I am unable to receive any signals from my 433Mhz remote. What am I missing?
The setup: Arduino Uno with 433Mhz receiver breakout board (link), powered with 5V from the arduino, GND connected, data line connected with pin 2 from the Arduino (interrupt 0). I run the example sketch "ReceiveDemo_Advanced" from the standard-library "rc-switch" by sui77 (link). This sketch logs received signals with rawdata to the serial log. I know it works, because another remote (other company) shows up in the serial log.
The remote is the Trust Smart AYCT-102 (link). I bought it from amaon (link) where it states in title, that it's 433 Mhz. I know it works, because it turns my Trust Smart Built-in Switch ACM-2300-HC (link) correctly on and of.
But my Arduino is not receiving anything from this Remote. Not. a. thing. No reaction at all in the serial log! Maybe it sends on a different frequency? But when I open the remote, there is a crystal on the pcb which is labeled "433A". Looks correct.
The Trust Smart remote probably uses an encoding that the receiving Arduino code does not recognize. There are infinite possibilities, of which valid rc-switch codes are an insignificant fraction.
This tutorial shows you how to analyze an unknown transmission protocol, using a simple receiver and Audacity.
thanks a lot for your remarks! They pushed me in the right direction
I thought, that even if my remote has a different protocol, I should at least see some bits with the rc-switch library, even though the intepretation of the bits may be different. This was a misconception. The interpretation of the raising and falling signal was so different that the rc-switch library did not see anything.
I thought also, that if I look for raising and falling signals (with attachInterrupt) that I should easily distinguish between "Receiving nothing" and "Receiving signal from remote" like "no activity" versus "some activity". This was also a misconception. "no activity" shows a lot of signals! Noise, I presume.
But then I read that most remotes start with a "long gap" and repeat their signals several times (as along as you push the button). And then I noticed the pattern!
So, no I am able to receive and interpret the signals from my Trust Smart AYCT-102 remote. I will post my solution here.
The signals from my Trust Smart AYCT-102 remote are structured this way:
Important are only the gaps (where the signal is LOW). Their duration differs and contains the information. The pulses (where the signal is HIGH) have always a length of about 260 microseconds, they only separate the gaps and carry no further information
If a gap appears smaller then 130 microseconds, then it was interrupted by noise. Just combine it with the folling pulse (the noise) and the next gap (the rest of the original gap).
The signal starts with a large gap of >10000 microseconds, followed by a small gap of around 2700 microseconds.
Then come the bits: a gap of around 1200 microsencods is a '0', a gap of around 260 microseconds is a '1'.
The signal repeats, which can easily be noticed by the large gap (see number 3).
How often it repeats depends on how long you press the button.
This is it. I designed a state machine approach to interpret this signal. See my sketch in the attachment to this post. When I rum it on my Arduino Uno and press some buttons, I get an output like this on the Serial Monitor:
