RPI and 433MHz codes - Wrong code being sent by the send module?

Question

Background I bought some cheapo 433 wireless plug sockets (https://www.lidl.co.uk/en/p/christmas-countdown/silvercrest-wireless-socket-set/p36995) and obviously I can't help but want to control them through the RPI. I had a sender and a reciever module laying around so I went about sniffing the codes. Long story short too much noise, bought a new set which arrived today. I've managed to sniff the codes from the remote which seems to use a repeating set of 4 or 5 codes, always the same protocol and the same pulselength. I have been using this script (https://content.instructables.com/ORIG/F3N/KBEX/J76GIPWM/F3NKBEXJ76GIPWM.py / https://www.instructables.com/RF-433-MHZ-Raspberry-Pi/ - code at the end of the page) to receive the 433 signals.

Using the same tutorial I have used the send script to send my code back to the plug socket to no avail. I plugged the receiver back in and and as you can see from the attached screenshot I transmit one code but receive a handful of different codes on the receiver. I have noticed that I can transmit a code (3625900) on protocol 3 with pulselength of 100 and it is detected as the same code (sometimes a few digits out) but on protocol 5 with a pulselength around 500 +/- 20 or so, could this be a limitation of how quickly the GPIO pins can switch high/low? Or possibly attenuation even over a distance of 1.5in? The plug has activated once out of several dozen repeated attempts.

Where do I go from here? The modules I am using do not currently have additional antennas but they will arrive tomorrow. I doubt that will change the situation as the transmitter is approx 1.5inches from the receiver so I don't see attenuation being the issue. Similarly I have moved the plug socket from 2ft to 2in from the transmitter and again no activity on the plug when I transmit any of the codes aside from one lucky shot. Screenshot below for clarity. EDIT: Added screencap showing codes received when holding down the A On button on the remote while holding the remote right behind the receiver.

Next steps?

Answer 1

I suggest you try using my pigpio library.

It will give far more accurate timings.

Sample Python code

433MHz Keyfob RX/TX

Classes to send and receive 433MHz wireless keyfob codes.
These keyfobs are widely used for remote control of devices.

http://abyz.me.uk/rpi/pigpio/examples.html#Python__433_py

The class contains a test __main__ program (having a test __main__ is quite common for Python classes).

Edit the __main__ part TX and RX values to reflect the Broadcom number GPIO connected to the 433 MHz transmitter and/or receiver. Then to receive just run ./_433.py for receive or ./_433.py code1 code2 ... to send code1, code2, etc. and then receive.

The example instantiates the transmitter with

tx=_433.tx(pi, gpio=TX)

You can add optional parameters

• repeats (default 6)
• bits (default 24)
• gap (default 9000)
• t0 (default 300)
• t1 (default 900)

E.g.

tx=_433.tx(pi, gpio=TX, gap=2285 t0=389 t1=1112)