Wayne Yamaguchi talks home-made PCBs

My buddy Wayne Yamaguchi sent a little update on making printed circuit boards (PCBs) at home. Wayne always was the expert on toner transfer PCBs. This is where you print your Gerber art on a special film. Then you use an iron or a hot roller to transfer the printer toner from the plastic film to the copper-clad PCB material. The printer toner becomes the resist that keeps the acid away from the copper foil. Wayne has also figured out how to use a sponge to rub the ferric chloride on the board, so the copper etches away in seconds, not minutes.

I gave this a brief mention in an article about prototyping years ago. Wayne just keeps on improving this process and I hope to give a complete update soon. Wayne is also the guy that figured out PCB-Pool in Ireland was doing good work, as well as the USA triumvirate, Proto Express in Silicon Valley, Advanced Circuits in Colorado, and Sunstone (PCB123) in Oregon. Lately Wayne has been a fan of OSH Park up in Oregon. They operate like a community, where they take a bunch of PCB orders and panalize them on one substrate, so you can share the cost with a bunch of other people. For Wayne’s small boards, this can be ideal.

Wayne Yamaguchi holding a PCB he had made by OSH Park. Before stage this he makes his prototypes with toner transfer and acid etch.

So here is Wayne’s latest missive:

“Many of you know I still make my own PCBs at home. I think I just tweaked or ironed out a nagging issue. Sometimes I would lose some toner during the process of putting it on the PCB. Using the GBC laminator I’ve had reasonable success and I finally think that putting the board through once is insufficient to apply pressure across the whole board. I put the board in offset 30 degrees and then a second pass with the board turned offset -30 degrees. Putting the board through the laminator at different angles ensures all of the board gets heated and pressed.

“Here’s a board I made a week ago and now it’s aged and somewhat tarnished. You can see the test patterns in the circuit and one test pattern outside of the circuit board. All test patterns came out. The test pattern has an 8 mil trace, 6 mil trace, 4 mil trace and a 2 mil trace. Of course they all get flattened out during the process, but, the 2mil really had little toner and was surprised how well it came out even if it was flattened.

Wayne Yamaguchi gets down to 2-mil traces with home-made PCBs done with toner transfer and ferric chloride acid etch.

“Rough measurements show the 2mil came out around 3mil and the 4 mil squished out to around 5.5mil and the 8 came out around 11 mil. Typically for prototypes I try and stay with 10mil trace widths.

“This particular prototype yielded some good info and with that info I’ve made a few changes and have sent out for real 2 sided PCB at OSHPark. The OSHPark order came out to a total $4.95. The boards were placed on a panel within a day or so and have been sent out to the fab shop. I might get the boards next week some time.

“The process is a slight derivation from Pulsar, who created this process a long time ago.  Frank at Pulsar is the originator and should get all the credit for the process.”

Well thanks Wayne, many of us still like to whip out a single-piece prototype before going to fab and this is a great way to do it. My only warning, gleaned from personal experience, is to not put any vias under surface mount parts. There are no plated-through holes with these home-made PCBs, so you have to solder a little wire into every via.

Wayne Yamaguchi on file storage and project management

I had lunch with my buddy Wayne Yamaguchi last week. He showed me the latest upgrades on an Atmel-powered nightlight he has designed. I met Wayne when I was consulting at HP in the late ‘90s. He took an interest in LEDs and left Agilent when he started making more money selling kits to convert your Maglite into an LED flashlight. Wayne was the guy that got me on OrCAD 7, and I still use OrCAD 9.2. Love those free vias.

Wayne Yamaguchi holds his prototype LED nightlight at the Pho Kim Long restaurant in San Jose.

Anyway, Wayne wrote me an email about how he stores files and manages all his projects. He was the guy that told me about 1Password as well. Wayne writes:

I stick with Microsoft Windows PCs and laptops.  I find most engineering-related tools run under this environment. Other people seem to know every word of every datasheet they read.  But I need a way to handle large volume of data, notes, documents, images, PDFs, and everything else related to a project or task.

I use Dropbox for key data storage and sharing.  I have access to all my design files from any system or laptop I use.  In conjunction with Dropbox I use Evernote and my primary note/task/organizational tool.  There are many cloud storage solutions like box.com, Google Drive, and others.  But, Dropbox and Evernote work together. With Evernote configured correctly I have all my projects documentation, notes and current status in Evernote.  I can easily start or stop a project, and I can resume a project with the minimal effort.

I can access Dropbox files or Evernote from any pc, notebook, cellphone or tablet that I have.  I rarely use a USB stick to carry data or project info from one PC to another. That goes for my Orcad schematic and layout files, Solidworks design files, spreadsheet, pdfs and everything else related to a project. I keep them either in Dropbox (schematic, PCB, Solidworks) or in Evernote (notes, status, links, web site clips).

Once you have one or two tablets and a desktop you should have a central location for data. If you don’t do hardware or software development this is still important.  It makes sense to store files of extreme importance it so they are accessible on more than computer.

This has helped my writing Atmel code in the house while simulating and testing it in the garage.  When I am ready I can walk out to the garage, fire up the laptop, and burn and debug with the same files without having to transfer them in any way.  By the time I re-compile inside the house and walk into the garage the new files are already synced and ready to burn by the time I get to the garage laptop.

The same is true for my CNC mill.  I can edit my 3D file and generate new G-code and then have direct access to them on the PC that drives the CNC mill.  No transferring of files manually.  It’s all automatically synced.

Now as for me, I am a lot more scared of keeping my stuff in the cloud. I tend to side with GNU founder Richard Stallman, who says cloud computing is a trap. With the recent relations about PRISM, and the fact that the next world war will be a cyberwar, with foreign countries stealing our data and files, well, have a slightly more paranoid data storage method. I keep everything on a mirrored NAS (network-attached storage). I use Synchromagic to duplicate the data on my CAD machine, my audio-video production machine, and my home-theater laptop.

I also duplicate the one terabyte of my life’s work on a little USB hard drive. I keep one hidden at home and one in my safety deposit box in case the house burns down. I update them once a month. I don’t try to synchronize the files; I just use the program to make sure all the copies are coherent with the NAS. I keep my Thunderbird email profile on the NAS, so that I can read email from any of my home computers. I tried to do that with my Firefox profile, but it is a pain since the upgrade status can be different and then you break the profile. So I just keep a “master” Firefox on the NAS and copy the latest bookmarks and such to it.

And back to passwords, I asked one pal what he does, and he advises to just make an encrypted USB stick. He makes different 15-digit passwords for everything he has, and keeps them all on the USB stick. He then plugs it in and does a cut-and-paste into the applications, with another cut and paste of anything handy to push the password out of the buffer.

I really like the YubiKey, a 2-factor hardware system that my FastMail email service supports. With this type of system, the user needs to be in physical possession of the USB key, and he has to go to the bank website or application that supports it. Then when you press the button on the YubiKey, it sends a one-time password, that changes every time, to the website taking your password. Even if someone is key-logging you, they can’t get in using the same password.