IN-18 Modular Arduino clock progress

[Terry S]

Haven't had a lot of time to work on this, and still learning Eagle, but here is what I can show.

Space turned out to be tight for the original size board for the main 2 digit section, so on the left, I added an inch to ease routing on this 2 layer design. The 2 digit extension size remained the same as the original.

I also cleared up space by changing out the on-board 555 based HV supply for the one Mike M. sells -- at under $10 it's well worth the price and the vertical footprint saves loads of space. http://www.ebay.com/itm/151587665616

Also made provisions for Dieters colon tubes. Or you can construct your own colons using the thru holes provided.

Under tube lighting is a single 1206 LED of your choice. Most significant digit LED is separately controlled so it can be blanked when the tube is blanked.

Again, the clock can consist of one main module and one extension, or one main and two extensions. 4 or 6 digits.

The main module mates with any of the full size Arduino boards or clones. Software is open source and will need only minor mods to run the backlighting and colons, which will be controlled by previously unused Arduino outputs.

The schematics are a  little rough and not ready to show. The early layouts will be attached below.

Feedback appreciated.

Terry

[John Rehwinkel]

Haven't had a lot of time to work on this, and still learning Eagle, but here is what I can show.

Space turned out to be tight for the original size board for the main 2 digit section, so on the left, I added an inch to ease routing on this 2 layer design.

I know that feeling well!  I ended up splitting my 8 tubes into two 4-tube boards joined by right angle headers (same approach you went with).

I also cleared up space by changing out the on-board 555 based HV supply for the one Mike M. sells -- at under $10 it's well worth the price and the vertical footprint saves loads of space. http://www.ebay.com/itm/151587665616

I'm working on a "divergence meter", and ended up going with the vertical mount Tayloredge supply.  You're right, those vertical mount supplies do save room.

Under tube lighting is a single 1206 LED of your choice. Most significant digit LED is separately controlled so it can be blanked when the tube is blanked.

Looks like one tube has two LEDs in series, or is that the series resistor under the tube?

The main module mates with any of the full size Arduino boards or clones.

Nifty idea.  I started that way, then ended up embedding the Arduino on my CPU board.

Software is open source and will need only minor mods to run the backlighting and colons, which will be controlled by previously unused Arduino outputs.

I'll be going open source too.

Feedback appreciated.

I'd suggest adding some silkscreen legends for the parts.  You've got a few traces running very close to some edges, and even through the "keepout" areas around your mounting holes.  Might be worth trying to move those.  I see where you've worked your driving electronics in the bus area, that's tricky to do.  I'd be tempted to move a few of your traces to keep high and low voltage signals apart and save a few vias, but overall, I like it.

Also, fair is fair, so I'll share my in-progress design too.

Cheers,

John

[Dave]

I am thrilled to see you two sharing your work and stating that you will share the boards and software as open source.
I think that is just great !

[Terry S]

John,

 

Thanks for your suggestions and feedback.

 

There is a current limiting resistor under one of the tubes. I may move that. Does anyone know if a single LED is adequate for lighting an IN-18? I don't have a feel for that. I won't be populating the LED's on my boards except for experimentation purposes -- I dislike tube lighting. I think it looks gimmicky.

 

Yes I do have traces running thru the mounting hole keepouts. I'll probably try to clear those, although I intend to use plastic washers as necessary to isolate the mounting hardware.

 

I do have silkscreen ref designators and such, just not shown in my screen captures.

 

Traces near the edge -- yes also. I'd like to squeeze those in, but it's a trade-off with spacing of course. Some better pre-planning might have made the high/low voltages easier to isolate from each other. I thought I'd rationalized almost every via I could from the design, but I see now how a few more could go away. Vias are essentially free.... used to add cost to the boards in the "old days" ..... but some see them as mini-failures of the artistry of the layout. I used to share that sentiment, but no longer. I might spend hourse trying to eliminate 4 or 5 vias, and to what return on investment? I appreciate an elegant design as much or more than anyone, but sometimes the cost in time just isn't justified.

 

Your layouts are very nice. It's simply amazing how the smaller tube footprint helps keep it clean. And all thru-hole, no small feat. I cut my teeth on thru hole decades ago, but I bet I haven't done a non-smt design in 15 years.

 

Terry