Make controle script.

[Pascal]

I have several units build from scratch to work in my home domotica.
All my units work with the I²C pins (SDA/SCL)
You can check if a device is present on the bus by using the i2cdetect program from the i2ctools package- i2cdetect 0 -y(raspberry pi R1) or i2cdetect 1 -y (raspberry pi R2).

Now my question is if it is possible to make a python code that first checks if there are units connected on the I²C pins and if so show it on screen.

Thx.

[cae2100]

you could try something like this, just a bunch of try/except statements:

Code: Select all

locations=['locations that you'd scan for addresses', 'end']
bus = smbus.SMBus(1)
for device in locations:
	try:
		(commands to try location on the i2c bus.)
		break
	except:
		try:
                        another try statement stuff to try to search the i2c bus
                except:
                        try:
                              and on and on....
                if device == 'end':
			print "Nothing found, Please check cable connections."
			exit()

[Pascal]

I don't realy understand your code.
Maybe you have a working example?

[cae2100]

no working example, I was just giving a concept. you have a list of all addresses used by the i2c, and what the code does is search through them using a for loop to loop through all of the combinations, and if it finds one, you can assign a varable to 1 or something like that to tell that the location is being used, then after all locations have been checked, it'd print out whatever locations it shows something at.

[Pascal]

In your code

Code: Select all

locations=['locations that you'd scan for addresses', 'end']

The word 'end' do you mean the last address or just the word 'end' ?

[cae2100]

just the word end, I use it as kinda a stopper for my projects. here's an example of what I mean, this is for auto searching and connecting to a serial port so it works on any system.

Code: Select all

import serial
locations=['/dev/ttyACM0', '/dev/ttyACM1','/dev/ttyACM2', '/dev/ttyACM3','/dev/ttyACM4', '/dev/ttyACM5','/dev/ttyUSB0','/dev/ttyUSB1','/dev/ttyUSB2','/dev/ttyUSB3', '/dev/ttyUSB4', '/dev/ttyUSB5', '/dev/ttyUSB6', '/dev/ttyUSB7', '/dev/ttyUSB8', '/dev/ttyUSB9', '/dev/ttyUSB10', 'com2', 'com3', 'com4', 'com5', 'com6', 'com7', 'com8', 'com9', 'com10', 'com11', 'com12', 'com13', 'com14', 'com15', 'com16', 'com17', 'com18', 'com19', 'com20', 'com21', 'com1', 'end']

for device in locations:
	try:
		#print "Trying...",device
		serialport = serial.Serial(device, 2400, timeout = 0)
		break
	except:
		#print "Failed to connect on",device
		if device == 'end':
			print "Unable to find Serial Port, Please plug in cable or check cable connections."
			exit()

[-rst-]

Hmm, as long as it works... But might be better to code without the 'end' string - something along this:

Code: Select all

import serial
locations=['/dev/ttyACM0', '/dev/ttyACM1','/dev/ttyACM2', '/dev/ttyACM3','/dev/ttyACM4', '/dev/ttyACM5','/dev/ttyUSB0','/dev/ttyUSB1','/dev/ttyUSB2','/dev/ttyUSB3', '/dev/ttyUSB4', '/dev/ttyUSB5', '/dev/ttyUSB6', '/dev/ttyUSB7', '/dev/ttyUSB8', '/dev/ttyUSB9', '/dev/ttyUSB10', 'com2', 'com3', 'com4', 'com5', 'com6', 'com7', 'com8', 'com9', 'com10', 'com11', 'com12', 'com13', 'com14', 'com15', 'com16', 'com17', 'com18', 'com19', 'com20', 'com21', 'com1']

deviceFound = False
for device in locations:
   try:
      #print "Trying...",device
      serialport = serial.Serial(device, 2400, timeout = 0)
      deviceFound = True
      break
   except:
      #print "Failed to connect on",device

if not deviceFound:
    print "Unable to find Serial Port, Please plug in cable or check cable connections."
    exit()

...just to avoid doing the call serial.Serial('end', ...)