Decoding 433 MHz Devices With SDR

hey everyone now lately i've been in a bit of an rf mood so i've been playing around with radio now i haven't done radio theory for years but i'll probably brush up on that again in the near future and have some in-depth fun with it but um for now i just want to show you a program that i came across to look at little devices that transmit in 433 megahertz sort of frequencies and they include things like weather stations doorbells and remote controls garage door remotes and stuff like that so i'll just jump straight in and show you what what i'm looking at here but here i've just got gqrx running at that at that frequency so you can see these little pulses of rf coming in and down the bottom this program that i'm going to show you how to install it uh decodes some of these for you not all of them it decodes some and tells you what's going on so you can see there's this thing called an acurite 5n1 there's a thing called fine offset it's oregon thin giving um you know weather details and that one's a temperature sensor so it seems that some of the neighbors have a weather station which means that i have a weather station so if i look them up i can see uh here's one of them that's that what is it accurite 5n1 sensor so that was uh that was one of them that came up here acrylic five and one sensor fahrenheit for some reason and uh but we've got metric for wind speed so you know good on them uh another one here this fine offset look that one up so here's the fine offset one just another sort of measuring thing and their gimmicky little controller but this one's interesting because when i was looking it up i also stumbled across the um american fcc whatever that stands for that's their acma basically um does all the measurements of what products can transmit so they've done a few tests on it and that may or may not be interesting but i'm not too interested in that really um another one they've got here that comes in every so often is some here oregon thin blah blah blah and it looks like just a temperature sensor that's probably inside someone's house if you look that one up it's that so i don't know where these are i might have to hunt them down but um that's what's coming in now they're not the only things that that program can decode i found some other things that came up were car tire pressure sensors okay and one of them even had the brand abarth which is a car and i know there's one that lives not too far away so you could in essence log when the car goes past if you really wanted to to do that but i'm just interested in setting it up so what i'm going to do is i'm going to show you just how to go through uh setting it up on a raspberry pi i'm using not this uh black type of one i'm using the blue ones the new electrons because they work these this was dodgy so this is just for show and tell but i'm going to go through the process on here and just show you how to run it on one that has an antenna now i did a video a few years ago setting one of these up and there's the blue one there that that i'm actually using up in the roof and as i said the reason i started youtube was basically so i could log all the notes in case i need them so i'm going to refer to these notes they're still valid in the info of that video now this is just to set up the dongle in general not the program we're going to use we're going to do that second but this this sets it up for using the rtl sdr dongle for other things as well so i'm just going to quickly go through through this setup now it's on the raspberry pi see that bash no marking around apt-get update okay it's the same as this script except it didn't have the git command so i had to um install that myself just um same old way apt-get install git but the rest is the same so i won't bore you with the details okay that's installed now i'm going to get the program and install rtl433 which is to decode all those messages so here it is here rtl433 now i don't want it in this computer i'm just going to copy that link copy link location wget and download that so unzip master zip cdrtl433 same sort of thing just make a build directory go into it cmake.dot and then make then make install so you can make the program without being a root user i did that before just because i felt like it but um to install it when you get to make install you'll have to either pseudo that'll be a root user that's no drill so make that okay the raspberry pi one isn't the quickest in the world of compiling so i'll just edit this out save you the hassle of watching it like i am right now that's installed ready to go except that this doesn't have an antenna and that's a crap adapter anyway so what i'll do is i'll show you how to run it on my existing one that's in the roof on a decent str dongle with a decent antenna so just run rtl underscore 433 that'll think about it as soon as something comes in we'll see it there we go fine offset first thing that came in so apparently it's 21 degrees out there that would be total rain because we haven't had three meters of rain here lux i've noticed this accurite 5 and 1 always sends three messages so yeah sequence number zero one and two here we go fine offset so you can see how quickly they come in around here anyway now i've got a second sdr receiver to visualize this on gqrx so i can see it up here while it's coming in on the 433 program but other things use this as well like the doorbell if i press that you can see where that is okay really strong now don't forget the antennas actually on the roof and i'm down here at this desk so given the strength of that i imagine that the much lower strength of these weather stations means they're not exactly next door to me and i haven't seen any next door so they're somewhere in the neighborhood i don't know exactly where i could go for a little bit of a hunt and see if i could find them so to do that i would need some portable method of visualizing the rf all right so what i've got here i have a nokia phone yes nokia because the battery lasts for a long time you get a week without charging that and i've got the hack rf so with the heck rf and a program called rf analyzer i can just plug that in there fire that up yes you're allowed to use it i can see the signal now this isn't going to get much but i put some velcro on here a while ago for something else so what i might do is just put a bit of velcro on the back of the phone and have a unit like that and it seems that when i went to buy velcro all i got was self-adhesive hook and loop it's velcro so we're gonna see about putting some of this on the back of the phone and stick that to it and maybe go for a wander all right bit of arts and crafts here just uh put that same length as there oh one there all right i'll just put that there so i can still win the antenna up there and sort of get to the camera what the hell okay you guys all right here goes all right portable hack rf portable spectrum analyzer okay now i can go hunting for weather stations around the neighborhood right so i'll just start up the old rf analyzer here and i'm not going to get much with this antenna because it's pretty useless and in reality i'm not really going to walk around the neighborhood and even if i did walk around the neighborhood i've got a cameraman or camera woman or whatever to film it so you just have to trust me i'm not i'm not going to be there with a selfie stick in this that's just you get locked up so anyway i do have the capability to do it but um it doesn't really matter where it's coming from i mean that could be a bit of fun to look i know one of the neighbors up the street is also into sdr a little bit he's got um he's got the capability to receive and i know he's got some remote control power points so you know just power power boards where he's got stuff running off them by remote he's probably suspected that i'm going to decode that just for the hell of it but you know i'll be good i'm not going to do anything to him because he knows where i live anyway um going back to this program here if you have a look what's coming in as i said it's it's mostly weather station stuff but i did have a bit of a look uh over over a day once if you look at the help file for this program you can see you can output in in lots of different formats so one here good old jason i did some logging over a day well one of the things i found interesting was um if you look for tire pressure monitoring system there were lots of these i'm gonna have to make that smaller just to make it fit on here so you can see some hyundai ford a bath spider now i know there isn't a bath car around here it's not a spider and whatever else that is so you can see people's tire pressure as their drive path okay so there's a bit of fun you can have with an rtl dongle and a bit of software on a raspberry pi now given that those messages obviously weren't encrypted they're only simple on off keying messages most of them i could receive it and see people's wind speed and temperature but there's nothing to stop me generating similar pulses and transmitting false data back to their station so that might say oh it's a million degrees or something you know if you're that way inclined i suppose or you could just look at doorbells being pressed that sort of thing so in upcoming videos i'm going to show some stuff in gnu radio as i do it on how to synthesize the actual pulses of these and transmit them and just take it from there and i don't know where it'll go from there but just mucking around so that'll do for now until next time take it easy

Channel: Tall Paul Tech

Views: 70,721

Keywords: 433mhz, sdr, raspberry pi sdr, raspberry pi, on off keying, OOK, software defined radio

Id: Ms5r9o8P6N4

Length: 10min 52sec (652 seconds)

Published: Tue May 11 2021