Triggers For Multi Relay Arduino Boards; Cleaned Up!!

There are occasional inquiries about how to turn on an Accessory for, say, 30 seconds in response to a momentary push-button.  This might be a show or open-house where an accessory-rich layout would be too "busy" if dozens of accessories are simultaneously flashing, spinning, whirring, etc.  There's also the audience participation benefit especially with kids getting to control the action!  There are of course time-delay relay modules but they can be spendy. 

With the delay board under discussion, all you need is a momentary push-button (door bell) switch installed in place of an insulated-rail section!  Now when a kid presses the button, it fires the corresponding relay for some settable interval with 10 Amp power handling capability.

@stan2004 posted:

There are occasional inquiries about how to turn on an Accessory for, say, 30 seconds in response to a momentary push-button.  This might be a show or open-house where an accessory-rich layout would be too "busy" if dozens of accessories are simultaneously flashing, spinning, whirring, etc.  There's also the audience participation benefit especially with kids getting to control the action!  There are of course time-delay relay modules but they can be spendy.

With the delay board under discussion, all you need is a momentary push-button (door bell) switch installed in place of an insulated-rail section!  Now when a kid presses the button, it fires the corresponding relay for some settable interval with 10 Amp power handling capability.

Neat idea Stan. Limited only by our imagination I guess. You could also add a PB switch wired in parallel to any track operated channel, so as to manually operate the accessory/device whenever desired.

Rod

OK it seems we are about done with development of this project, so it's about time to go to press and publish the gerbers and a description of how it works. These are attached below for anyone who wishes to order and build either of these boards.

Please note there are two separate gerber files. One is the more complex delay board file, and the other is the simpler anti-chatter board file. Normally I would have ordered boards first and tested them out to make sure they work. But in this case the circuit design is pretty simple and I bread-boarded both cases to arrive at the suggested component values. User beware however! (a cleverly disguised disclaimer)! The description document is in pdf format and covers both board designs. There is no BOM file because they are pretty simple. Component values can easily be pulled off the circuit diagrams in the pdf document. If anyone needs hand with any details I will be happy to help.

I should point out that both these boards are intended to be used to trigger any of the readily available offshore multi-relay arduino-type boards, that are triggered typically by grounded (or Hi/Lo) input signals, and typically use either 5V or 12V DC 10 amp relays. Insulated outside rail triggering is assumed, but other trigger methods can be used just as well.

Thanks are due to all those who contributed, and especially Stan2004 for his original circuit designs and very helpful suggestions and hookup sketches. I am merely the collector of information and board designer for this project, haha.

Rod

Not to flog a dead horse, but I came up with a variant of the previous boards, designed to convert a positive trigger signal to a negative signal, that would allow use of the Low only multi-relay boards. It also has anti-chatter capability built in, so it can be used with an isolated rail trigger, old-school 153 trigger, reed switch, or other mechanical device. Here's the circuit:

I need to breadboard this guy yet just to make sure it works, and to fine tune the component values. I am also thinking of an on board jumper to take R5-C1 buffer out of the circuit, if anti-chatter is not needed. It would be a solder-it-in-and-forget type jumper.

Can anyone see any issues with this, or any reason it wouldn't work?

Rod

Well the new circuit above works just fine. Component values as shown are good and a C1 of 4,7uF gives about 1/2 to 1 second buffer, or delay. 22uF increases the delay to about 4 seconds, and 47uF to about 7 seconds. So this board provides pos to neg trigger inverting, anti-chatter, and fixed delay by changing C1, all in one.

If anti-chatter or delay is not needed for some reason, you only need omit R5 and C1, and jumper the pads for R5. Very straightforward. The pos trigger signal will still invert to neg just fine.

Here is the board layout:

Rod

So I went ahead and ordered 10 boards for each of the trigger variations, and they arrived today by Fedex after only 8 days! Very fast. I built up one of each of the boards and tested them out; all work just as expected. Pictures below. Note that I only populated 1 or 2 channels of each just for testing purposesl

They are all pretty easy to assemble, just basic soldering skills required. They are compact but spacious enough to be comfortable. The top one is the biggest, but its only 1-1/2 x 2-1/2 inches. And the screw terminals make it pretty easy to wire up under the layout or wherever you might choose to put it.

Eight days is impressive, my lighting modules were held captive by DHL for over three weeks!  I'm going to specify a different shipper for the next order!

Very nice!

Hopefully @rtr12 will pick up on this and put your work on the Electrical reference post.  I can only hope folks understand the significance of this.  That is, the availability of low-cost relay modules for about $1 per relay is essentially unbelievable in our hobby when the "typical" price is about $10 per relay for controlling O-gauge accessories.

Rod is really getting into this electronics game, we've created a monster!

@gunrunnerjohn posted:

Rod is really getting into this electronics game, we've created a monster!

Hah, I've been called way worse than that! Seriously, its been loads of fun creating stuff that seems to work, and has an application in our hobby.

On a side note, I think I'll clean up all the files for all 3 boards and re-post them all together in one spot for ease of finding.

Rod

Well after a hiatus of several months I resurrected this thread and soon discovered that it would likely benefit with some sort of introduction to the two types of multi-relay boards available, and the 3 types of trigger boards we devised here, that make working with them easier. To this end the pdf file "3 Types of Relay Trigger Boards" is attached below. It will hopefully provide a fairly smooth leadin as to where and when you might want to use them around the layout.

I also re-attached the original gerbers created last spring and re-tagged them Type A, B & C for easy identification, along with the original How It Works pdf for Type A.

I have not created BOM's for the 3 board types as it's pretty easy to take the component values off the board silkscreens, or the circuit diagrams in the 3 Types of Relay Trigger Boards pdf.

Again I want to thank Stan2004 and the other forum members who pitched in and helped this happen last spring. These boards do seem to work very well!

Rod

Hi Rod,

Nice project here, guess I missed this one earlier. Looks like it could be really useful to many, especially with no Arduino knowledge needed. Anyway, saw the request by @stan2004 above to add this one to the projects list, so it's been added as #20 on the list. Please take a look and let me know if I need to change/fix anything. Hopefully, I didn't butcher the description too badly?

@rtr12 posted:

Hi Rod,

Nice project here, guess I missed this one earlier. Looks like it could be really useful to many, especially with no Arduino knowledge needed. Anyway, saw the request by @stan2004 above to add this one to the projects list, so it's been added as #20 on the list. Please take a look and let me know if I need to change/fix anything. Hopefully, I didn't butcher the description too badly?

I think you captured it quite well Tom! Nicely done.

For estimated costs, that would depend a lot on where you get the boards made, and how many channels you populate. But it should not be more than $5 each in any event; to as low as $1.50.

Rod

Thanks and glad you approve.  Just added those estimated costs for the project to so I think it's finished now.  Just about forgot how to add on to that post, but it came back after some fiddling. During the re-training session I found and fixed a couple of typos and punctuation errors so all was good.