Listening to 433 MHz Smoke detectors

Jerry_OR · January 4, 2018, 4:55pm

You are correct, you need to sniff the codes first. I normally use an Arduino plus receiver for this as many of them are non standard and there are several sniffing programs available. I can paste a Python sample program for the transmit side. They are mostly variants on that but you might have to play around a bit. I have roller blinds with 40 & 41 bit codes. Also I have some Lidl sockets which seem to be non standard which took a bit of work to get right.

Jerry_OR · January 4, 2018, 5:00pm

Sample Python program below. This was for some B&Q sockets which were subsequently recalled because of fire hazard issues, so I don’t use it any more. As usual I am indebted to others who posted on this in the past but I don’t remember where / who.

# code from usage of library web site below ------------------------------
#!/usr/bin/env python3

import argparse
import logging
import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)          # disable an execution waring about channel in use

parser = argparse.ArgumentParser()
parser.add_argument("command", help="A1=A-on, A0=A-off, B1=B-on etc. M1=Master on, M0=Master off")
args = parser.parse_args()
command = args.command

from rpi_rf import RFDevice

BIT1_PULSE   = .001000           # microseconds
BIT1_DELAY   = .000330           # sort of averages from a few samples
BIT0_PULSE   = .000420
BIT0_DELAY   = .001020
SYNC_PULSE1  = .000370
SYNC_DELAY1  = .002000
SYNC_PULSE   = .000350
SYNC_DELAY   = .010840

RF_DATA_PIN = 17
bit_value = "0"                   # initialise a character string

GPIO.setup(RF_DATA_PIN, GPIO.OUT)   # GPIO pin set as output

# these are the bit sequences
# signalA1 = '000101010001010101010111'    
# signalA0 = '000101010001010101010100'    
# signalB1 = '000101010100010101010111'
# signalB0 = '000101010100010101010100'
# sequence is A1, A0, B1, B0,  1 = on, 0 = off

signals =  ['000101010001010101010111',
            '000101010001010101010100',
            '000101010100010101010111',
            '000101010100010101010100',]

def sendSync():
  GPIO.output(RF_DATA_PIN, True)
  time.sleep(SYNC_PULSE1)
  GPIO.output(RF_DATA_PIN, False)
  time.sleep(SYNC_DELAY1)

def endSync():
  GPIO.output(RF_DATA_PIN,True)
  time.sleep(SYNC_PULSE)
  GPIO.output(RF_DATA_PIN,False)
  time.sleep(SYNC_DELAY)

def activatePlug(signal):

    for i in range (0,5):            # repeat signal tx at least 4 times - mandatory

#      sendSync()                    # not needed for B&Q sockets

      for k in range (0, 24):
        bit_value = signal[k:k+1]
#        print ("Bit Value = ", bit_value)

        if bit_value == '1':
          GPIO.output(RF_DATA_PIN,True)
          time.sleep(BIT1_PULSE)
          GPIO.output(RF_DATA_PIN,False)
          time.sleep(BIT1_DELAY)

        elif bit_value == '0':
          GPIO.output(RF_DATA_PIN,True)
          time.sleep(BIT0_PULSE)
          GPIO.output(RF_DATA_PIN,False)
          time.sleep(BIT0_DELAY)

#      print ("sending end sync")
      endSync()                       # clean up after each transmission

# main program
# command parameter should be A1, A0, B1, B0
# program will fail if none of the above supplied as a parameter

command_list = ['A1','A0','B1','B0']
signal_index = command_list.index(command)

signal = signals[signal_index]

# print("Switching ", command, "  ", signal)
activatePlug(signal)

# main program ends here

when trying to resolve another issue with RF devices, I had another look at this program and noticed that none of the RPI_RF methods are actually used in the program, so the following line is probably unnecessary:

from rpi_rf import RFDevice

It’s probably just a hangover from an earlier version or different program.

VGE · January 4, 2018, 7:00pm

Awesome! Ill give it a try!

So i got the receiver working last night with the doorbell. The problem is the code, pulselenght and protocol are in no way consistent. Wich one is the one i need?

2018-01-04 18:04:28 - [INFO] rpi-rf_receive: Listening for codes on GPIO 27
2018-01-04 18:04:36 - [INFO] rpi-rf_receive: 10 [pulselength 1032, protocol 4]
2018-01-04 18:04:37 - [INFO] rpi-rf_receive: 4 [pulselength 1336, protocol 2]
2018-01-04 18:04:37 - [INFO] rpi-rf_receive: 512 [pulselength 1504, protocol 4]
2018-01-04 18:05:03 - [INFO] rpi-rf_receive: 2 [pulselength 1921, protocol 2]
2018-01-04 18:05:03 - [INFO] rpi-rf_receive: 1 [pulselength 95, protocol 3]
2018-01-04 18:05:10 - [INFO] rpi-rf_receive: 2 [pulselength 2325, protocol 4]
2018-01-04 18:05:10 - [INFO] rpi-rf_receive: 32 [pulselength 1089, protocol 4]
2018-01-04 18:05:10 - [INFO] rpi-rf_receive: 524288 [pulselength 1152, protocol                                                     4]
2018-01-04 18:05:10 - [INFO] rpi-rf_receive: 256 [pulselength 1271, protocol 4]
2018-01-04 18:05:22 - [INFO] rpi-rf_receive: 256 [pulselength 1215, protocol 5]
2018-01-04 18:05:27 - [INFO] rpi-rf_receive: 8 [pulselength 290, protocol 1]
2018-01-04 18:06:12 - [INFO] rpi-rf_receive: 4 [pulselength 745, protocol 2]
2018-01-04 18:53:24 - [INFO] rpi-rf_receive: 33 [pulselength 268, protocol 1]
2018-01-04 18:53:24 - [INFO] rpi-rf_receive: 32 [pulselength 1298, protocol 4]
2018-01-04 18:53:24 - [INFO] rpi-rf_receive: 65 [pulselength 1355, protocol 4]
2018-01-04 18:55:39 - [INFO] rpi-rf_receive: 2 [pulselength 1276, protocol 5]
2018-01-04 18:55:39 - [INFO] rpi-rf_receive: 4 [pulselength 2030, protocol 4]
2018-01-04 18:55:50 - [INFO] rpi-rf_receive: 1 [pulselength 1826, protocol 4]
2018-01-04 18:55:50 - [INFO] rpi-rf_receive: 16 [pulselength 1164, protocol 4]
2018-01-04 18:55:50 - [INFO] rpi-rf_receive: 8 [pulselength 878, protocol 2]
2018-01-04 18:55:58 - [INFO] rpi-rf_receive: 1 [pulselength 930, protocol 4]
2018-01-04 18:55:59 - [INFO] rpi-rf_receive: 8 [pulselength 817, protocol 5]
2018-01-04 18:56:52 - [INFO] rpi-rf_receive: 26 [pulselength 223, protocol 3]
2018-01-04 18:56:52 - [INFO] rpi-rf_receive: 1 [pulselength 101, protocol 3]
2018-01-04 18:56:52 - [INFO] rpi-rf_receive: 1 [pulselength 1206, protocol 4]
2018-01-04 18:56:52 - [INFO] rpi-rf_receive: 2 [pulselength 497, protocol 1]

VGE · January 4, 2018, 8:00pm

Found the problem. It was on 3.3v and not 5v. Now ill try again

VGE · January 6, 2018, 8:03pm

@robmarkcole about the redo of your project, are you using : Raspberry Pi RF Switch component?

robmarkcole · January 6, 2018, 8:57pm

I’m just receiving RF, no particular need to ring my own doorbell…

VGE · January 6, 2018, 9:08pm

How are you receiving? What component are you using?

robmarkcole · January 6, 2018, 9:21pm

ricricucit · April 1, 2018, 3:08pm

what was on 3.3v and not 5v? Can you please elaborate? (I’m experience a similar problem)

VGE · April 1, 2018, 8:28pm

Hi,

The GPIO pins on the Pi!

phipe · March 4, 2019, 7:24pm

@VGE, did you ever manage to get the signal from the Renkforce smoke alarms and into HA?

VGE · March 4, 2019, 9:18pm

Hi, i never bought them because i couldn’t get it to work. I do have an other way of listing: sonoff RF bridge, which i have used to listen to rf successfully.

Planning to order them when i have some spare time to test.