Use a Raspberry Pi as a schedulable timer for GPIO hardware, configurable over the web. Uses WiringPi. While I use it on the original Raspberry Pi, I can't think of a reason it shouldn't work on Raspberry Pi 2, 3, 4 or Zero.
This is the software for the pool timer project described at http://upon2020.com/blog/2012/12/my-raspberry-pi-pool-timer-why/
Rasptimer should run on any Linux-based OS that runs on the Raspberry Pi, but you will have to manually put all the files in the right place, setup your web server, install packages, including creating the configuration file from the template.
If you run UBOS, it's much simpler.
''Step 1.'' Write UBOS to an SD Card suitable for your Raspberry Pi, as described here.
''Step 2.'' Enable the hl-experimental repository on UBOS. To do so,
as root, uncomment the
two lines in /etc/pacman.d/repositories.d/hl-experimental, and then
run sudo ubos-admin update.
''Step 3.'' Run:
> sudo ubos-admin createsite --ask
Then answer the questions. Each pin that you give a name will show up in the web interface; unnamed pins are skipped. Here is an example transcript:
> sudo ubos-admin createsite --ask
Hostname (or * for any): *
Site admin user id (e.g. admin): admin
Site admin user name (e.g. John Doe): Administrator
Site admin user password (e.g. s3cr3t):
Site admin user e-mail (e.g. [email protected]): [email protected]
...
App to run: rasptimer
App rasptimer suggests context path /rasptimer
Enter context path:
Any accessories for rasptimer? Enter list:
App rasptimer suports a value for title: My pool on-line (duh!)
App rasptimer suports a value for pin1: Main pump
App rasptimer suports a value for pin2: Auxiliary pump
The previous command will have downloaded all the code, and the libraries, created the right Apache config files, and so forth, and even restarted your web server. Rasptimer is ready to use.
Questions? Post to the UBOS forum.