Develop Reference

How to send an API frame to a remote XBee using Digi XBee Python module?

I am moving code from Python XBee library to Digi's Python XBee library and I am unable to locate syntax in the docs on how to send a API frame to a remote XBee. I am using S1 and S1 Pro devices where the "local" device is attached to a Beaglebone and the "remote" devices are standalone out in the wild.
I have the basic framework down:
from digi.xbee.devices import XBeeDevice, RemoteXBeeDevice, XBee64BitAddress
PORT = '/dev/ttyO1'
BAUD = 9600
API_FRAME = 'long-hex-string-here'
local_xbee = XBeeDevice(PORT, BAUD)
local_xbee.open()
# Instantiate a remote XBee device object.
remote_xbee = RemoteXBeeDevice(local_xbee, XBee64BitAddress.from_hex_string("0013A20040DD7DCD"))
# Transmit frame to remote_xbee - unsure of correct method and syntax
# perhaps XBeePacket.create_packet(hex string here)
# local_xbee.send_data(remote_xbee, "api frame here?") ??
local_xbee.close()
but I am unable to locate syntax for how to transmit my constructed API frame. Based upon the Introduction section in the docs I presume that is the correct approach. I am not interested in broadcasting to all devices on the network but rather unicast communication.

I have some older model of the source when I could get it to work.
…
I have some WiFi Xbee modules that I used w/ some converter boards (base boards). I used it to attach the communication of the Xbee from one computer to another, e.g. random desktop to BeagleBone Black via USB instead of UART. So, I would use the source, listed below, to attach my USB dongle for the Xbee communication from the BBB to the other field module.
Their I/O stuff can be found here: https://github.com/digidotcom/xbee-python/tree/master/examples/io.
Also...changing just some of their lines in their source w/ the USB dongle WiFi adapter boards proved valuable in signaling LEDs and other sensors.
Oh and you will need what they are now calling Carrier Boards. It is the adapter board I just typed out. So, if you have already got a Carrier Board, use lsusb as the command in Linux to find your USB "name."
So, for instance, if lsusb brings up /dev/ttyUSB0, then that is the port identification.
And you can use that section, from lsusb, to then change your xbee modules in the xtcu software from Digi.
…
from digi.xbee.devices import XBeeDevice
from digi.xbee.io import IOLine, IOMode
import time
import threading
# TODO: Replace with the serial port where your local module is connected to.
PORT = "/dev/ttyUSB0"
# TODO: Replace with the baud rate of your local module.
BAUD_RATE = 9600
REMOTE_NODE_ID = "Xbee_B"
IOLINE_IN = IOLine.DIO2_AD2
IOLINE_OUT = IOLine.DIO4_AD4
def main():
print(" +-----------------------------------------------+")
print(" | XBee Python Library Get/Set Remote DIO Sample |")
print(" +-----------------------------------------------+\n")
stop = False
th = None
local_device = XBeeDevice(PORT, BAUD_RATE)
try:
local_device.open()
print("local device: ", local_device.get_node_id())
# Obtain the remote XBee device from the XBee network.
xbee_network = local_device.get_network()
remote_device = xbee_network.discover_device(REMOTE_NODE_ID)
if local_device is None:
print("Could not find the remote device")
exit(2)
def io_detection_callback():
while not stop:
# Read the digital value from the input line.
io_value = remote_device.get_dio_value(IOLINE_IN)
print("%s: %s" % (IOLINE_IN, io_value))
# Set the previous value to the local output line.
local_device.set_dio_value(IOLINE_OUT, io_value)
time.sleep(2)
th = threading.Thread(target=io_detection_callback)
remote_device.set_io_configuration(IOLINE_IN, IOMode.DIGITAL_IN)
local_device.set_io_configuration(IOLINE_OUT, IOMode.DIGITAL_OUT_HIGH)
time.sleep(1)
th.start()
input()
finally:
stop = True
if th is not None and th.is_alive():
th.join()
if local_device is not None and local_device.is_open():
local_device.close()
if __name__ == '__main__':
main()
So, see the PORT = "/dev/ttyUSB0" section of the source?
This is where I attached my Xbee module to the Carrier Board and then attached the Carrier Board to the BBB by way of USB.
Um, this may not answer a question but give more insight as to how to handle Digi Devices/Modules.
I also think that if you want to venture in this direction of UART communication w/ Xbee and the BeagleBone Black, it may be more complicated. I will keep searching my text.
P.S. This book goes over some methods to connect, Experiment 10 and Experiment 16, your "BBB" to a UART, Xbee, and how to communicate. It is a bit too in depth to get all of the communication ideas from this book but this is it:
The Hands-on XBEE Lab Manual, Experiments that Teach you XBEE Wireless Communications – Jonathan A Titus

Controlling RGB-Matrix via SPI (Python)

The Raspberry Pi has a Broadcom BCM 2835 chip allowing it to interface with SPI devices on its GPIO pins. I encountered a problem adressing LEDs in a 8x8 Matrix via SPI.
I want to adress single LEDs on the matrix, but I haven't figured out, which bytes adresses which LED(s).
SPIdev seems to be the right library for this purpose und I stumbled upon this snippet of code:
import spidev
import time
spi = spidev.SpiDev()
spi.open(0, 0)
spi.max_speed_hz = 7629
# Split an integer input into a two byte array to send via SPI
def write_pot(input):
msb = input >> 8
lsb = input & 0xFF
spi.xfer([msb, lsb])
# Repeatedly switch a MCP4151 digital pot off then on
while True:
write_pot(0x1FF)
time.sleep(0.5)
write_pot(0x00)
time.sleep(0.5)
Does anyone know which values adresses (a) specific LED(s)?
In C/C++ adressing works very well via the wiringpi-library, a useful documentation can be found here:
http://wiki.52pi.com/index.php/RPI-RGB-LED-Matrix_SKU:EP-0075

Can't get Kodi to accept keys emitted from python-uinput?

I'm emitting keys from a python script using python-uinput. Basic stuff such as up / down / enter / esc.
As far as I can see this works fine on my desktop, in the terminal, and with the browser. But when I run Kodi, it doesn't seem to respond at all. Is this something to do with it being a fullscreen application?
NB: I'm running Raspbian on model 3 Raspberry Pi.

Maybe you need to do: sudo modprobe uinput
The following script works for me to send Function key 12 to vice (a C64 emulator) based on a button press on a GPIO:
import uinput
import RPi.GPIO as GPIO
import time
GPIO.setmode(GPIO.BCM)
GPIO.setup(21, GPIO.IN, pull_up_down=GPIO.PUD_UP)
wasPressed=False
# set up keystroke input
device = uinput.Device([uinput.KEY_F12])
while True:
button_inactive = GPIO.input(21)
if not button_inactive and not wasPressed:
device.emit_click(uinput.KEY_F12)
print "sending F12"
wasPressed=True
if button_inactive:
wasPressed=False
time.sleep(0.1)
Note that I used uinput.KEY_F12 twice. The script should be run as root.

How to use Arduino Uno analog pins as digital pins with pyfirmata

I am trying to use Arduino analog pins (A0-A5) as digital pins (D14-D19) with pyfirmata. I'm doing a simple blink test with D14 (or A0) to test this:
#!/usr/bin/python
# Blink test with analog as digital pins
# Import required libraries
from pyfirmata import Arduino, util
from pyfirmata import INPUT, OUTPUT, PWM
from time import sleep
# Associate port and board with pyFirmata
port = '/dev/cu.usbmodem1451'
board = Arduino(port)
# Pause to sync
sleep(1)
led = board.get_pin('d:14:o')
time = 1
while True:
led.write(1)
print ("On")
sleep(time)
led.write(0)
print ("Off")
sleep(time)
To enable analog pins to act as digital pins, I've gone into pyfirmata's boards.py file (as show in the github repo at https://github.com/tino/pyFirmata/blob/master/pyfirmata/boards.py) and changed line #3 from
digital': tuple(x for x in range(14)),
to
digital': tuple(x for x in range(20)),
I don't get an error when I run my python script, but the LED doesn't blink (don't worry, I'm positive the LED was in the right way).
Does anyone know how I can effectively instantiate digital pin 14 as an output pin with pyfirmata (as in the line led = board.get_pin('d:14:o'))
By the way (not that I think this affects anything) but I'm running Mac OSX with Yosemite.
Thank you!

The standard firmata that we use in Arduino, makes all analog pins input by default. So instead of changing anything in boards.py file, go to standard firmata file in arduino ide and find this ...
switch (mode) {
case PIN_MODE_ANALOG:
if (IS_PIN_ANALOG(pin)) {
if (IS_PIN_DIGITAL(pin)8) {
pinMode(PIN_TO_DIGITAL(pin), INPUT);
Now comment the pinMode line so that the firmata does not make any analog pin input
Now go to void setup() function and explicitly define nature of analog pins as shown below.
Firmata.begin(57600);
while (!Serial) {
}
pinMode(14,OUTPUT);
pinMode(15,INPUT);
pinMode(16,INPUT);
pinMode(17,INPUT);
pinMode(18,INPUT);
pinMode(19,INPUT);
digitalWrite(14,LOW);

Raspberry Pi python serial FT232 not receive 8bytes

I FT232 module connected to the Raspberry Pi (with USB cable). I want to receive 8bytes (1 byte). On Windows, Terminal draws me correctly beats (eg. 00001011). In the following python script:
#!/usr/bin/python
import serial
import binascii
ser = serial.Serial('/dev/ttyUSB0', 115200, timeout=1)
while True:
str1 = ser.read(1)
if str1 == '':
print ''
else:
print bin(int(binascii.hexlify(str1),16))
returns only 2 bits at the end:
0b11111100 ,
0b11111101 ,
0b11111110 ,
0b11111111
What am I doing wrong that draws me just 2bits at the end?
Below please find screen how to receive data on Windows:
http://mateok.ovh/windows.jpg
And on Raspberry Pi:
http://mateok.ovh/linux.jpg
I would like to get on the Raspberry Pi received data were the same.
Edit:
I was able to find a solution! It turned out that the reason is ... that the device had been connected before starting the Raspberry Pi! If they Disconnect and reconnect only when the Raspberry Pi starts - values are returned well! Maybe someone knows the cause of this? And how can I fix it? I do not want every time you re-connect the converter ..