The weather is getting so cold currently that the cars heater needs to be turned on for more than an hour. Since I don’t want to wake up any earlier than possible, I went to get a socket that could be remotely timed. I found Belking Wemo switch, but unfortunately it proved to be an utter waste of money. The configuration software is extremely poor and the device refused to connect to my homes access point no matter what I tried.
I had previously bought cheap sockets with a remote. These were branded “Opal” and cost next to nothing in a pack of two sockets and one remote and they seem to work well enough. Only minus was the strange 12v battery the remote uses.
I popped open the remote to check how it worked. The layout seems to be easy enough. The +12v from the battery is dropped to +5v for the microcontrolled under the epoxy blob. The controller scans the keypad and generates the code which is fed to RF part. The RF transmitter requires the +12v straight from the battery and operates in 433 MHz frequency. I cut the signal trace from the controller to the transmitter and soldered wires to the test pad in the signal trace and the ground. Using the oscilloscope I checked what the controller is outputting when the keys are pressed.