Instructables

So this Lazy Old Geek (LOG) decided to start making my own PCBs (Printed Circuit Boards). There are a lot of good Instructables to do this but I couldn't find one to do the whole process the way I wanted to. As some of you may know, I am a stickler for details. Here are some of my 'requirements':

 

Eagle Cadsoft for schematic and board

Single sided PCBs (copper on one side only)

Toner transfer using a Laser printer

Muratic Acid for etching

 

The examples I’m using are an audio amp, a battery protection circuit and my weather station Arduino shield.

 
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Step 1: Eagle Cadsoft

CAD(Computer Aided Design) software is used to create a schematic and convert the schematic to a PCB.

Eagle Cadsoft software is available at:

http://www.cadsoftusa.com/

 

There is a lite version that is free and what I am using. This version will limit you to PCBs 100x80mm(4x3.2 inches) and two layers(Top and Bottom). So far this is adequate for my purposes. I’m not going to go into a lot of detail as there are a lot of other tutorials that do a better job. I will add some tips that I used.

 

Here is a great Instructable for newbies:

http://www.instructables.com/id/Draw-Electronic-Schematics-with-CadSoft-EAGLE/

 

Basic: Install and run Eagle Cadsoft, start a new project and draw schematic.

TIP: I installed it on a Windows 7 machine. It installed under:

C:\Program Files (x86)\EAGLE-6.2.0\

 

The first step is to create a schematic.

 

Schematic Capture:

Components have two basic characteristics, electrical and physical: When adding parts or components, make sure you have the right package. The package is what it will look like on the PCB.

Integrated Circuits have two basic types. SMD is surface mount. But most hobbyists use through hole. These are the ones with the pins with long legs. See picture. These are sometimes referred to as DIP(Dual In Line Package).

Resistors and Capacitors: The above Instructable has some great tips on selecting these. Most can be found in the resistors library. Resistors can be installed vertically to save some space.

Finding library parts that match what you buy/have can be a challenge especially if you use ebay like I do. The stock library has a lot but it is often confusing and hard to find what you are looking for. I do a lot of internet searching to look for Eagle Cadsoft library parts.

Libraries I added:

            Sparkfun https://github.com/sparkfun/SparkFun-Eagle-Library

            AdaFruit http://www.ladyada.net/library/pcb/eaglelibrary.html

            gm http://gaussmarkov.net/wordpress/tools/software/eagle/eagle-2-libraries/

 

The .lbr files are added to this directory on my PC:

C:\Program Files (x86)\EAGLE-6.2.0\lbr

 

TIP: I like to use all libraries to search for parts. To use all libraries, on the Eagle command line type use *. See picture for command line

TIP: Do not use Wire to connect components. Use NET. Net will automatically form junctions when terminated on pins or other nets.
Tip: Some ICs do not show power and ground connections. Put the part on the schematic, right click on it, select Invoke,select P (Pwr) and add connections. Then you can place it on the schematic
Tip: move a cluster of components. Use the group (select box) to select a rectangular group of parts, then select Move tool. CNTRL+RIGHT-CLICK, move the whole selection to where you want the group to go.

Advanced: You may have to create or modify your own library part. Here's a good Instructable:

http://www.instructables.com/id/How-to-make-a-custom-library-part-in-Eagle-CAD-too/

It is really hard to do this. Avoid this if you can.
nbeched1 year ago
A few additional tips:
A pencil eraser works great. It is a mild abrasive, but not nearly as hard as sandpaper or steel wool.
So pencil eraser followed by a bit of solder flux usually does a great job.

After soldering, clean off the flux with alcohol or acetone (some types of flux are better dissolved in alcohol). Do a thorough job, use an old toothbrush.

Then use something called "Conformal coating". It adds a layer of silicone or acrylic (2 most common types) and "seals" the copper, consequently making your board practically waterproof.

Awesome instructable.
Than you.
msuzuki777 (author)  nbeched1 year ago
Good idea, pencil eraser. I've also used it for cleaning PCB contacts like on PCBs that are plugged into computer motherboards.

I do try to clean off my PCBs with alcohol but often forget.

Conformal coating, I probably won't ever do, though maybe I should. I guess it's just cause I'm LAZY!

LOG
Well, laziness drives technology forward...
Nothing wrong with that :)

This is one of the most complete step-by-step guides I've ever seen.
Thank you.
msuzuki777 (author)  nbeched1 year ago
Thanks, I like to be really detailed.
Part of it is from getting frustrated reading some Instructables and not being able to figure it out.

And sense I'm getting OLD, sometimes I have to go back to my own Instructables to remember how I did something.

LOG
Well, laziness drives technology forward...
Nothing wrong with that :)

This is one of the most complete step-by-step guides I've ever seen.
Thank you.
Well, laziness drives technology forward...
Nothing wrong with that :)

This is one of the most complete step-by-step guides I've ever seen.
Thank you.
omnibot1 year ago
Nice writeup.
I use Sodium persulfate because it's environmentally friendly-ish and the only thing widely available in Sweden. In my experiments I've noticed I can speed it up by adding tablesalt or white vinegar. When etching iron or steel with Sodium persulfate and tablesalt I got Ferric Chloride as a byproduct which was really useful to etch copper with :)
msuzuki777 (author)  omnibot1 year ago
Haven't heard of Sodium persulfate before.

LOG
nbeched1 year ago
Awesome instructable.
One suggestion: do not use JPEG. It is only good for photos.
BMP is the best, but uncompressed, so the file is large.
PNG is lossless compressed format that is ideal for this purpose.

Also, there is no need to turn off the layers and export, you can use CAM (Computer Aided Manufacturing) toolkit that is built in to Eagle and just select the bottom layer and the output "device" to be an image. I don't have it installed on this machine, so can't tell you the exact procedure, but you can start it straight from the board editor.
Experiment with this and you'll like it more than export since this is made specifically for manufacturing shops and it exports everything "properly" so to speak (correct board dimensions, etc).
msuzuki777 (author)  nbeched1 year ago
Thanks for the info on file formats. I have stopped using JPEGs because I figured another translation process wouldn't be beneficial. But I didn't know PNG was lossless.
I have a newer Instructable on PCBs:
http://www.instructables.com/id/Vinyl-Sticker-PCB-How-To/
I'll look into the CAM stuff.

LOG
nbeched1 year ago
Once again, the CAM allows you to select just the layers you need and export them to gerber or image format.

You'll have even better results with it.
Scumm71 year ago
A couple write-ups I've read recommend printing on the parchment paper used for baking.
msuzuki777 (author)  Scumm71 year ago
I just completed a different version using vinyl:
http://www.instructables.com/id/Vinyl-Sticker-PCB-How-To/

I have heard of using parchment but seem to remember a lot of discussion about types and brands to use. Right now I'm pretty happy with my vinyl.

LOG