This is a python program to turn your seven segment
Generation I Delcom Engineering USB Numeric Display (USB ID 0fc5:1227)
into a clock.

Author: Stuart Pook, http://www.pook.it/, 2011-2019

Find the names of the displays on your machine (these names can be
directly passed to delcom-clock):

    ls /sys/bus/usb/drivers/usbsevseg | grep :

You can turn the clock on and off by writing 1 or 0 into a named pipe
(see the --control option).

http://www.delcomproducts.com/
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/usb/misc/usbsevseg.c

I would like delcom-clock to exit as soon as the device is unplugged. I
don't know how to do this. I only seem to be able to find out that the
device has been removed when I write to it. Polling on the device does
not seem to give me a wakeup when the device is removed. This is why
delcom-clock continues to write to the device even when the clock is off.

Delcom-clock should use raw mode so that it can show space characters
rather than hyphens.

I have not tested this with a six digit 7 segment display because I
don't have one. If the kernel module only accepts 6 digits, then delcom-clock
with just use the last 6 digits of the text to be displayed.

If you have 8 digit display and Linux 2.6.37 or earlier you need to
recompile the usbsevseg module if you want to use more than just
the rightmost 6 digits. Just set MAXLEN to 8 rather than 6. See the
README.module script for how to do this.

This program can be found at http://github.com/stuart12/delcom-clock

Thanks to Harrison Metzger for the kernel driver for this device.