Decoding 433MHz Remote

Using Arduino Networking, Protocols, and Devices
1

I have been trying to decode a 433MHz remote using the RC-Switch library. I have been able to receive and generate a wave, however I am having difficulty creating a protocol/decoding the wave. To make sure all my hardware works, I successfully decoded wall plug in that has a remote that simply turns the plug in on or off.

I have attached an image of what the wave generated looks like. The thing that is really puzzling me is the two abnormally sized waves on the far left. Any help whats going on here or how to decode the remote/create protocol, would be great.! Pool remote decoded|690x137

2

The remote may not use the RC-Switch protocol.

Here is a tutorial that describes a general method to decode remotes and other 433 MHz devices.
https://rayshobby.net/wordpress/reverse-engineer-wireless-temperature-humidity-rain-sensors-part-1/

3

His process makes sense, unfortunately I need to essentially replicate the wave from, which he doesn't exactly touch on. I am looking to get rid of the remote and control using arduino w transmitter. It is starting to seem RC-Switch may not be useful for my remote.

4

The Audacity trace allows you to deduce the signal timing, and to reproduce it.

From the Audacity trace, you can certainly determine whether the remote uses the basic RC-Switch protocol, or not. Keep in mind that there are many RC-Switch protocol variants. They differ in the bit and sync pulse timing.

Once you have determined the timing, you can add that protocol to the RC-Switch library code.

If it is not RC-Switch, you have to write your own encoder.

5

Right, I have gotten the timing both from a scope and from the add_new_remote in the wiki of rc-switch. The issue I'm having with designing the protocol is that there isn't 2 specific patterns, ie. (1 pulse lengths low, 2 pulse lengths high for a 0 and 2 pulse lengths low, 1 pulse lengths high for a 1). I found a different remote that took me about 10 minutes to decode and control with the arduino and transmitter, so I can confirm my hardware is working.

6

That's NRZ format (non-return to zero)

7

Any recommendations on decoding/replicating wave form? I'm not super familiar with NRZ.

8

It is just on/off keying, but you have to decode the signal somehow, unless you intend to replicate the entire transmission burst.

Which you forgot to show us. Please post images inline, or attach them as described in the "How to get the best out of this forum" post.

9

Pool remote decoded
Pool remote decoded3781×752 148 KB

Sorry about that, hope this is visible.

10

Wave forms are the same using a scope with an RF sniffer.

11

Can you not see a pattern there? Keep in mind, the receiver may convey some edges a little inaccurately... that would give you bits, but the protocol is probably proprietary, so good luck with that.

12

Yes, but that is not ALL of the burst. You need to see the entire transmitted packet to see the potential preamble, start/stop signals, etc.

13

That is the extent of what I receive. It repeats with a delay. I cropped the delay on both sides.

14

Unfortunately I do not see a pattern. My reasoning for posting.

15

Not even, that most of the pulses are the same duration, or almost exactly double that?

Also can you please post an entire pattern? Your crop should include some dead space before and after so the whole thing is more discernable.

When you are not receiving a signal, you should see random noise. That is the only way to recognize the actual beginning and end of transmission.

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