Program stuck when using Nanpy

[keldos]

I'm trying to interface with an Arduino using Nanpy and the program always gets stuck at this line:

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a = ArduinoApi(connection=connection)

When I press control-C I get the following output:

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Traceback (most recent call last):
  File "nanpy_test.py", line 10, in <module>
    a = ArduinoApi(connection=connection)
  File "build/bdist.linux-armv6l/egg/nanpy/classinfo.py", line 22, in getinstanc
  File "build/bdist.linux-armv6l/egg/nanpy/classinfo.py", line 59, in __init__
  File "build/bdist.linux-armv6l/egg/nanpy/memo.py", line 21, in __call__
  File "build/bdist.linux-armv6l/egg/nanpy/arduinoboard.py", line 55, in wrapper
  File "build/bdist.linux-armv6l/egg/nanpy/arduinoboard.py", line 123, in wrappe
  File "build/bdist.linux-armv6l/egg/nanpy/arduinoboard.py", line 46, in _call
  File "build/bdist.linux-armv6l/egg/nanpy/arduinoboard.py", line 16, in return_
  File "build/bdist.linux-armv6l/egg/nanpy/serialmanager.py", line 92, in readli
  File "build/bdist.linux-armv6l/egg/serial/serialposix.py", line 461, in read
KeyboardInterrupt

Here is the source:

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from nanpy import (ArduinoApi, SerialManager)
from time import sleep

dev = '/dev/ttyACM0'
baud = 9600

print "starting"

connection = SerialManager(device=dev, baudrate=baud)
a = ArduinoApi(connection=connection)
a.pinMode(13, a.OUTPUT)
while True:
        print "on"
        a.digitalWire(13, a.HIGH)
        time.sleep(1)
        print "off"
        a.digitalWire(13, a.LOW)
        time.sleep(1)

The baudrate I have set in the code matches what is set in my cfg.h file. I have also tried it with the default baudrate and the empty SerialManager constructor.

[B.Goode]

How is the Arduino connected to the RPi?

[keldos]

The Arduino is connected to the RPi by USB. When the program is run the 'L' LED will flash a bit and the RX light will blink once very briefly but the program will never display anything after the "starting" print statement.

[B.Goode]

dev = '/dev/ttyACM0'

That looks like the definition of the UART on the GPIO header.

If you are using a usb serial dongle I would expect the virtual serial port to have a name something like /dev/ttyUSB0

So I think your code is failing because it does not get a response from the Arduino.

[keldos]

With that I get the output:

Code: Select all

starting
Traceback (most recent call last):
  File "nanpy_test.py", line 10, in <module>
    a = ArduinoApi(connection=connection)
  File "build/bdist.linux-armv6l/egg/nanpy/classinfo.py", line 22, in getinstance
  File "build/bdist.linux-armv6l/egg/nanpy/classinfo.py", line 59, in __init__
  File "build/bdist.linux-armv6l/egg/nanpy/memo.py", line 21, in __call__
  File "build/bdist.linux-armv6l/egg/nanpy/arduinoboard.py", line 55, in wrapper
  File "build/bdist.linux-armv6l/egg/nanpy/arduinoboard.py", line 123, in wrapper
  File "build/bdist.linux-armv6l/egg/nanpy/arduinoboard.py", line 27, in _call
  File "build/bdist.linux-armv6l/egg/nanpy/arduinoboard.py", line 9, in _write
  File "build/bdist.linux-armv6l/egg/nanpy/serialmanager.py", line 82, in write
  File "build/bdist.linux-armv6l/egg/nanpy/serialmanager.py", line 75, in open
  File "build/bdist.linux-armv6l/egg/serial/serialutil.py", line 282, in __init__
  File "build/bdist.linux-armv6l/egg/serial/serialposix.py", line 289, in open
OSError: [Errno 2] No such file or directory: '/dev/ttyUSB0'

[keldos]

Using connection = SerialManager() I get the same output as I do using dev = '/dev/ttyACM0' and connection = SerialManager(device=dev, baudrate=baud)

[DirkS]

Have you checked that your serial device is present with 'lsusb'.
Have you checked whether /dev/ttyUSB0 and / or /dev/ttyACM0 are present? (just use ls for that).

Gr.
Dirk.

[keldos]

lsusb outputs the following:

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Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
Bus 001 Device 008: ID 2341:0043 Arduino SA Uno R3 (CDC ACM)

[DirkS]

And the ttyxxx ports?

Gr.
Dirk.

[scruss]

That looks like the definition of the UART on the GPIO header.

No, the GPIO UART is /dev/ttyAMA0. ACM0 is one of the standard ones.

It might be a groups/permissions issue. Try these two commands:

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pi@mince ~ $ ls -l /dev/ttyACM0 
crw-rw---T 1 root dialout 166, 0 Dec 31  1969 /dev/ttyACM0
pi@mince ~ $ groups
pi adm dialout …

If groups doesn't return ‘dialout’ in the response, then you likely can't read or write to the device.

Firmata, though elderly and not able to support some fancy devices, is better maintained, and has a userbase who understand and can explain its quirks. Nanpy doesn't have that kind of traction.

cheers,
Stewart

[keldos]

Sorry DirkS forgot that part.

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/dev/tty    /dev/tty19  /dev/tty3   /dev/tty40  /dev/tty51  /dev/tty62
/dev/tty0   /dev/tty2   /dev/tty30  /dev/tty41  /dev/tty52  /dev/tty63
/dev/tty1   /dev/tty20  /dev/tty31  /dev/tty42  /dev/tty53  /dev/tty7
/dev/tty10  /dev/tty21  /dev/tty32  /dev/tty43  /dev/tty54  /dev/tty8
/dev/tty11  /dev/tty22  /dev/tty33  /dev/tty44  /dev/tty55  /dev/tty9
/dev/tty12  /dev/tty23  /dev/tty34  /dev/tty45  /dev/tty56  /dev/ttyACM0
/dev/tty13  /dev/tty24  /dev/tty35  /dev/tty46  /dev/tty57  /dev/ttyAMA0
/dev/tty14  /dev/tty25  /dev/tty36  /dev/tty47  /dev/tty58  /dev/ttyprintk
/dev/tty15  /dev/tty26  /dev/tty37  /dev/tty48  /dev/tty59
/dev/tty16  /dev/tty27  /dev/tty38  /dev/tty49  /dev/tty6
/dev/tty17  /dev/tty28  /dev/tty39  /dev/tty5   /dev/tty60
/dev/tty18  /dev/tty29  /dev/tty4   /dev/tty50  /dev/tty61

and it looks like I have dialout:

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pi@raspberrypi ~ $ ls -l /dev/ttyACM0
crw-rw---T 1 root dialout 166, 0 Nov 11 16:41 /dev/ttyACM0
pi@raspberrypi ~ $ groups
pi adm dialout ...

[B.Goode]

That looks like the definition of the UART on the GPIO header.

No, the GPIO UART is /dev/ttyAMA0. ACM0 is one of the standard ones.

Happy to be factually corrected. Thanks for clarifying.

[keldos]

Thank you all very much for your help. I was able to get it working using Firmata as Stewart suggested.

[B.Goode]

I am pleased this has been resolved for @keldos, using an alternative solution.

For anyone who hits this thread looking for advice on NanPy, there is a previous extensive thread elsewhere on this forum by Tony Goodhew (@tonygo2) which includes a very detailed setup tutorial for NanPy on Raspbian. http://www.raspberrypi.org/forums/viewt ... py#p546921