Control radio-controlled power sockets with any Arduino-compatible board and a cheap 433Mhz emitter.

1. Some 5V-enabled board with one digital I/O pin and serial communication (eg. USB). I've tested this code successfully with:
   • A $2 “Blue Pill” STM32F103C8T6 from Aliexpress (bluepill_f103c8_128k)
   • A $6 AT MEGA 2560 clone from Aliexpress (megaatmega2560)
2. A 433 Mhz RF transmitter module. I often see them referred to as “Superheterodyne”. They are often sold in receiver/transmitter kits, for instance this $1 one from Aliexpress.
3. Radio-controlled (433.95MHz) power sockets. This was tested with two RSL366R , sold under the Chacon brand, part number SKU 54660.

You'll possibly need more stuff to upload the program to your device. I used a TTL-232R-3v3 to flash my Blue Pill. Arduino boards like the 2560 are programmed using the built-in USB port and do not need extra cables.

Plug the 433 Mhz transmitter 5V and GND pins to 5V and GND on your board, and its data pin to any appropriate digital pin on the board. Refer to your board pinout to choose an appropriate digital I/O pin and make note of its Arduino pin number. The example below uses Arduino pin number 10.

Refer to the Platformio documentation on how to compile and program your device from this code. You might need to tweak platformio.ini to fit your environment, such as serial port names or other boards.

You do not need to change the C++ code for normal usage. All the relevant communication parameters (data pin, pulse length, pulse repeats) are dynamically configurable at runtime. See below.

Once flashed, the device should appear as a serial interface (eg. /dev/ttyACM0) to your host computer. It speaks a very simple binary protocol for configuring and sending commands. Please refer to the self-explanatory Python code below.

Well-known pulse codes for RSL366R are documented here.

You might want to tweak the pulse length and TX repeats if the values used below are flaky on your setup. 5 TX repeats and a 413 µs pulse length work very reliably for me.

import serial, struct

# Serial speed is 9600 bauds.
# Assuming little-endian platform.
s = serial.Serial("/dev/ttyACM0", 9600)

# First, let's configure the device.
# Size (bytes) | 1            | 1            | 1            | 2
# Index        | 0            | 1            | 2            | 3, 4
# Meaning      | cmd          | transmit pin | pulse repeat | pulse length
CONFIGURE = 0x00
s.write(struct.pack("<BBBH", CONFIGURE, 10, 5, 413))
# Device confirms with an ASCII-encoded LF-terminated line.
print(s.readline())
# b'transmitPin=10;repeatTx=5;pulseLength=413;\n'

# Then let's send a pulse code.
# Size (bytes) | 1            | 4
# Index        | 0            | 1
# Meaning      | cmd          | transmit code
SEND = 0x01
s.write(struct.pack("<BL", SEND, 1381717))
# Device confirms with an ASCII-encoded LF-terminated line.
print(s.readline())
# b'codeToSend=1381717;\n'

GNU General Public License v3.0 or later.