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 Post subject: leds
PostPosted: 14 Nov 2010, 04:41 
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Joined: 14 Nov 2010, 04:29
Posts: 7
I have just started using this program, doing ok but I am struggling with finding led patterns or modifing one to work. What I am wanting is a 10 led bar/dot pattern. It will be for a voltage moniter using the LM3914 chip. The hole pattern is the same as a 20 pin IC. But if you use just the chip pattern when you go to PCB it will not route to it. Any suggestions on how to solve this? I did figure out on my own how to get the Pot pattern to work. Thanks


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 Post subject: Re: leds
PostPosted: 14 Nov 2010, 15:11 
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Joined: 19 Jul 2010, 16:33
Posts: 126
"But if you use just the chip pattern when you go to PCB it will not route to it." ??? If you add "use" at the appropriate place, that sentence will still not describe your symptom. You did not actually what did happen. You did not say that you could route some traces and not others. You did not say your LM3914 was the 18-pin DIP. Maybe you would want to attach something that describes your situation.

You should make the connections in the schematic before routing. You did not say you did that.

Note that if your LEDs are all the same color, you might make your board more routable by turning the LED socket(s) 180 degrees and using the low LEDs for the high and vice versa. That would put the commoned anodes on the opposite side of the socket.

I made a a nice little board with the LM3914 DIP driver chip on the opposite side of a pair of 20-pin dips. The two DIPs actually had pins between each others pins. It was tricky hand soldering, Very compact. It would not be a good design for production however.

One comment about the LM3914... If using the one-LED-at-a-time mode, I suggest adding in pads for a resistor across the high LED in case you see a glow from that LED in your design. The driver puts a small current thu the high LED to allow cascading to the next chip if there is one.


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 Post subject: Re: leds
PostPosted: 14 Nov 2010, 16:49 
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Joined: 14 Nov 2010, 04:29
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yes I was not very clear on the led display I am using. Here is a link to the display http://search.digikey.com/scripts/DkSea ... -1236-5-ND The pin spacing is the same as a 20 pin two side IC, if i use the 20 pin IC pattern and draw in the schematics and lay it out the way I need to just using the IC pattern, when you convert from schematic to PCB layout it will not convert, because the pattern is blank or unassigned. Yes I am using the 18 pin LM3914. Can I attach the schematic lay out file here somehow?


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 Post subject: Re: leds
PostPosted: 14 Nov 2010, 17:14 
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Joined: 19 Jul 2010, 16:33
Posts: 126
Yes. You could attach your *.dch or *.dip files.

I have attached a library with a component I made for a 3-color bargraph for your experiments.


You do not have the required permissions to view the files attached to this post.


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 Post subject: Re: leds
PostPosted: 14 Nov 2010, 19:00 
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Joined: 14 Nov 2010, 04:29
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I finally got it figured out. I needed to change some things on my pattern. Another question. How do I seperate the part layout from the copper traces when I want to print out the traces, so I can transfer the pattern to the board for etching?


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 Post subject: Re: leds
PostPosted: 15 Nov 2010, 09:23 
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Joined: 14 Jun 2010, 06:43
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If you want to print out only copper traces, open Print preview, click on "Objects" button and unselect silk and other unnecessary objects. You will see result on preview window, then click on "Print" button.


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 Post subject: Re: leds
PostPosted: 15 Nov 2010, 20:12 
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Joined: 14 Nov 2010, 04:29
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Thank you for the help


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