tm1637-clock

About

A simple clock daemon that works with a character device created by the tm1637-kmod kernel driver or the tm1637-cuse service. It is a successor of my other project digitalclock based on a library tm1637-display. Brightness control can be done through the sysctl variables of the kernel driver "tm1637.ko" or by sending control strings to the character display device.

The daemon:

• creates a pidfile and uses daemon(8) if run with -b parameter for detach from a terminal;
• uses timer_create(2) for output time and marking seconds by colon (1, 2 times per second or always on);
• uses a signal interception for stopping itself correctly;
• interacts with device /dev/tm1637 by writing digits to it and using ioctl calls;

I wrote this program for my little-task server on Raspberry Pi 2 (Another task is a NTPD service for getting a time from GLONASS).

Dependencies

For the tm1637-clock program You need:

• ARM SoC, e.g. Raspberry Pi 2 or 3 (Orange or Banana also is good);
• FreeBSD 12 operating system;
• C compatible compilator (FreeBSD already has a native clang);
• An installed and loaded the tm1637-kmod kernel driver.

Download

git clone https://gitlab.com/alexandermishin13/tm1637-clock.git

Installation

As desribed above, You need firstly to install and load the tm1637 kernel module. For a description of how to do this, refer to the tm1637-kmod project page

For the program installation type:

make
sudo make install

The executable file will be installed as /usr/local/sbin/tm1637clock and the service file as /usr/local/etc/rc.d/tm1637clock. You also can a copy a /rc.conf.d/tm1637clock.example to /usr/local/etc/rc.conf.d/tm1637clock to control the service.

For deinstallation type:

sudo make uninstall

Usage

The program can be run either as a daemon (with -b parameter) and as a standalone program. A clock point change mode can be set by a -p key followed by integer. Possible values are 0-always on, 1-blinks once a second and 2-blinks twice per second. Least processor efficient mode is 2, although it was optimized. Almost two times more efficient mode is 1 as it less often writes to the display. And even more efficient mode is 0 as it writes to the display just once a minute.

Typical it is run as a daemon by a service startup script:

./tm1637clock -b [-p <mode>]

but You can run it like a regular program by omitting the -b option.

You can turn on, off or set brightness of the display by interacting with the tm1637 kernel driver using sysctl variables. No special privileges required for it:

sysctl dev.tm1637.0.brightness=3
sysctl dev.tm1637.0.on=0

Manage the service

If You wish to start service automatically with a boot of operating system, You can:

• add to a file /etc/rc.conf
• create a new file /usr/local/etc/rc.conf.d/tm1637clock and add a followed string to it (Or just copy its example from sources):

tm1637clock_enable="YES"
tm1637clock_flags="-b -p 2"

Then You can manage the service by one of a command:

service tm1637clock start
service tm1637clock stop
service tm1637clock status