Yes, correct, the unpopulated holes all look to be and measure the same, both rows of them. I was unable to fully seat the 3 pin header by hand, just barely got it started. It was harder than I thought from my first attempt at lining it up for fit. Ended up having to use a small pair of flat nosed pliers to fully seat it tightly in the holes. Just have to make sure the pliers clear bottom pins while pressing it through the PCB. 

With a magnifying glass and a meter I was able to trace the 3 holes used for the pin header to their connected components and got good continuity on all three pins! Checked each pin a few times to be certain.

I was even able to remove the 3 pin 'press fit' header without damaging anything. Had to gently and very carefully pry it up with a small screw driver. As another test, I reseated it a second time (still needed pliers) and it all checked out the second time as well. These seem to work quite well, great find GRJ! Looks like we have a winner here! 

That indicates you can actually have a "no solder" option if you assemble the boards.  That should reach more people.

For pressing the header in, you might consider a small piece of wood with 3/8" hole drilled in it.  Back the PCB with the wood, line the hole up with the three holes for the header, and use a vise to gently press the header in place.  I would use my press, but if you don't have one, a vise works.  Another method is using a drill press as a press.

That is becoming an option I'll be considering, these pin headers seem to work very well. And the reduced parts needed should be an advantage as well.

I'll look into the wood block suggestion. Sounds like a good idea there too. 


You just have to insure whatever is on the bottom isn't pressed by the backing, which is why I mention a small block with just the hole for the connectors.  With only six parts including the header, it would be pretty quick to assemble these boards.  Give yourself a few bucks for the labor and make a little package that doesn't require any soldering to install in the DCS-RC. 

From some of the stuff I've seen, a lot of people would love to be able to do something like this and not have to deal with soldering.

I think that's a good idea about the no solder PBWs, I agree that lots of folks just don't want to solder stuff and would like things that just plug in. 

You were too quick replying, I was editing to add the following so I re-did it.

Need to do some testing with the new component values and check that out. I guess I'll have to rely on my Hz readings with the DMMs. The flashing LED is not synching extremely well with the second hand on my watch. It syncs for a while then gets out of step for a while. I don't have any PCBs yet so I can't try it on my layout until then. 

I think that Hantek scope may be calling me here, that would be a good way to break it in. I have been eyeing it everyday at least once.     

Once you have a decent digital 'scope for stuff like this, you'll wonder how you lived without it!   If my ATTEN ever craps out, I'll be on the Internet ordering a new one.  I'd probably go for a Rigol model, I've seen and heard good things about their products.  However, currently the ATTEN is working just fine, and it's more than sufficient for what I do here.

FWIW, I test these with a little board with a socket and an LED, I just supply it 5V with a bench supply.  I do have a frequency counter that I can hook up to check the period, but it's just easier to grab the 'scope, so that's what I normally do.

Good point about doing it for multiple resets, that does make it easier to time it without expensive equipment.  Of course, for the design verification, I'd probably still want to know exactly what several samples do by actual measurement.

gunrunnerjohn posted:

Good point about doing it for multiple resets, that does make it easier to time it without expensive equipment.  Of course, for the design verification, I'd probably still want to know exactly what several samples do by actual measurement.

How is watching the LED blink not an actual measurement

GRJ, I've heard good things about Rigol as well, very nice. I am still an apprentice and will probably have trouble using the Hantek. I saw something the other day about the Hantek 70Mhz model ($199) actually being the 200Mhz model and could be 'unlocked' with some kind of tweak or something? That was over my head, also sounded a bit questionable? Think I'll stick with the 100Mhz one we were recently looking at, the bait is working and very close to setting the hook. 

I added an LED on the breadboard from pin 3 of the 555, what I was trying to time with my watch. I am not 100% confident the DMMs I have are measuring HZ as accurately as your frequency counter would? They do seem to be in the ballpark with the 555 calculator findings though.

Stan, all my watches are analog, I'm using Mickey's hands to do the synch test.  I was trying to make use of one of the new fangled features (Hz) on some of the DMMs I have accumulated, all inexpensive of course. Good idea on the smartphone, hadn't thought of that. I'll give it a try with the LED and blink counting. 

You guys are quick!  As a friend of mine always says, "anything worth doing is worth over doing".  I would like to test this in every way I can and will probably end up learning a thing or two in the process. 

Hey, just thought I would bump this thread and see where we are at getting this mainstream. While I don't have any aversion to soldering I do like getting a complete kit to build and wanted to know if this will be offered in a completed version and one that can be a builders kit. I have built one already (thanks GRG) and due to recent changes to the layout need another. If you have un-powered yards this is the ticket to keep locos dark and silent when turning on those tracks.

GRJ is correct. New 555 design is working on a breadboard, but untested in actual service. I'm waiting on some PCBs to actually test it with a DCS-RC on my layout. With nothing unexpected happening, should have something ready in the next week or two.

The plan is to offer complete kits that will need assembly (soldering) and also a fully assembled unit that needs no soldering, fully PnP (thanks to the 'push-fit' pin header that GRJ found). 

All the parts and PCBs are in. I have assembled a couple and been testing them on my layout that last couple of days and have had no problems so far. My initial order was mainly for testing to see how everything went, so far so good! I have a few already spoken for, but I still have several left (kit or assembled) from the first batch. The 'Press-Fit' headers seem to be performing very well here so the assembled version can now be a completely 'no soldering involved' version.  Both versions are PnP (no adjustments needed) as mentioned earlier in the thread.

For anyone that is interested in one of these: Please send an email to my profile email address and I will email you the ordering information.

If anyone wants to make their own, attached are the revised Diptrace files and Gerber files for the newer version.

DCS-RC Watchdog PBW 555 Timer Version Schematic & Parts

Schematic and Parts list are also included in the Instruction file (.PDF). 


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