Since the 4408 Blunami only has low current lighting outputs, 2 heavier outputs are needed for 1) Electro-coupler/Proto-coupler and 2) Smoke units.
KarlDL,
Looking forward to the Electro-coupler/Proto-coupler board.
It would be great if that board had the current capacity for Smoke control.
That way two boards can be use to control both higher current loads.
Adding a timer to shutting down the Smoke output saves the wick after fluid tank is empty.
(That timer also reduces battery drain on ‘Dead Rail’ engine/locos.)
As with any design problem there are multiple solutions. This DPDT relay works for coupler. Another identical one works for smoke. The Function output can be set to toggle, ie push on, push off or it can be set to momentary, touch on, release off.
I am using Momentary for the coupler and toggle for the smoke unit. The relay is the only component needed for coupler. For the smoke resistor, again straight track power ~18VAC powers the resistor but that has been increased to 54 ohms, two common 27 ohm smoke resistors in series. Less is possible but thats what was handy.
The other relay pole enables 5v to power the fan motor control circuit.
We have choices, I try to design them as simple as possible while still being reliable.
Pete