Here’s a nice little power supply:

It’s one of many LED drivers currently available on the market.

These supplies are designed to provide a fixed current – not voltage. What this means is that if you “overload” them, then they will regulate the voltage down to the point where the current reaches a preset value (700 mA in this case).

In itself, this isn’t really useful for powering anything but power LEDs, but this unit also specifies that as long as the load remains under 650 mA, it will supply a fixed voltage of about 6V. So the other way to interpret these specs, is to see this as a 6V power supply with automatic current limiting to 700 mA.

This means that if we add the optional diode to a JeeNode v5 or v6, then the voltage would be just right to power one or more 5V relays.

The nice thing about these units is that they are fully “potted”, i.e. encased with proper high-voltage isolation.

This might offer a practical way to set up mains-powered JeeNodes, with perhaps a Relay Plug to switch simple AC loads, or a triac for switching / dimming incandescent lights. Another option would be to use a MOSFET to switch 1..3W power LEDs.

PS. Unfortunately, I don’t remember where I got this particular unit (yeah, I know – I feel pretty stupid!)