This has meant I am able to add bits to the alarm system much more simply than using my custom boards - anywhere. As I reported before the Shelly Plus 1 is great as it can work on DC or AC, but this modules is specifically for DC usage.
The Shelly Plus i4DC, which is like the Shelly Plus i4 (which is AC), is powered from 5V to 24V DC. This is great news as it can work from 12V and 24V alarm systems, and the typical 13.8V of a battery box quite safely. You could even wire to a USB 5V supply.
It has 4 inputs which connect to GND, and this works well for connecting to fire alarms, door sensors, and so on, and can easily have spares for tamper and dummy wires. I would struggle to make something like this for the same cost, and when I factor in my time this is a total no brainer.
I have also worked out the GPIO:-
- GPIO0: Output for small LED (hard to see through case).
- GPIO12: Input for SW1 signal (external switch) but needs configuring as pull down.
- GPIO14: Input for SW2 signal (external switch) but needs configuring as pull down.
- GPIO27: Input for SW3 signal (external switch) but needs configuring as pull down.
- GPIO26: Input for SW4 signal (external switch) but needs configuring as pull down.
- GPIO25: Input for small yellow button on the case, but needs configuring as pull up.
There are also 6 external connection pins for programming which are common to most Shelly, and not mains live on this model:
- GPIO3 RX to shelly
- GPIO1 TX from shelly