An on-again, off-again model train?
October 4, 2010 7:48 PM   Subscribe

Is there a simple way to put an electrical outlet on a "two minutes on, five minutes off" duty cycle?

My wife is working on an art installation that includes a model train. We'd like to have the train run for two minutes or so and then rest for five minutes. This would make the moving train more of an "event" in the context of the installation.

I thought it would be easy to find an AC outlet timer that lets me program a simple duty cycle like this, but it's not. They all run on 24-hour cycles, and they rarely go down to gradations finer than 15 minutes. The digital ones have a limited number of on/off events, so even if I wanted to code in each of the on/off events by hand, I couldn't do it.

A friend found a fog machine timer that would allow an "on" time of up to 30 seconds and "off" time of up to 2 minutes. That's close, and we might end up going with that. Anyone have any better ideas?
posted by TPIRman to Technology (7 answers total) 1 user marked this as a favorite
 
Are you handy with electronics, or know anyone who is? This is totally doable with something like an Arduino-controlled power outlet.
posted by DMan at 8:08 PM on October 4, 2010


Smarthome.com sells X 10, and other, controllers that perhaps do this.
posted by llc at 8:10 PM on October 4, 2010


Best answer: Microcontrollers are overkill for this application. You are looking for a cyclical timer, like this one.
posted by drdanger at 9:13 PM on October 4, 2010 [1 favorite]


I'd cobble together a two stage time with a pair of 555s and hook that up to a relay.

Depending on the setup, it might be easier to have to relay between the track and the transformer, thereby saving you the trouble of having to screw with line current and voltages. You could also cobble together a little regulated power supply and run the whole shooting match off the output of the transformer, thereby avoiding the need for batteries.
posted by Kid Charlemagne at 9:30 PM on October 4, 2010


I use a specific type of relay for this type of thing. Cruzet makes a bunch of really flexible units.

Here's one with an octal socket you can get at Digikey for $75.0_Catlink&name=646-1193-ND

It's setup to be a repeat cycle timer and you can dial in on/off times with two separate knobs. Very simple wiring. You'll need a socket for it. Digikey is your friend.

memail with specific questions if you need to.
posted by FauxScot at 4:13 AM on October 5, 2010


Fixed link

Fauxscot be needing to preview.
posted by FauxScot at 4:17 AM on October 5, 2010


Response by poster: Thanks, all, for your replies! I really appreciate your taking the time to help me out. I ended up going with drdanger's suggestion, just because it seemed like the most straightforward thing for me to put together on our tight timeframe.
posted by TPIRman at 10:41 AM on October 5, 2010


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