My first PCB design - Page 1
Forum section: electronics / beginners

author: Hertog
author_rank: Newbie
timestamp: January 02, 2015, 06:39:46 pm
content: Hello people,I've been a long time follower of the EEVBlog on YouTube and I've been dying to try out some PCB design and manufacturing. So this morning I've cooked up a simple circuit with a 555 timer chip with a couple for 0805 resistors, caps and 2 LEDs and made this into a simple PCB design, using the autorouterI made this in EagleCad and i've included the ZIP file with the schematic and PCB design.And I just wanted to ask if anybody with a some experience in PCB design would care to look at my PCB design. Just to have an experienced eye look at my design and see if this PCB design is ready for production.Thanks for any tips / advice!Greets from The Netherlands!

author: free_electron
author_rank: Super Contributor
timestamp: January 02, 2015, 06:50:38 pm
content: one chip , three resistors , two caps and and led.. AUTOROUTED ? happy 2015 ... the year begins well...

author: Hertog
author_rank: Newbie
timestamp: January 02, 2015, 07:16:39 pm
content: Quote from: free_electron on January 02, 2015, 06:50:38 pmHaha thanks happy 2015 to you too!The reason I used the autorouter is just to get a feeling for how that works and what it exactly does. Newby remember?

author: katzohki
author_rank: Frequent Contributor
timestamp: January 02, 2015, 09:11:51 pm
content: Hey, I would autoroute a circuit that simple too.Edit:Post the Gerber.

author: idpromnut
author_rank: Unknown
timestamp: January 02, 2015, 09:53:46 pm
content: I'd suggest you generate and post gerbers as well (easier to see what the CAD package will actually produce as output, and easier for random people on the internet to view your PCB without the specific CAD software you usedAlso, I'd challenge you to take what the auto-router did, and try to manually re-route that board using less space.FYI, my first PCB was a couple of years ago, go have a lookhttp://clog.unrecoverable.org:8060/2013/04/board-update/andhttp://clog.unrecoverable.org:8060/2013/05/mosfet-driver-board-rev-c/.

author: daqq
author_rank: Super Contributor
timestamp: January 02, 2015, 09:56:18 pm
content: Well, the board IS ready for production, and it WILL work, but it's bad, sorry.If your goal is to learn something or try out something thenAVOID THE AUTOROUTER, fiddle around with the board, spend a day or so trying a better layout etc. While not critical, try to use different line widths for different signal kinds (thick for power, slim for signal). Play around with the layout, add some mounting holes, change the board shape/size, try different trace types... also, you can do this in one layer.Also, at least a small power decoupling cap (capacitor parallel to the power) wouldn't hurt.Also, look at your solder mask - it's the green stuff. I assume that you wish to contact the battery on the circular patern on the PCB - you have a trace going through that uncovered area.Also, be mindful of the orientation of your SMD battery holder and think in 3D - unless I'm mistaken, the user will have to get past the 555 and misc components in order to insert the battery into the holder the way it's currently oriented. Make sure it's oriented with an insertion direction facing outside of the board.

author: katzohki
author_rank: Frequent Contributor
timestamp: January 02, 2015, 10:20:10 pm
content: Hertog: You will find that some people have some serious hate for autorouted circuits. I use it a lot myself when I need to build a quick test or prototype something. We have a specific person for it when it is time to get ready for production. Sometimes you will have to make a couple changes when the autorouter is done, but it can help you to learn component placement tricks by seeing what it has to do to connect them. Post the Gerber and more will look at it I think.

author: sunnyhighway
author_rank: Frequent Contributor
timestamp: January 03, 2015, 10:42:06 pm
content: Not sure what kind of CR2032 holder you wil be using, but you might want to double-check if it is possible to put the battery in.

author: metalphreak
author_rank: Frequent Contributor
timestamp: January 03, 2015, 11:58:23 pm
content: Screenshots of board and schematic attached.You should really do this if you want other people to look at it, rather than having to download the files and open in Eagle (you'll find most people can't be bothered!). JPEG or print as a PDF at least.

author: c4757p
author_rank: Super Contributor
timestamp: January 04, 2015, 12:12:38 am
content: Quote from: katzohki on January 02, 2015, 10:20:10 pmThis is hisfirstPCB. You don'tlearnanything by having the computer do it for you. Auto-anything should be for people who are already experts at that thing...

author: metalphreak
author_rank: Frequent Contributor
timestamp: January 04, 2015, 12:24:00 am
content: That part for the battery holder isn't very good. You have a small square in the middle where the copper is exposed, with the rest of the battery surface protected by the soldermask. The surface of the battery is flat, and will sit on the soldermask raising it up above the exposed copper that you intend to act as the negative/ground terminal. The stopmask should really be a large circle the same size as the battery (you'll then need to move the V+ trace so it doesn't sit under the battery).The ground connection to the battery has to go all the way down, to the left, and up that skinny section of the plane before it actually connects to any of your devices. It is cut off at the top by the two V+ traces. If you are using the battery holder attached below, then only one side needs to be connected (if you want to get rid of the airwire showing in Eagle you can run a trace from the right pad to the left pad around the *bottom* of the holder so it doesn't cut off the ground plane - that eagle part isn't setup so that it knows the two pads are electrically connected through the part itself)Don't be afraid to move and rotate the capacitors and resistors to get a nice trace layout (something you'll learn as you go, if you do the trace routing yourself! Part placement is one half of doing a nice trace layout)

author: free_electron
author_rank: Super Contributor
timestamp: January 04, 2015, 01:45:35 am
content: i see you are trying to maintain some symmetry in placement.try this :rotate r2 180 degrees , now in your schematic swap led1 and r2 in place.you will now be able to place the following chain :r2 , led1, led2 , r1Wait.. here we go :

author: bugs
author_rank: Contributor
timestamp: January 04, 2015, 12:48:46 pm
content: This prompted me to registerHello form a fellow countryman!This is a great start of 2015!Why not try to make go for a single layer design and try to etch it yourself? You are only using SMD components, so no drilling required, just nasty chemicals.Have fun, make mistakes!!!