I bought this set of three sockets and a remote - http://www.clasohlson.com/uk/Remote-Control-Switch-3-pack/18-2035 and a cheap set of a 433Mhz transmitter and receiver from eBay. The manual refers to the sockets as EMW200R.
I came across this link which was trying to achieve the same thing and suggested attaching the receiver to the sound card on a PC and recording the signal sent by the remote control using audio software such as Audacity to identity pulses being sent and their length. Originally my recordings seemed to show audio waves instead of on/off pulses until further reading mentioned that the receiver must be connected to a line in socket instead of a microphone input. After making this change I could clearly see the pattern of hi/low pulses and measure their length.
This similar link mentions that commands are made up of the socket group, socket number, command and sync. Each of these is made up of a series of high and low pulses. I found that my sockets used the same series of pulses for each of these with the exception of a different sync command and the pulse lengths being slightly different.
I put together some python code to control the sockets by passing command line arguments of the pin number (1 - 26), the socket group (A - D), the socket number (1 - 4) and the command (On or Off). Because it is using the GPIO port, the code needs to be run as root (using sudo).
To get the code to run using RASPBMC I needed to install the following:
sudo apt-get install python-devsudo apt-get install python-pipsudo pip install rpi.gpio
The code is as follows:
I then wanted to set up a cron job to turn a lamp on at 5PM every day and off at 11PM. To do this I needed to enable cron in the RASPBMC settings (not required for other distributions) and then edit the root cron table using:
sudo crontab -e -u rootI added the following lines to turn a socket on daily at 5PM and off at 11PM:
0 17 * * * /usr/bin/python /home/pi/EMW200R.py 11 A 1 On0 23 * * * /usr/bin/python /home/pi/EMW200R.py 11 A 1 Off
Hey,
ReplyDeleteI'm very interested in this as I'd like to do the same thing using just the standard RPi.GPIO library. Every other tutorial seems to want you to install 3 different libraries and run a bunch of pre-fab code which I'd like to avoid when it should just be as simple as your code here!
Have you had any luck with using this to control 433mhz sockets? Does the time.sleep() seem to work for constructing such fine sequences?
Thanks a lot, glad I came across this :)