phySyncFirmata turns your Arduino into a data acquisition card controlled by Python.
Just upload the default firmata sketch into your Arduino and you are all set. Use baud rate 115200 from arduino side also.
phySyncFirmata is an updated version of pyFirmata which adds precise sampling to the API so that it's possible to filter signals and in general do signal processing. Instead of "sleep" commands which have unreliable timing the Arduino performs the sampling in its firmware and transmits the data then to phySyncFirmata. The Python application simply registers a callback which is then called every time after new data has arrived.
Install the Arduino IDE on your computer: https://www.arduino.cc/en/Main/Software
Start the IDE and upload the standard firmata sketch into your Arduino with::
File -> Examples -> Firmata -> Standard Firmata
The preferred way to install is with pip / pip3. Under Linux::
pip3 install phySyncFirmata [--user] [--upgrade]
and under Windows/Mac type::
pip install phySyncFirmata [--user] [--upgrade]
You can also install from source with::
git clone https://github.com/cedt/PhySyncFirmata
cd phySyncFirmata
Under Linux type::
python3 setup.py install
Under Windows / Mac::
python setup.py install
Create an instance of the Arduino class::
from pyfirmata import Arduino
board = Arduino(Arduino.AUTODETECT)
which automatically detects the serial port of the Arduino.
If this fails you can also specify the serial port manually, for example::
board = Arduino('COM4')
Under Linux this is usually /dev/ttyACM0. Under Windows this is a
COM port, for example COM4. On a MAC it's /dev/ttys000, /dev/cu.usbmodem14101 or
check for the latest addition: ls -l -t /dev/*.
In order to sample analogue data you need to specify a sampling interval in ms. The smallest interval is 10ms::
board.samplingOn(samplinginterval in ms)
Calling samplingOn() without its argument sets
the sampling interval to 19ms.
To process data at a given sampling interval register a callback handler and then enable it::
board.analog[0].register_callback(myCallback)
board.analog[0].enable_reporting()
where myCallback(data) is then called every time after data has been received
and is timed by the arduino itself.
You can also read additional analogue pins any time by issuing a read command::
board.analog[1].read()
This is useful for reading additional pins within a callback handler
to process multiple pins simultaneously. Note that the data obtained
by read() is read from an internal buffer which stores the most
recent value received from the Arduino. This call is non-blocking.
You also need to run enable_reporting() on that pin before you can use read().
Digital ports can be written to at any time::
board.digital[13].write(1)
For any other functionality use the pin class below.
The command get_pin requests the class of a pin
by specifying a string, composed of
'a' or 'd' (depending on if you need an analog or digital pin), the pin
number, and the mode ('i' for input, 'o' for output, 'p' for pwm). All
seperated by :. Eg. a:0:i for analog 0 as input or d:3:p for
digital pin 3 as pwm::
analog_0 = board.get_pin('a:0:i')
analog_0.read()
pin3 = board.get_pin('d:3:p')
pin3.write(0.6)
To close the serial port to the Arduino use the exit command::
board.exit()
The directory https://github.com/cedt/PhySyncFirmata/tree/master/examples contains two realtime Oscilloscopes with precise sampling rate, a digital port reader, the ubiquitous flashing LED program and a program which prints data using the callback handler.
Start your program from the (Anaconda-) console / terminal and never within Spyder. Here is an example for Windows::
(base) D:\>
(base) D:\>cd phySyncFirmata\examples
(base) D:\phySyncFirmata\examples>python realtime_two_channel_scope.py
The problem with Spyder is that it won't let your Python program terminate properly which leaves the serial port in an undefined state. If you then re-run your program it won't be able to talk to your Arduino. In the worst case you need to reboot your computer. Bottomline: use Spyder for editing, run the program from the console / terminal.
If you use the --user option to install / update packages Python might keep older versions.
Solution: Do a pip uninstall phySyncFirmata multiple times until no version is left
on your computer. Then install it again as described above.
If you have a new example you think we'd like, please consider sending it to us as a Pull Request.
The original pyFirmata was written by Tino de Bruijn. The realtime sampling / callback has been added by Bernd Porr.