Remote Firmata Management

The methods in this section allow your application to perform some Firmata management functions remotely.

keep_alive

For Arduino's utilizing an ATmega328P processor, this exclusive FirmataExpress feature will reset the Arduino if serial communication is lost between pymata-express and the Arduino.

 async def keep_alive(self, period=1, margin=0.3)

    This is a FirmataExpress feature.

    Periodically send a keep alive message to the Arduino.

    If the Arduino does not received a keep alive, the Arduino will physically reset itself.

    Frequency of keep alive transmission is calculated as follows: 
        keep_alive_sent = period - margin

    :param period: Time period between keepalives.
                   Range is 0-10 seconds. 
                0 disables the keepalive mechanism.

    :param margin: Safety margin to assure keepalives are 
                   sent before period expires. Range is 0.1 to 0.9

Example:

keep_alive.py

Notes:

When keep_alive is called, it spawns and runs in its own thread.

send_reset

 async def send_reset(self)

    Send a Sysex reset command to the arduino

Examples:

All examples call shutdown, which in turn calls send_reset.

Notes:

This command will reset several Firmata internal data structures.

It resets its internal i2c flags to indicate there are no i2c devices present.
Digital reporting is turned off.
It resets any analog pin that was set to a digital mode back to analog mode.
If a pin was configured for tone, the tone is turned off.
It clears all servo entries from its servo map.
It sets the number of active sonar devices to zero.

The shutdown method calls send_reset.

shutdown

  async def shutdown(self)

    This method attempts an orderly shutdown. 
    If any exceptions are thrown, they are ignored.

Examples:

All the examples call shutdown.