I've just connected several waterproof DS18B20 sensors to my Raspberry Pi B+ V1.2 running Jessie Lite.

I get the list of sensors attached by

ls /sys/bus/w1/devices

and I can see all the devices. I notice that if I add a further device, it appears in the /sys/bus/w1/devices directory within maybe 2 seconds of being attached.

However, if I detach a device, it can take 60 seconds before it disappears from the directory. Is it possible for me to force this directory to refresh more rapidly?

  • First, why is this an issue? You really shouldn't be making connections to a running Pi. Commented Mar 30, 2016 at 23:17
  • I have several sensors to add (three, initially, maybe four) to add to several Pis (6 or maybe 8). As you may know, they are serialised. I don't fancy fitting one, rebooting, for each sensor in order to establish its serial number. Connecting them to the Pi which it's running will do no more harm than closing a switch connected to a GPIO port would do. I imagine that's why the kernel module continues to search for new devices after it has been added.
    – KDM
    Commented Apr 1, 2016 at 17:18


Browse other questions tagged or ask your own question.