MrYsLab
commented
9 years ago The cause of the problem was determined. Leonardo boards, unlike Uno boards continue sending update data after the serial port is closed. PyMata now sends a Firmata Reset command to the Arduino so silence it before closing the port. To handle the case of a user pressing control-c before the application finishes processing, a signal handler should be added to the application. PyMata handles the case where control-c is pressed before pyamata.init completes.
All examples will be updated to include this signal handler.
The signal handler that optionally can be added to applications to gracefully handle control-c is:
board = None
# create a PyMata instance
board = PyMata("/dev/ttyACM0")
def signal_handler(signal, frame):
print('You pressed Ctrl+C!!!!')
if board != None:
board.reset()
sys.exit(0)
signal.signal(signal.SIGINT, signal_handler)
On occasion the exceptions shown below are encountered when rerunning an application. It appears to occur mostly on Leonardo boards. Work around until a fix is provided is to remove the USB cable from the Arduino and then plug it back in.
File "C:\Python27\Lib\threading.py", line 783, in bootstrap self.bootstrap_inner() File "C:\Python27\Lib\threading.py", line 810, in __bootstrap_inner self.run() File "C:\Python27\Lib\site-packages\PyMata\pymata_command_handler.py", line 822, in run method(command_data) File "C:\Python27\Lib\site-packages\PyMata\pymata_command_handler.py", line 486, in digital_message prev_data = self.digital_response_table[pin][self.RESPONSE_TABLE_PIN_DATA_VALUE]
IndexError: list index out of range