Shelly 1 as 12V Remote Relay

A Shelly 1 is an inexpensive smart home relay, which can be configured to run and control 12V DC instead of 230V AC. It can also be flashed with Tasmota, for local integration with something like Home Assistant, or left using the stock firmware for use with its own cloud-based app.

A picture being worth a thousand words:

And now for some words:

The input side is on the right. The Wagos are 221. Solid core cable is recommended for the Shelly terminals- ferrules might not be thin enough. The relay contacts are dry, which is why the positive DC is brought to the I terminal.

Critical: since the Shelly is shipped configured for 230V AC supply, the jumper MUST be moved to the position nearest the terminals, else it will not function / will blow up. Note also the polarity: DC positive is mains neutral, counter-intuitively. Do NOT hook this up to mains in this configuration.