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 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. Log on as root, and say:
> 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:
> ubos-admin createsite --ask App to run: rasptimer Hostname (or * for any): * 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 ... 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@example.com): firstname.lastname@example.org
Step 3. There is no step three :-) 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? You often can find me on #ubos.