I’m trying to roll my own here. I have an Asus WL520GU running openwrt and python. Basically I’m learning about the Tweetawatt and various sensors. All using xBee series 1 radios.
My python script basically loops through the 4 active xbees. Now I’d like to add a new xbee that I can send a signal to via the python script, for example, to turn on a light.
IOW, the reciever in the asus is, well, receiving. How do I change it to occasionally transmit?
See some sample code below…
Any leads and tips appreciated. TIA,
Chris.
from xbee import xbee
ser = serial.Serial(SERIALPORT, BAUDRATE)
ser.open()
while True:
packet = xbee.find_packet(ser)
xb = xbee(packet)
print xb
# after calling a web service, I'd like to transmit a signal to an xbee that is connected to a relay/light.
The xbee.py lib:
# By Amit Snyderman
# $Id: xbee.py,v 1.1 2009/01/20 18:23:01 cvs Exp $
import array
class xbee(object):
START_IOPACKET = '0x7e'
SERIES1_IOPACKET = '0x83'
def find_packet(serial):
if hex(ord(serial.read())) == xbee.START_IOPACKET:
lengthMSB = ord(serial.read())
lengthLSB = ord(serial.read())
length = (lengthLSB + (lengthMSB << 8)) + 1
return serial.read(length)
else:
return None
find_packet = staticmethod(find_packet)
def __init__(self, arg):
self.digital_samples = []
self.analog_samples = []
self.init_with_packet(arg)
def init_with_packet(self, p):
p = [ord(c) for c in p]
#print p
#print len(p)
self.app_id = hex(p[0])
if self.app_id == xbee.SERIES1_IOPACKET:
addrMSB = p[1]
addrLSB = p[2]
self.address_16 = (addrMSB << 8) + addrLSB
self.rssi = p[3]
self.address_broadcast = ((p[4] >> 1) & 0x01) == 1
self.pan_broadcast = ((p[4] >> 2) & 0x01) == 1
self.total_samples = p[5]
self.channel_indicator_high = p[6]
self.channel_indicator_low = p[7]
local_checksum = int(self.app_id, 16) + addrMSB + addrLSB + self.rssi + p[4] + self.total_samples + self.channel_indicator_high + self.channel_indicator_low
for n in range(self.total_samples):
dataD = [-1] * 9
digital_channels = self.channel_indicator_low
digital = 0
for i in range(len(dataD)):
if (digital_channels & 1) == 1:
dataD[i] = 0
digital = 1
digital_channels = digital_channels >> 1
if (self.channel_indicator_high & 1) == 1:
dataD[8] = 0
digital = 1
if digital:
digMSB = p[8]
digLSB = p[9]
local_checksum += digMSB + digLSB
dig = (digMSB << 8) + digLSB
for i in range(len(dataD)):
if dataD[i] == 0:
dataD[i] = dig & 1
dig = dig >> 1
self.digital_samples.append(dataD)
analog_count = None
dataADC = [-1] * 6
analog_channels = self.channel_indicator_high >> 1
validanalog = 0
for i in range(len(dataADC)):
if ((analog_channels>>i) & 1) == 1:
validanalog += 1
for i in range(len(dataADC)):
if (analog_channels & 1) == 1:
analogchan = 0
for j in range(i):
if ((self.channel_indicator_high >> (j+1)) & 1) == 1:
analogchan += 1
dataADCMSB = p[8 + validanalog * n * 2 + analogchan*2]
dataADCLSB = p[8 + validanalog * n * 2 + analogchan*2 + 1]
local_checksum += dataADCMSB + dataADCLSB
dataADC[i] = ((dataADCMSB << 8) + dataADCLSB)# / 64
#print "sample #"+str(n)+" for chan "+str(analogchan)+" = ["+str(dataADCMSB)+", "+str(dataADCLSB)+"] = "+str(dataADC[i])
analog_count = i
analog_channels = analog_channels >> 1
self.analog_samples.append(dataADC)
#print dataADC
#checksum = p[10 + analog_count * n]
#local_checksum = 0xff - local_checksum;
# if (checksum - local_checksum != 0):
# print "Checksum error! checksum: %s, local_checksum: %s" % (checksum, local_checksum)
def __str__(self):
return "" % (self.app_id, self.address_16, self.rssi, self.address_broadcast, self.pan_broadcast, self.total_samples, self.digital_samples, self.analog_samples)
And if you are too stressed out by this Xbee advanture, take a look at