So the RTC is essentially just a crystal attached to a battery and wired up to a 24 pin din?

No, it's like a microprocessor doing time functions and providing the signaling to the computer. The main chip is on the bottom of the PCB. The crystal is a clocking reference since it's not integrated in the chip. Probably cuts costs and allows better selection/precision parts. It's a package adaptation since the original foot print of the pin spacing is huge and not really in use anymore. Externalizing the battery in this custom project makes it easier to maintain in the long run. Because for how long are we going to find old stock or reliable reproductions? Just a good retrofit imho, even if it ends up costing more than some obscure overseas source.

Auzner wrote:

No, it's like a microprocessor doing time functions and providing the signaling to the computer. The main chip is on the bottom of the PCB. The crystal is a clocking reference since it's not integrated in the chip. Probably cuts costs and allows better selection/precision parts. It's a package adaptation since the original foot print of the pin spacing is huge and not really in use anymore. Externalizing the battery in this custom project makes it easier to maintain in the long run. Because for how long are we going to find old stock or reliable reproductions? Just a good retrofit imho, even if it ends up costing more than some obscure overseas source.

Okay, that makes more sense. I was looking at his plans and part list and completely missed the part where he was attaching them on top of the chips.

Finally back from the North Pole. Ordering shipping boxes tonight and testing the remaining modules throughout the day.

If all the current modules work, that'll be 9 of them ready to ship to potential buyers. I also have most of the supplies to assemble 40 more, just need to order the PCBs.

I am now using the unit in my test board. No problems to note.

That's 8 modules tested and ready to go, 1 more in testing. Just waiting for the packaging to arrive.

Buyers may need to find a CR1216/CR1220/CR1225 battery (I only have a small handful of them, some of which I'll keep for testing the new modules). Shouldn't be too hard at any place that services watches (even Walmart should have those).

If anyone's interested, PM me.

I was just about to put a new order for PCBs (~30-50 of them) when an idea dawned on me.

Would there be any interest if I installed a 'clear CMOS' jumper or microswitch right on the module itself? It's about $1 in extra hardware.

I understand that some motherboards seem to lack said jumper so it might be convenient.

Wouldn't removing the battery clear the CMOS?

... damn, can't believe I forgot that. Removing the battery and draining the caps does work. 🤣

Oh well, I'll leave the footprint there and unpopulated just in case. 😀

Current status?

Sorry to bump this thread, but I am very curious to know the status of this product and if it's still available to order?

is the schematic somewhere avaible ? i also intressed into rolling a punch of PCBs..

Well there's this. https://oshpark.com/shared_projects/DgExxcyH

It looks like it can still be ordered.

well, if anyone goes ahead and makes a batch, I'm in for a couple.

Sorry I haven't been around lately; work has been completely insane since my last post on this thread and I'll be spending no less than 3 months offshore and offline this summer. I still have a bunch of said modules ready to go, unfortunately shipping is so prohibitive that it really makes it pointless.

Seriously, to have tracking, shipping to the US ends up being ~2x the price of the chip itself. This does not leave me with the best opinion of CanadaPost.

Brickpad, that's actually an old version. I'll post a link to the newer one this evening if anyone is still interested. There's not much difference, the newer one just uses crennelations and is easier to assemble.

If someone wants the fully-finished version and doesn't mind shipping charges I can ship the ~20 I have assembled and tested as well.

edit: Good News! chitchatsexpress has just opened an office relatively closeby so this will likely make shipping charges drop dramatically. I'll update when I have more info. 😁

Brickpad wrote:

Well there's this. https://oshpark.com/shared_projects/DgExxcyH

It looks like it can still be ordered.

This is the newer version: https://oshpark.com/projects/NwcVatSK It sits ~1.6mm lower than the first version.

Where do you buy the DS12887 ? they are expensive ~7-9 Euro a Piece.
May we can do a group buy for PCB and DS12887, as the price will drop significant if i buy 25 or 50 Pieces at once.

Well there's this and several other places. If you don't mind waiting for a month to get them from China. Comes to just over $1/piece including shipping.
http://www.aliexpress.com/item/10pcs-lot-DS12 … e5-cba5fdb4e7d2

Is the 12885 compatible with the 1287/ 12887 though? The date code on that chip shows 1995, and I think that is a surface-mount chip and not a through-hole.

Maeslin wrote:

Brickpad wrote:

Well there's this. https://oshpark.com/shared_projects/DgExxcyH

It looks like it can still be ordered.

This is the newer version: https://oshpark.com/projects/NwcVatSK It sits ~1.6mm lower than the first version.

Thanks for the update! Is there a minimum order quantity? I will probably order 3-5 of them for projects and spares if / when they're available.

[edit]

I can assemble these myself if it's possible to order all the parts as one package?