This mostly applies to folks with the old GE Low-Voltage systems (or Touchplate, Sierra, Pyramid, some Remcon, and so on), but anyone could use this sort of thing to control light fixtures or other low-current loads (avoid inductive loads unless you add a snubber or the like).
In this video, I'm using a 24 VAC doorbell transformer which is a little smaller than the Low-Voltage transformers normally used in the old systems, but it's a sufficient stand-in.
I will cover installation and wiring of the i4 and many other devices in detail in another video. It's not very hard at all and Shelly's provided instructions are very thorough.
The RIBL24B relay is a little over $60. I said around $30 in the video because I swear I saw that price somewhere. Here's a link to the one I bought (affiliate link):
amzn.to/3zh0Dji
If for some reason you want the doorbell transformer, you can get it here (again, affiliate link):
amzn.to/3AUysay
The incredible Shelly i4 DC (not an affiliate link and not currently available on Amazon):
www.shelly.com/en-us/products/shop/shelly-plus-i4-dc
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