For Your Home Automation Using Supervisor

14 Replies

I run RTL_433 to push data from several sensors and a motion detector to an MQTT server for home automation.  For some reason as of late it is just not that stable. Could even be a hardware failure with the dongle….I dunno.  I generally just run the program command inside a terminal on the raspberry pi it is installed on and just walk away.  When it crashes I have to log back in the Pi and re-run the command.   Un-cool.

The command I use specifically is this:

rtl_433 -F json -M utc | mosquitto_pub -t home/rtl_433 -l

Again, that pushes data found on 433.920 MHz devices to publish a topic on my MQTT server called “home/rtl_433”.

Continue reading →

Configuring Inexpensive 433 MHz Motion Sensors for use with HomeAssistant

3 Replies

Last week I showed you how you can capture the remote codes for cheap radio controlled electrical outlets and this week the theme is MOTION DETECTORS.  With a properly configured motion detector you can then trigger that outlet.  For example……..when you open the pantry door the light comes on………when you walk in the laundry room, the light comes on……..when someone presses the smart doorbell, the lights come on.  Pretty handy stuff.

Most home automation motion sensors send TWO signals. One when they are tripped and one when they reset.  Most of them will stay tripped for a predetermined amount of time.  Usually for 2-4 minutes or so.   Good idea to know the state of the motion detector BEFORE you buy it.

For example I have a motion detector with a 4 minute reset on it in my garage and laundry closet. That means that both of those lights that get triggered are staying on for 4 minutes whether I like it or not (unless I write some crazy code).

Continue reading →

RpiTX Replay Attack on GE MySelectSmart Remote Control Outlet

4 Replies

Was walking around Target and saw an inexpensive remote outlet which I was pretty sure I could perform the Replay Attack on.

The Replay Attack  is when you record a signal from something and transmit it back to perform the operation.

These devices typically transmit around 433 MHz and have no encryption of any kind whatsoever.  Just a simple transmit burst for on and off functions.

Continue reading →

Spyserver on Raspberry Pi

1 Reply

What’s a Spyserver?  And why would you want one?  Spyserver is a program for a Software Defined Radio (SDR) that allows you to access that radio from anywhere.  It also allows you to share your radio from anywhere and you can likewise share other people’s SDR radios.  Why would you want to do that?

First when the word “radio” comes to mind we tend to think of AM or FM radio only.  An SDR device is so much more than that.  It can literally listen to things from 0 kHz to 2 GHz or so.  That’s EVERYTHING that you can think of that uses a radio signal.   Short Wave, CB, Ham, pagers (yep they still use pagers), Police, Fire, EMS, the Space Shuttle flying overhead (not kidding), the tire pressure monitor sensors on your car, tracking aircraft, tracking ships, tracking weather balloons…………the list is almost endless.

Continue reading →

Common Problem with OP25 in Virtualbox

Leave a reply

I REALLY struggled hard to learn to use OP25 and once I figured It out I made a simple tutorial for myself to recreate on other computers and for others to use.  On my blog it is one of the more active pages and almost every week I get emails from people requesting help getting it working.  This is the page of instructions I made:  (there are a couple more pages that are Raspberry Pi specific but you’ll have to poke around my blog to find them).

OP25 For Dummies – Or how to build a police scanner for $30 (Part 1)

I would LOVE to help everybody but alas, I met a hot neighbor lady walking dogs a few months back and she’s cutting into my geek time!  Trust me when I say that I’m not complaining!

Most of the time I find that many users are installing Ubuntu under Virtualbox in either Windows or on a Mac and this is one of the most common errors:

Continue reading →

A Tale Of Two Decoders – OP25 & DSDPlus

2 Replies

It was the best of decoders, it was the worst of decoders……… As you can tell I’m quite the literate bastard and highly up to speed on my Dickens.

I love digital signal decoding as it is almost something that you seemingly aren’t supposed to do, hence the attraction of it all.   There are several hunks of software that can decode digital signals and each one has it’s strength and weaknesses.  The ones I have dabbled around with are:

There are certainly others, not to mention maybe the most powerful one (but by far the one that requires the most geek foo) is GNURadio.

Continue reading →

DSD+ Trunking Tutorial

2 Replies

One of my favorite programs for decoding digital audio is DSDPlus.  I’ve been using it a couple of years to dissect and decode SINGLE digital signals.  Like for instance if I’m in the airport or airport hotel I can listen to DMR radio where the baggage handlers are talking to each other, or the mall cops are planning how to be real cops.  Or you can hear the hotel staff on their radios which is sometimes really fun.

BUT…….DSDPlus also follows Digital Trunked Radio.  That is where there is a Control Channel which is monitored and then the calls are “trunked” to available frequencies allowing for more users to use the system without confusion.  Also users can be placed into Talk Groups which keeps down the confusion even more.  Entire cities can use one radio system to control municipal services such as Police, Fire, EMS, Public Works, Events, etc.

Continue reading →

ProScan for Uniden Scanners

6 Replies

So I bought the Uniden SDS100 hardware scanner, and I love it.   But it cost $700, and then I added DMR decoding for $60, and NXDN decoding for $50.  So I’m into this in a big way.  The SDS100 is POWERFUL.  It is not a toy by any stretch of the imagination.  It comes with free control software called Sentinel (yeah the download is hard to find on that page).  Sentinel is adequate for managing favorites and reading and writing to the scanner and it is all you NEED.

However I stumbled across this hunk of software called Proscan which looked interesting but it also costs $50.  Where does the cost with this scanner end?  Well, like most programs Proscan has a 30 day trial version so I gave it a shot.  After playing with it for like an hour I knew it was worth the cost so I bought it.  It does NOT disappoint.

Continue reading →