Pymata4 is a Firmata client that, like its asyncio sibling, pymata-express, allows you to control an Arduino using the high-performance FirmataExpress sketch. It uses a conventional Python API for those that do not need or wish to use the asyncio programming paradigm of pymata-express.
A User's Guide is available, containing an annotated API as well as links to working examples.
It supports both an enhanced version of StandardaFirmata 2.5.8, called FirmataExpress, as well as StandardFirmata.
- FirmataExpress adds support for:
- HC-SR04 Ultrasonic Distance Sensors using a single pin.
- Stepper Motors.
- Piezo Tone Generation.
- Baud rate of 115200
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Fully documented intuitive API
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Python 3.7+ compatible.
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Set the pin mode and go!
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Data change events may be associated with a callback function, or each pin can be polled for its last event change.
- Each data change event is time-stamped and logged.
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User's Guide, Including Examples.
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Implements 100% of the StandardFirmata Protocol (StandardFirmata 2.5.8).
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Advanced auto-detection of Arduino devices (when using FirmataExpress).
Here is an example that monitors data changes on a digital input pin. It demonstrates both callback and polling techniques
import time
import sys
from pymata4 import pymata4
"""
Setup a pin for digital input and monitor its changes
Both polling and callback are being used in this example.
"""
# Setup a pin for analog input and monitor its changes
DIGITAL_PIN = 12 # arduino pin number
POLL_TIME = 5 # number of seconds between polls
# Callback data indices
# Callback data indices
CB_PIN_MODE = 0
CB_PIN = 1
CB_VALUE = 2
CB_TIME = 3
def the_callback(data):
"""
A callback function to report data changes.
This will print the pin number, its reported value and
the date and time when the change occurred
:param data: [pin, current reported value, pin_mode, timestamp]
"""
date = time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(data[CB_TIME]))
print(f'Pin: {data[CB_PIN]} Value: {data[CB_VALUE]} Time Stamp: {date}')
def digital_in(my_board, pin):
"""
This function establishes the pin as a
digital input. Any changes on this pin will
be reported through the call back function.
:param my_board: a pymata_express instance
:param pin: Arduino pin number
"""
# set the pin mode
my_board.set_pin_mode_digital_input(pin, callback=the_callback)
while True:
try:
# Do a read of the last value reported every 5 seconds and print it
# digital_read returns A tuple of last value change and the time that it occurred
value, time_stamp = my_board.digital_read(pin)
date = time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(time_stamp))
# value
print(f'Polling - last value: {value} received on {date} ')
time.sleep(POLL_TIME)
except KeyboardInterrupt:
board.shutdown()
sys.exit(0)
board = pymata4.Pymata4()
try:
digital_in(board, DIGITAL_PIN)
except KeyboardInterrupt:
board.shutdown()
sys.exit(0)And here is the console output:
pymata4: Version 1.00
Copyright (c) 2020 Alan Yorinks All Rights Reserved.
Opening all potential serial ports...
/dev/ttyACM0
Waiting 4 seconds(arduino_wait) for Arduino devices to reset...
Searching for an Arduino configured with an arduino_instance = 1
Arduino compatible device found and connected to /dev/ttyACM0
Retrieving Arduino Firmware ID...
Arduino Firmware ID: 2.5 FirmataExpress.ino
Retrieving analog map...
Auto-discovery complete. Found 20 Digital Pins and 6 Analog Pins
Polling - last change: 0 change received on 1969-12-31 19:00:00
Pin: 12 Value: 0 Time Stamp: 2020-03-07 08:52:10
Pin: 12 Value: 1 Time Stamp: 2020-03-07 08:52:12
Polling - last value: 1 received on 2020-03-07 08:52:12 This project was developed with Pycharm 