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I have a DS-1302 RTC module but how to use it?
I recall Jon Chandler made a vu meter clock but what he used for timing?
Am planning on a clock that has no hands, just LEDs but precision would be nice.
Will need to purchase some diffused LEDs.
After printing out the pattern for 24 x 24 inch plexiglass I am going to downsize so only 2 PCBs are required so looks like 11 x 11 inches for the clock face.
I should have known the dozen posts I made trying to explain how to implement this concept would be a total waste of my time. I've fallen into this trap far too often.
I would make a recommendation, but even a simple recommendation seems to require multiple messages to explain, and then you'll decide on some whack-a-mole scheme anyway, so why bother.
I located in my parts pile numerous ribbon cable connectors so I plan on using them. As per post#28 I am planning on swapping out the 2n3904 transistors for MOSFETs.
Just doing the 2 board layout sounded easy but!
I played around with the 2 board idea for my own enjoyment. This is how I'd do it. One board serves for both halves, with the micro location only populated on the right side. in order to keep to an 8 x 9 matrix, the green and red LEDs are in the same matrix, which requires separate resistors for each LED to allow matching the intensity of the green and red LEDs.
Mapping of the LEDs is a little weird, but this will be sorted out in the software.
However, if the plan is just to illuminate one LED for hours and one for minutes, unless a clock face is drawn, it will be extremely difficult to tell the time with no visual reference.
The boards would be connected with two pairs of right angle male and female headers. These provide both mechanical and electrical connections.
Well here is my updated schematic. It is a revised schematic of post#28 that I had to use but post#28 required more pins than are available.
I now have one resistor per LED.
Working on two board layout
Please you proper symbols for supply voltage and grounds and NOT bus labels. If you recall, this got you into trouble on your last project one of the bus labels was misspelled as "GRD". This makes your schematics difficult to understand. Also, your schematic has a lot of point where tracks don't quite connect. You may know what you meant, but the net list will not.
I'm not sure we're on the same page regarding "two boards" vs "one board used twice". I've added some notations to my schematic to clarify. The same board will be used twice, rotated by 180 degrees. Locations will exist for the microcontroller on both sides, but only the right side will be populated. Look at the connector at the bottom. Connections for columns 5 - 8 are made through this connector. These will be made to columns 1 - 4 in the right-side-up board, but when it's flipped, those are columns 5 - 8.
Schematics for the two boards together are shown below. The boards are identical, except the left will not have the microcontroller and associated components (i.e., it has only LEDs and resistors).
Will make spme changes. This post cleared up several questions. ONE massive mistake I have made is the board size is 200mm x 200mm so I need to reconfigure the size or ?
I know I need to redo the schematic to accommodate the size of the boards.
One thought came to mind is make one board with microcontroller etc and several boards with only the LEDS.
You STILL seem to be missing the point. Several in addition to the fundament point.
You said you wanted a 300mm clock. Therefore the board is 150mm wide by 300mm tall If you're using this one board × 2 copies approach.. Each board is a hemisphere (half circle).
BOTH boards are exactly the same, except all of the microcontroller parts are left off of the left side. This is important – if you put a microcontroller and its associated components on both sides it WILL NOT WORK. Two boards make up one clock.
The schematic will only include LEDs and resistors for half the clock, with connections for the other columns routed to the other half. See the connector at the bottom of the schematic.
The board must be layed out so the straight edge is rotated 3° clockwise. This must be done so the LEDs at 12 o'clock and 6 o'clock aren't straddling the joint between boards. Why 3°? 60 LEDs spread around 360° = 6° between LEDs and you need to split the difference.
End of free design service. I have spent many hours figuring this out and explained it as clearly as my faculties allow. Either you get it or you don't.
If there's a will, there's a way;
Hopefully this will work. I need to add some more board interconnects.
By vertically flipping the boards (only 2 required) and clipping off the tab after flipping.
This should make the eyes in the correct spot.
I am going to print this out them cut out the board outlines (only 1 board outline is showen but the left side bottom is flipped vertically as well with the tab cut off.
I don't really understand your plan, but that's OK. I don't have to. I've offered my advice. Hopefully, you've understood enough of what I've suggested to make it work.
If you're only making your clock 200mm x 200mm, check the cost to do a 200mm x 200mm board. The cost savings of using multiple smaller boards my not be worth the hassle.
Yeah, this is a no-brainer. At JLC, a 200mm x 200mm board is 20 buck for 5 boards. Pay the extra price. I think the chances of your success with multiple boards is pretty slim.
JLC is also doing full-color silk screens. Make a jpg picture of exactly what you want and they will print it on the board. You'll have to read their documentation to see exactly how to do it.
Sorry for the distraction of the multi-board layout. If your design is amenable to being laid out this way and if you completely understand the concept, it's a cool way to achieve a large design cheaply. I think neither of these is true in this case.
After considering all the options discussed and laying out all the suggestions I ended up with a 200mm x 200mm board all surface mount. Now to recheck everything again.
Since I've somehow lost this post twice now, here's the short version. Can't tell much with the silkscreen layer on, but I can see many areas where your traces are too close together.
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