Christmas Star project

[Visitor]

What's going on with RA6/7 in your diagram? Is there supposed to be a crystal there?

It would have taken slightly longer had I included the crystal Oops.

I drew the diagram just to show how a nice schematic can look.

 

[Nigel Goodwin]

It would have taken slightly longer had I included the crystal Oops.

I presumed you're missed it off - but does that chip not have an internal oscillator anyway - so leaving it off (and the two caps) would save cost and space.

I drew the diagram just to show how a nice schematic can look.

And it does! - very nicely done.

 

[MrDEB]

I found two 18f46k22 in the library, one is C219059 with a schematic symbol of actual footprint but the C89972 is same basic chip but the schematic symbol looks like a 40 pin dip.
I found that the attributes are same except the part number. Yes you can change the part number but??
Will make changes as per post #58
I like the schematic in post #53. Yes I used port flags instead of traces.
back to the drawing board

 

[Visitor]

You might want to check how many of those parts are in stock before you decide on a part..... Remember, no stock, there will be an empty footprint when you receive your boards back.

 

[Visitor]

You also may want to note – this PIC is available in 3 different square packages, one of which has 44 pins, 2 of which have 40 pins. The two 40 pin packages have different pinouts.

 

[MrDEB]

the C89972 is a 44 pin and last time I checked there were 2000+
referring to post #58, I removed the leds from that port, added caps and increased the 470 ohm arrays to 750ohm. I need to check on the correct arrays.

 

[MrDEB]

my computer crashed yesterday and star project files gone? having to start over and correcting mistakes.
Had to reinstall EasyEDA and the "library" is different but no big deal
I was looking at post#53 and wondering why RA6 has caps?

 

[tumbleweed]

The schematic in post #53 was setup originally for an external crystal.
Since you're using the intosc you can just delete the connections to RA6 + RA7 (along with the two C4 and C5 caps) and use those two pins to drive LEDS.

 

[Visitor]

EasyEDA stores your files "in the cloud" – log back in to EasyEDA using the same username, and your files will be there.

In post #53, an inset has been added showing the intended crystal.

 

[MrDEB]

been trying to SAVE a schematic etc BUT won't save?
Am using version 6.4.5 EasyEDA
maybe a glitch in program?
had to go into DOCUMENT RECOVERY to find the schematic I an looking for.
lots going on.

 

[Visitor]

Sigh.

Did you sign into your account??????

Data is stored on EasyEDA's servers. If you sign in, your file should be there waiting for you.

 

[MrDEB]

I signed in and finally found the file I am looking for
having issues with saving?
I made suggested suggestions except drawing all the traces. Looked at the 4 projects on the Easyeda site and IMO without all the lines it makes reading the schematic easier, at least that;s my opinion after looking at other examples.
I need to download a BOM and look at basic and extended parts etc. One component I was unable to locate was a .01 cap.
I found in the 6,4.5 version I can copy n paste components and they are renumbered automatically.

 

[MrDEB]

Oups! I looked over at the Amazon site for the 5 pack of USB wall adapters and the added cables are not USB -B cables but USB-C. They were type B a month ago.

 

[tumbleweed]

One component I was unable to locate was a .01 cap

A 1nF probably isn't a great choice... 100nF would be better. For reasons I won't bother with going into, you're actually better off with the largest value ceramic you can get in the case size you pick. I know that generalization will come back to bite me later in this thread...

And I'll try this again... have you tried driving two of the chosen LEDs in parallel using 680 ohms to see if it's acceptable?

 

[MrDEB]

I have lots of blue and white LEDs but not the 0805's but should work for testing.
this is a case where size does not matter?
ant other suggestions?
I am going to SHARE this project if anyone wants to build same.

 

[Pommie]

Just for clarification, are you planning on different coloured LEDs sharing a resistor?

Mike.

 

[MrDEB]

No one resistor connects to 2 LEDs in parallel.
I am going to breadboard same today just to see.
Same for the white LEDs, two LEDs one resistor.
I started laying out the pcboard earlier this morning and using the schematic I posted, it was easy to start with the resistor arrays and no having to redo the traces on the schematic due to twisted ratlines.

 

[MrDEB]

trying to SHARE this project but? it says it is private. Looking as to change from private to public.

 

[Visitor]

Apparently, EasyEDA is limiting sharing of projects because of spammers misusing it. Sad.

Tumbleweed isn't asking you if two LEDs in parallel will work – that's a given for reasonably matched LEDs (but still NOT a recommended practice). What he is asking you is whether the LEDs you will be using will be bright enough for your application with the resistor value you have selected. Testing this with some random LEDs you have won't prove anything.

 

[MrDEB]

I want to see the difference between parallel and single LEDs. Have gone as high as 750 using one blue LED.
For this project I think a dim LED is better than a bright.
I realize LEDs should be done in series, not parallel.
Using the one resistor with a high value should be safe in case one LED gives up the ghost.