SMD Version

[balzreber]

Hello liebman

I'm currently in the final stages of finishing an SMD version of your awesome AnalogClock.
I only use JLCPCB components, so the board should be orderable from there, almost fully assembled.
The current version is a 1:1 replica of your design.
I think I could make the design even simpler, and therefore smaller. But I have some questions for you about that.
Of course, I will share my design once it is finished.

(Image is wip)

[balzreber]

I finished the board. It's now 100% JLCPCB parts, including THT. So the board can be ordered fully assembled.
I got the footprint down to 70mm x 40mm.
I'm just waiting for a missing part to arrive at JLCPCB. As soon as that happens, I will place my order.
By now I pretty much found out what I needed to know by myself.
I plan to spit off my board into a separate reopo. I know I'm technicaly allowed to do that, due to this project running on an Apache 2.0 license. But it would be nice nevertheless to get an okay from liebman?! Maybe he could even reference my repo in the readme of this project?
I will create my repo after I'm able to get my board, so I can be sure that there are no errors.
I will post updates here until then.

[liebman]

This looks really nice! The only potential issue I see is programming the AtTiny85v, have you considered how your going to manage that? (will JLCPCB program them before assembly?)

[balzreber]

Good point. My idea was to program it "in-circuit". Something like in the image below.
Or do you see any circuit limitation that would prevent this?

[liebman]

It may work for the initial programming but after the fuses are set the reset pin will be disabled (its turned into a GPIO to detect power fail)

[liebman]

You will want to insure that programming is done at 3.3v (does that work?) or you will put 5v on some of the ESP8266 IO pins (SDA/SCL). Also possible issues with the RTC seeing signals on its pins while unpowered.

[balzreber]

I see what you mean. I think I will add some dip switches to completely isolate the attiny85 just for programming. Thanks for your thoughts on this @liebman

[liebman]

maybe it would be smaller to switch to THT for the attiny and socket it? This is why I went with THT for it. Made it easier to pop out and use an HV programer to reset the fuses so it could be programmed again.

[balzreber]

That is a good idea. I didn't want to do that, so you can order the board fully assembled. And I don't think JLCPCB will socket the chip for me. Neither will they deliver it as a loose part. But since you need to order an Attiny programming board separately anyways, you may as well order the chip with that.
I will be back with a modified design.
Thank you so much for your help @liebman. As you probably noticed, I'm not an electronics engineer ;-)

[balzreber]

By the way, Is that okay with you @liebman ?

[alteredz]

Once this board design is finalized, I'd like to purchase a couple.
I'd prefer getting them with the chip already programmed.
Thanks, Pete

[liebman]

@balzreber I'm fine with that labeling.

Some assembly houses can pre-program MCUs as part of assembly, you may want to see if thats possible in this case. If so then you can put some SMD jumpers on the traces that lead to the attiny, that way if you needed to re-program it a second time you could cut these, program, and then solder bridge the cut.

Also the one thing that I found most difficult was finding clock movements that were easy to modify - and tuning the exact pulse timing and pwm level was a real challenge. I'll look later to find where I ordered these from.

[balzreber]

@alteredz I was talking to JLCPCB about that. They told me that they could theoretically do that. But they would have to look at the exact schematics to confirm (they do in-circuit programming, not pre-programing). And of course, it costs extra. And since they have to involve some engineers, the markup will be significant!
I'm currently changing the design to have a socketed Attiny. You can then buy a USB programming adapter (like the one in the image a few posts further up) and program the Attiny with that. It should be pretty much plug-and-play.
Of course, you can talk to JLCPCB yourself, I didn't ask for the exact price. And of course, you can order the same board from other manufacturers. It's just that my BOM will have JLCPCB part numbers in it. So you would need to change that.

@liebman thanks for the hint! I'm living in Switzerland. The home of clocks. So I hope I can get some good clockworks here :-)) But I would appreciate you looking up which ones you used nevertheless ;-) Thanks

[liebman]

I noticed that the blog link was broken - I've just updated it - it will provide a lot of info about the design. https://blog.taboola.com/analog-clocks-ntp/

[liebman]

This is what I had the best success with https://www.klockit.com/all-departments/quartz-clock-movements/quartexr-push-on-quartz-clock-movement-threaded.html