Found a neat little circuit board recently that has a lot of uses around the layout. The device is a VELLEMAN Multi-Function Relay Switch model K8015, available from Amazon and others. At just $27.95 it has 14 different programmable functions, including timers, switching, flashing, interval, random switching, etc. It has two pre-programmed delays and a learning mode for delays of 2s up to 12 days. EEPROM for delay time storage so it can be powered down without loss of memory. Operates from 9-12 VAC or DC, max load for relay contacts is 5 amps. This is a KIT, however, and you must have the skill, tools (and eyesight!) to work on small PC boards. I had to troubleshoot mine after all the soldering was done for about 20 minutes to correct a couple of bad solder joints. To do that it is helpful to understand logic levels and open collector circuits.
Here is how I use mine, utilizing its two delays: I used it to time stops for my Lionel #60 trolley. The trolley runs on a shuttle track with stops at each end. The last piece of track at each end is center rail insulated from the rest of the track, and has a #260 bumper mounted on it. With those end tracks unpowered, the trolley coasts to a stop, but not before it lightly bumps the 260 bumper activating the reverse function. On a schedule of once per minute, power is applied via this board's relay to the "end" tracks to power the trolley to start moving. The power is applied for only about 3 seconds, just long enough to get it off the end track and onto the continuously powered section. At the other end the same thing happens. Speed of the trolley needs to be set such that it's stopping at the bumper is smooth, while still activating the reverse. Unfortunately, the trolley does not remain lit during the stop.
Here are the timer modes that can be set by the on-board DIP switches: momentary, toggle, start/stop timer, staircase timer, due-time staircase timer, non-retriggerable timer, turn-on delay, timer with early trigger prevention, turn off delay interval timer, blinking circuit, blinking circuit with timer, random timer, trigger at release timer, interruptible real time staircase timer, and learning mode. I anticipate buying a few more of these for other uses on the layout. Manual is here:
https://www.esr.co.uk/manuals/k8015.pdf
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