Pybytes Downlink Messages

[mcallistertad]

Is there a way to receive messages from pybytes? I don't see anything documented but it would be nice to enable control on the app layer.

Something like:

pybytes.receive_signal(topic, data)

or even have send_signal return the last message posted to the topic when called.

[jirkakrepl]

Hi @mcallistertad,

I agree. Currently, there's no way to do it. We will discuss today and probably implement this functionality.

On Wi-Fi/ LTE Cat m1 we could send any downlink messages over mqtt.

on LoRa/Sigfox we need to do something else - we are constraint by bandwidth and downlink connection windows

[Carl Folkesson]

Hi @jirkakrepl,
Any update on downlink functionality over Wi.Fi/LTE?

[ahmadelmasri]

Hello @Carl-Folkesson,

On the latest Pybytes firmware we have implemented the downlink feature over MQTT.

Steps:

• Once the device is activated
• pybytes.set_config('pybytes_autostart', False)
• in your main.py you have to initialize pybytes
• To send a JSON string via MQTT to the device, you need to use topic d+<device_id>
• The message should start with 0x08h + MESSAGE example: To send {"test":"value"} the hex code is: 087b2274657374223a2276616c7565227d

main.py Test Code:

def callback_function(message):
    print(message)


if (len(pybytes_config['username']) > 4 and len(pybytes_config['device_id']) >= 36 and len(pybytes_config['server']) > 4):
    from _pybytes import Pybytes
    pybytes = Pybytes(pybytes_config, user_callback=callback_function)
    if pybytes.connect_wifi():
        # SEND PING
        pybytes.send_ping_message()

        # SEND DEVICE'S INFORMATION
        # The INFO message should always be sent, otherwise, Pybytes could not be aware
        # of some important information regarding this device, like its firmware version.
        pybytes.send_info_message()

        # ENABLE TERMINAL
        # This should always be enabled if you're using firmware that is compatible with the pybytes terminal.
        # The terminal messages will use the virtual pin (or signal) 255.
        pybytes.enable_terminal()

    else:
        print("Failed to connect to Pybytes! Invalid credentials or network issues?")
else:
    print("Could not load Pybytes configuration!")

NB: Kindly note that this is still experimental.

Let me know if you face any errors.

Have a nice day.

Best Regards,
Ahmad El Masri