Appropriate device for switching low current AC

[greenscum1]

Hello I am designing an irrigation controller. I have found this wonderful tutorial however I am left with a few questions:
https://www.instructables.com/id/Raspbe ... on-System/

Is the relay really necessary for this circuit, or would it be possible to reduce the parts count by using something like a triac, SCR or optocoupler?
I have seen devices like this, which seem like they could be switched by the 5V from the RasPi without needing an additional MOSFET or other transistor: https://eu.mouser.com/ProductDetail/Lit ... J8025LH4TP

This is the datasheet for the water valves I am trying to switch:
https://stc.dripdepot.com/files/8413/84 ... 20SPEC.pdf

Any help is GREATLY appreciated, Thank you!

[Burngate]

SCR? no - it's unidirectional.

Triac? The problem as I see it is that one leg has to be common to both the Pi and the valve power supplies.
I'd prefer to keep them separate if possible,

Optocoupler? none that I know about could handle AC at the current you want.
A solid-state relay could have one built-in, but is likely to be wanting 5v drive, so you're back to where you were.

An old-fashioned mechanical relay driven by a FET does exactly what you want - when it's off, it's infinite resistance; when it's on, it's close to zero.
It may be old-fashioned and clunky, but it's reliable.

[gordon77]

This optocoupler appears to do 2.2A AC, 10A peak, upto 60V

LCA715S

https://www.digchip.com/datasheets/part ... 5S-pdf.php

I've never used one.

[drgeoff]

viewtopic.php?f=37&t=261683#p1594299

[Burngate]

https://www.digchip.com/datasheets/part ... 5S-pdf.php

Technically, it's a solid-state relay, not just an optocoupler. Hair-splitting is my forte.

viewtopic.php?f=37&t=261683#p1594299

It may be old-fashioned and clunky, but it's reliable.

Probably my age

[hippy]

Is the relay really necessary for this circuit, or would it be possible to reduce the parts count by using something like a triac, SCR or optocoupler?

I can't foresee replacing a relay and its switching transistor/FET with anything else resulting in fewer components.