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gotthardp / python-mercuryapi

Python wrapper for the ThingMagic Mercury API
MIT License
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Access readers via mac adress #74

Closed rasidmusic closed 5 years ago

rasidmusic commented 5 years ago

Hey guys - hope you can help me out. I am trying to use two readers at the same time. I have usually assigned a reader with reader = mercury.Reader("tmr:///dev/ttyUSB0")

With a second reader: readerA = mercury.Reader("tmr:///dev/ttyUSB0") readerB = mercury.Reader("tmr:///dev/ttyUSB1")

The problem: The ttyUSBx keep swapping around after a restart of the system. I need an exact way to use a defined reader. Is there a way of doing that via the mac address (which is unique of course)? Something like readerA = mercury.Reader("23:df:34:ds:xy") readerB = mercury.Reader("54:96:gt:le:43")

Thank you

gotthardp commented 5 years ago

I assume you are on Linux. Did you try defining udev rules to fix the device name? https://rolfblijleven.blogspot.com/2015/02/howto-persistent-device-names-on.html

If it's an IPv6 capable network (LAN) reader (and you access it via LAN/Ethernet) you may be able to access it via auto-generated local address, with is based on the device MAC.

rasidmusic commented 5 years ago

Thanks for the link. I tried to find an unique identifier to determine the exact reader - but could not find any. idProduct and idVendor are the same (CH-340 both) and I can't find any attribute that is unique and persistent. Any ideas?

gotthardp commented 5 years ago

If there is no serial number? The article says there could be one (but not necessarily).

rasidmusic commented 5 years ago

Apparently there is no serial number... EDIT: Well there is SerialNumber=0 but that does not help very much

gotthardp commented 5 years ago

Too bad. You will need to invent some trick.

One idea: There is a serial number in the MercuryAPI, so (if that works) you could initialize both readers and distinguish which is which afterwards using that number. Another idea: Connect one using another method than the other (e.g. USB and LAN).

rasidmusic commented 5 years ago

Note: I am using the Sparkfun RFID UHF Reader (based on the m6e nano) and a CH340 to connect it to the RasPi. Apparently the CH340 does not have any storage to store any type of unique id, like serial number (https://arduino.stackexchange.com/questions/6617/setting-serial-number-on-ch340-usb-serial-device). So I need an FTDI

gotthardp commented 5 years ago

The serial number I was talking about is stored inside the m6e nano. I added a new function get_serial that will (hopefully) print an unique string for each of the readers. Please check.