Hi @Gordon and @AllObjects - thank you.
With your advice - I'm pretty sure I would be able to do this build with a DC relay module using the (less-preferred - due to I already have 24VAC solenoids) latching DC solenoid valves.
Can you please share some more details about the TRIAC approach, and, how I can achieve the same objective (wireless control of solenoids)?
I wonder how you would recommend that I get 24V AC to the solenoids? Maybe http://www.powerstream.com/inv-12dc-24vac.htm?
What would be the best way to keep the price low if I wanted a single puck.js to control a single solenoid (either 5VDC or 24VAC)?
Maybe there is a less-feature-rich version of puck.js which would have only one or two outputs (for powering the relay)?
Maybe I could use 24VAC to power the puck.js?
Maybe something be integrated onto puck.js so that it could also supply 24V AC (providing a sufficient battery is used) - thereby reducing the number of moving parts.
@Gordon - Is there a version of puck.js which I could purchase now that would satisfy my solenoid needs? The Esprunio is a bit more feature-rich than I need.