radio-pi

The library enables RaspberryPi to integrate with radio-controlled devices (ie. power sockets). The library was inspired by the tutorial:

https://www.instructables.com/Super-Simple-Raspberry-Pi-433MHz-Home-Automation/

The library consists of two parts:

• signal_receiver.py is used with radio receiver unit to decode signal emitted by remote control,
• signal_sender.py is used for sending previously decoded signal with the usage of radio transmitter unit connected to Pi.

Dependencies

The library has two main dependencies:

• RPi.GPIO to control the GPIO on a Raspberry Pi
• matplotlib to create signal plots To install them use the file requirements.txt

Reading a signal

Create an instance of the SignalReceiver class passing two arguments:

• collecting_signal_period to specify how long the sample should be collected.
• file_name file to which the signal is stored in json format.

To start calling signal use method collect_signal passing 2 arguments:

• mode which reflects numbering of the IO pins: GPIO.BCM or GPIO.BOARD
• receiver_pin to which radio receiver is connected.

Optionally you can use method plot_signal to see signal plot.

Signal properties (its value and duration) are written to a json file.

Example

signal_object = SignalReceiver(timedelta(seconds=5), "radio_signal.json")
signal_object.collect_signals(mode=GPIO.BCM, receiver_pin=22)
signal_object.plot_signal()

Output file example

Signal is stored in a json file using the following format:

{
  "signals": [1, 0, 1, 0, 1, 0, 1, 0, 1, 0],
  "durations": [0.0001679, 0.0047470, 0.0001689, 0.0004420, 
    0.0004740, 0.0001309, 0.0004750, 0.0001330, 0.0001519, 0.0004610]
}

Sending a signal

Create an instance of the SignalSender class passing a single attribute:

• signal_file - file name with previously written signal by SignalReceiver.

Call method run_transmitter providing 2 attributes:

• mode which reflects numbering of the IO pins: GPIO.BCM or GPIO.BOARD
• sender_pin to which radio sender is connected.

Example

radio_waves = SignalSender("radio_signal.json")
radio_waves.run_transmitter(mode=GPIO.BCM, sender_pin=23)

Examples of correct signal plots

Plots representing two signal pulses:

Repetitive signal blocks indicate the correctness of encoded signals:

Zooming in, the length of the zeros and ones becomes visible:

Examples of incorrect signal plots

Plot representing a single signal pulse:

Zooming in, non-repetitive tendency of signal blocks is visible: