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PyMata
PyMata is a high performance, multi-threaded, non-blocking Python client for the Firmata Protocol that supports
the complete StandardFirmata protocol.
A new version for Python 3.5, pymata_aio, can be found here.
The API can be viewed on the wiki.
Major features
- Implements the entire Firmata 2.5.1 protocol.
- Python 2.7+ and Python 3.4+ compatibility through a shared code set. (If you are running Python 3.4 on Linux, please see note below).
- Easy to use and intuitive API. You can view the PyMata API Documentation here or view in the Documentation/html directory.
- Custom support for stepper motors, Sonar Ping Devices (HC-SR04), Piezo devices and Rotary Encoders.
- Requires the use of FirmataPlus for PyMata - installation instructions may be found here.
- Wiring diagrams are provided for all examples in the examples directory.
- Digial and Analog Transient Signal Monitoring Via Data Latches:
- They provide "one-shot" notification when either a digital or analog pin meets a user defined threshold.
- Analog latches compare each data change to a user specified value.
- Comparison operators are <, >, <= and >=
- Digital latches compare a data change to either a high or low, specified by the user.
- Latches can easily be re-armed to detect the next transient data change.
- Latches can be either manually read or a callback can be associated with a latch for immediate notification.
- Optional callbacks provide asynchronous notification of data updates.
Callbacks
Check out the example code on the wiki.
- Digital input pins.
- Analog input pins.
- Encoder changes.
- I2C read data changes.
- SONAR (HC-SR04) distance changes.
- Analog latch condition achieved.
- Digital latch condition achieved.
- Callbacks return data reports in a single list format.
- Polling methods and callbacks are available simultaneously and can be used in a mixed polled/callback environment.
- Callbacks return data in a single list.
The callback data return values
Callback Type |
List Element 0 |
List Element 1 |
List Element 2 |
List Element 3 |
Analog |
ANALOG MODE |
Pin Number |
Data Value |
Not Applicable |
Digital |
DIGITAL MODE |
Pin Number |
Data Value |
Not Applicable |
I2C |
I2C MODE |
I2C Device Address |
Data Value |
Not Applicable |
Sonar |
Trigger Pin |
Distance in Centimeters |
Not Applicable |
Not Applicatble |
Encoder |
Encoder MODE |
Pin Number |
Data Value |
Not Applicable |
Latched Analog |
LATCHED ANALOG MODE |
Pin Number |
Data Value |
Time Stamp |
Latched Digital |
LATCHED DIGITAL MODE |
Pin Number |
Data Value |
Time Stamp |
Control-C Signal Handler
Below is a sample Control-C signal handler that can be added to a PyMata Application.
It suppresses exceptions being reported as a result of the user entering a Control-C to abort the application.
import sys
import signal
# followed by another imports your application requires
# create a PyMata instance
# set the COM port string specifically for your platform
board = PyMata("/dev/ttyACM0")
# signal handler function called when Control-C occurs
def signal_handler(signal, frame):
print('You pressed Ctrl+C!!!!')
if board != None:
board.reset()
sys.exit(0)
# listen for SIGINT
signal.signal(signal.SIGINT, signal_handler)
# Your Application Continues Below This Point
Misc
Special Note For Linux Users Wishing to Use Python 3.5
This project was developed with Pycharm ![logo](https://github.com/MrYsLab/python_banyan/blob/master/images/icon_PyCharm.png)