Need a timer circuit

Time delay relay. Do a search on Google, eBay or Amazon and you’ll get several ideas. I’m sure some other forum members will weigh in with specific suggestions. 

You might want to post this question on the Electrical Forum. 

I recently purchased 4 time delay relays from eBay, $20 total and arrived much earlier than advertised

Jon1443 posted:

I recently purchased 4 time delay relays from eBay, $20 total and arrived much earlier than advertised

Do you have the link to the auction on ebay?

Yes, many choices on eBay, Amazon, elsewhere.

Direct links to eBay are supposedly not allowed on OGR per terms-of-use but you can easily find many sellers of the above module for about $3 with free-shipping from Asia.  

Most of these low cost modules operate on, say, 12V DC voltage.  And have a relay which can switch 5 or more Amps of AC current so more than suitable to control one or more O-gauge accessories.

For what you stated, you want a module that is "triggerable" since you press a momentary button to start the action.  That is, you apply a momentary voltage via the pushbutton to start the action (30 seconds of power in your case).  I even set this module to 30 seconds to illustrate.  This particular module even lets you define what the pushbutton does.  For example, when pressing the button you can:

1) start a single 30 second interval (pressing button again while active does nothing)

2) start-or-restart the 30 second interval (pressing the button again while active extends another 30 seconds)

3) reset the interval (pressing button while active stops the 30 second interval).

There are more sophisticated timer modules for a few dollar more.  For example triggering the module can turn on the relay for 30 seconds (or whatever you program), then turn off for 5 seconds (or whatever you program), then repeat this ON-OFF cycle 7 times (or whatever you program).  All in response to a single button press!

You get the 12V DC to operate these module from a 12V DC wall-wart adapter - about $2-3 on eBay free shipping from Asia. 

Or you can get an AC-to-DC converter module which will generate 12V DC from train transformer Accessory Voltage (14-16V AC or even 18V AC command track voltage) also for about $2-3 on eBay free shipping.  One 12V DC adapter or AC-to-DC regulator module can power a dozen or more timer modules.

Any low-cost momentary pushbutton switch can function as the trigger.   If using the above timer, the wiring would look like this for 3 accessories.  The current flowing in the 12V DC wiring on the left is modest (well less than 1 Amp) so less expensive thinner wiring can be used - 24 AWG for example.  There is probably existing Accessory Bus wiring around the layout.  Some accessories can use for than 1 Amp so use suitably sized wiring - I'd think 18 AWG would be sufficient for most applications. 

If you want to "over-ride" the timer module and have a toggle switch that simply turns on the accessory all the time, place the toggle switch across the 2 relay screw-terminals (labeled NO and Com) on the right side of the timer module.

And the way these modules are triggered, you can use a 5-cent diode with a pushbutton so that you can have individual buttons triggering one timer module/accessory...while having an "ALL" pushbutton that triggers all timer modules at once.  

I think I'll stop now.

Hello all I am working on a train track that is in a hospital and we somehow fried the timer control for the train. Now I am on the hunt for a new timer. I have attached some photos of the old timer and wanted to know if the timer suggestion on this page would work in place of this old timer?

You can also pick up computer ATX power supply breakout boards to give you an almost unlimited supply of DC voltage.  I have a basement full of used computer power supplies so it was a no brainer for me.

https://www.amazon.com/CHENBO-...619192181&sr=8-4

John

I think you might even be able to install it with the existing wiring.

It appears you have:

- 12V DC power from the left 2 red wires?

- 2 white wires on the left from a momentary 2-terminal push-button switch?

Most digital timer modules of this ilk have a relay capable of 10 Amps of switching.  So if the existing standalone relay itself fails at some point, you can re-wire to use the timer module's relay.  I suspect the existing timer module's relays were not up to the current requirements.

This module does require a one-time programming exercise to set the time delay to however many seconds or minutes in response to the pushbutton.  It can be exasperating as the instructions are no doubt translations. Definitely not as simple as turning the knob on the existing module to set the time interval!

As indicated earlier, I get these from eBay-Asia for less than $5 shipped...but it does take a few weeks.  I see the same or at least very similar modules on Amazon with U.S. shipping for around $10 each.

If I understand your application, there are many timer modules that will do the job.  If you go with the particular timer shown I am quite familiar with its operation.