Python PyBluez loses Bluetooth connection after a while
- by Travis G.
I am using Python to write a simple serial Bluetooth script that sends information about my computer stats periodically. The receiving device is a Sparkfun BlueSmirf Silver.
The problem is that, after the script runs for a few minutes, it stops sending packets to the receiver and fails with the error:
(11, 'Resource temporarily unavailable')
Noticing that this inevitably happens, I added some code to automatically try to reopen the connection. However, then I get:
Could not connect: (16, 'Device or resource busy')
Am I doing something wrong with the connection? Do I need to occasionally reopen the socket? I'm not sure how to recover from this type of error.
I understand that sometimes the port will be busy and a write operation is deferred to avoid blocking other processes, but I wouldn't expect the connection to fail so regularly. Any thoughts?
Here is the script:
import psutil
import serial
import string
import time
import bluetooth
sampleTime = 1
numSamples = 5
lastTemp = 0
TEMP_CHAR = 't'
USAGE_CHAR = 'u'
SENSOR_NAME = 'TC0D'
#gauges = serial.Serial()
#gauges.port = '/dev/rfcomm0'
#gauges.baudrate = 9600
#gauges.parity = 'N'
#gauges.writeTimeout = 0
#gauges.open()
filename = '/sys/bus/platform/devices/applesmc.768/temp2_input'
def parseSensorsOutputLinux(output):
return int(round(float(output) / 1000))
def connect():
while(True):
try:
gaugeSocket = bluetooth.BluetoothSocket(bluetooth.RFCOMM)
gaugeSocket.connect(('00:06:66:42:22:96', 1))
break;
except bluetooth.btcommon.BluetoothError as error:
print "Could not connect: ", error, "; Retrying in 5s..."
time.sleep(5)
return gaugeSocket;
gaugeSocket = connect()
while(1):
usage = psutil.cpu_percent(interval=sampleTime)
sensorFile = open(filename)
temp = parseSensorsOutputLinux(sensorFile.read())
try:
#gauges.write(USAGE_CHAR)
gaugeSocket.send(USAGE_CHAR)
#gauges.write(chr(int(usage))) #write the first byte
gaugeSocket.send(chr(int(usage)))
#print("Wrote usage: " + str(int(usage)))
#gauges.write(TEMP_CHAR)
gaugeSocket.send(TEMP_CHAR)
#gauges.write(chr(temp))
gaugeSocket.send(chr(temp))
#print("Wrote temp: " + str(temp))
except bluetooth.btcommon.BluetoothError as error:
print "Caught BluetoothError: ", error
time.sleep(5)
gaugeSocket = connect()
pass
gaugeSocket.close()
EDIT: I should add that this code connects fine after I power-cycle the receiver and start the script. However, it fails after the first exception until I restart the receiver.
P.S. This is related to my recent question, Why is /dev/rfcomm0 giving PySerial problems?, but that was more about PySerial specifically with rfcomm0. Here I am asking about general rfcomm etiquette.
