I realise that this is quite an old thread, but i found it a useful source of info when looking for a solution for my 433MHz problem, so I thought I'd share some of my findings...
We have a holiday home in Spain and it has some external 'awnings' that extend over the windows to provide shade from the sun. In Spain these are called Toldos. They operate using tubular motors controlled using 433MHz remote controls – one remote for each awning, three in total. I'd tried all the regular methods to sniff the 433MHz protocol, but none of the standard Arduino libraries would even acknowledge that the remote was sending out any sort of signal. Other remotes, such as garage door openers, PIR detectors etc work fine with my sniffer, so the hardware/software I was using is good.
I eventually resorted to using my sound card and Audacity software to capture the transmissions from the remote controls and this work surprisingly well (I'd tried every digital approach you can imagine up to this point, including a logic analyser, and was reluctant to try the analogue approach but wish I’d trued it earlier).
What I discovered is that when I press either the UP or the Down buttons on the remote, it transmits a timing pulse followed by 40 bits of data. At first I thought that this sequence was repeated 8 times, but I eventually realised that one 40-bit code was used for the first 4 repetitions of the data, followed by a different code for the next 4 repetitions. I later realised that whenever one of these buttons is pressed, the initial 40 bit code is transmitted continuously then the other code is transmitted 4 times when the button is released. When the button is pressed quickly I just get the 'Pressed' code 4 times followed by the 'Released' code 4 times.
The Stop button works slightly differently - only one code is used and this is transmitted at least 4 times and will continue to be transmitted as long as the button is pressed. (in other words, the Stop button has a 'Pressed' code, but not a 'Released' code).
It's actually the 'Pressed' code for each button that controls the awnings. The 'Released' code doesn't seem to serve any function with my awnings.
These 'Released' codes really confused me to begin with, as I when I checked two different bursts of data from the same button using Audacity, I was getting different results. This was obviously because on one occasion I’d picked one of the ‘Pressed’ codes to analyse, but on the second occasion I’d inadvertently analysed a ‘Released’ code. At first I’d thought the analogue capture process was unreliable, but then I thought that maybe some sort of rolling code system was being used. I eventually realised what was going on, but not until I'd spent quite a bit of time cursing the remote control and the PC.
I was able to replicate the transmitted code fairly accuracy using a version of @peashooter's code (thanks!) and this worked well
I’m repeating the ‘Pressed’ code 4 times and it seems to work very reliably.
As well as being able to control the awnings using an Arduino/ESP8266 transmitter, I also wanted to be able to use the existing handheld remotes, so to be able to understand the current position of each awning I needed a way of receiving the commands from the remotes and using them to keep track of each individual awning. This bought me back to the original problem of not being able to find a way to listen to the 433MHz messages from the remotes using any of the current Arduino libraries.
In started delving into the idea of modifying the RC-Switch library, now that I knew the timing characteristics of the signals. At that point I stumbled across this small library:
It has an Arduino sketch that is written to identify the codes that are being transmitted by remote controllers for blinds, so that these codes can then be used to control the blinds using a Raspberry Pi.
When I ran the Arduino sketch it immediately produced results from my Awning remotes – If only I’d found this earlier!
The results it gives are in a “Quad Bit” format, but when I modified the code to print out the raw received codes they were identical to the results I’d obtained from Audacity.
I’m not interested in using a Pi to transmit the codes to the blinds, and this wasn’t needed anyway, as using @peashooter's code I already had a transmission solution. I’m now in the process of fine-tuning the code that tracks each blind’s position based on the commands that are sent from either the hand-held remotes or my transmitter. The position is simply based on time between the start and stop transmissions and the known time that it takes to fully extend each awning.
The primary reason for wanting to control the awnings is that when it gets windy, I want to be able to automatically retract them. I’m using data from a weather station to monitor the wind speed and if it meets the criteria (very strong winds for a short period, or not quite so strong winds for a slightly longer period, then the awnings will be retracted (assuming that they’re extended of course). I’m also automatically retracting them when it gets dark, as it’s easy to forget to do this and a bit cumbersome to walk around and do all three awnings using the separate hand-held remote controls.
Here’s some pictures of one of the remotes:
The brand name on the remote is Gaviota and the circuit board says “Designed by D Team” “DC104/105” “V2.1” and “No.DA288”.
Here are what the awnings look like:
I have no idea what the brand name is on the tubular motors, as they’re hidden inside the mechanism.
Hopefully this saves someone at least some of the pain that I’ve been through to get to this point.