3D printing is a technique we’ve all been using for ages at home, or via Shapeways, but if you are designing a product, 3D printing will only get you so far. It’s crude, slow, expensive, and has lots of limitations. While it’s great for the prototyping stage, ultimately products manufactured in volume will be manufactured using another method, and most likely it will be injection molding. Knowing how to design a part for injection molding means you can start prototyping with 3D printing, confident that you’ll be able to move to a mold without major changes to the design.

Read the full article at Hackaday: Designing Products with Injection Molding in Mind

You’re a contractor and people are paying you to work in your pajamas. It’s a life of luxury, but when tax time comes, you are in a world of hurt and you wonder why you even do it. Taxes are tricky, but there are some tools you can use to make it less painful on your pocketbook. With planning and diligence, you can significantly increase the amount of money that stays in your bank account.

Read the full article at Hackaday: Life on Contract: Hacking Your Taxes

The nuclear age changed steel, and for decades we had to pay the price for it. The first tests of the atomic bomb were a milestone in many ways, and have left a mark in history and in the surface of the Earth. The level of background radiation in the air increased, and this had an effect on the production of steel, so that steel produced since 1945 has had elevated levels of radioactivity. This can be a problem for sensitive instruments, so there was a demand for steel called low background steel, which was made before the trinity tests.

Read the full article at Hackaday: Low Background Steel – So Hot Right Now

WTF Are Ground Loops?

March 9, 2017

These magical creatures crop up out of nowhere and fry your electronics or annoy your ear holes. Understanding them will doubtless save you money and hassle. The ground loop in a nutshell is what happens when two separate devices (A and B) are connected to ground separately, and then also connected to each other through some kind of communication cable with a ground, creating a loop. This provides two separate paths to ground (B can go through its own connection to ground or it can go through the ground of the cable to A and then to A’s ground), and means that current may start flowing in unanticipated ways. This is particularly noticeable in analog AV setups, where the result is audio hum or visible bars in a picture, but is also sometimes the cause of unexplained equipment failures.

Read the full article at Hackaday: WTF Are Ground Loops?

The news has been filled with hate and anger lately. My normal sources of information are overflowing with it, and it makes the world seem like a terrible place.

This weekend I went to the Verona Public Library on a tour. My friend was so proud of it and wanted to show it off. I’ve been a fan of the Dane county libraries, but what I saw at this one was inspirational. If you want to skip to the point of the post, it is this: libraries are where we should be putting our tax dollars and attention. The community building, the learning, the understanding, the savings: the Verona Public Library represents who the average American is and what they do and care about, and how deep down we’re all loving people who just want to live a decent life and pursue interests like raising children and fantasy football.

Everything about this library is finely tuned to be awesome. The building is gorgeous and spacious. On walking in there is a book return with an automatic sorting machine that reads the tag and deposits the book into a specific bin for shelving. I know this because it’s behind a huge glass window that shows it off. Also near the entrance is a section for Wisconsin authors, popular new releases, and books for sale. My friend showed me where she votes, and the table that had all the appropriate documents for filing taxes. There was a computer lab, a reading room with a fireplace and all the latest magazines and newspapers. We walked by a giant shelf full of holds for people to pick up the books they had reserved online. The movies section rivaled Netflix (maybe not in volume, but definitely in the number of quality films, and many that weren’t available to stream). For adults, this place had everything, and if they didn’t have it, you could use the inter-library loan program and get it delivered there.

Then we went in the kids section. It was chaos, but perfectly organized for it. A giant castle in the center had little nooks for reading, and play areas distributed around the giant room were loci for congregating kids, with seats around them for parents to rest and mingle. There were piles of toys and books. The books were organized by ages and categories, and so many of the categories were really powerful and important, like bodies, Jewish, military family, countries like Pakistan, Iran, Korea, and Vietnam, and parents were reading to their kids from seats all over.

THAT’s what this country is and should be about. Teaching our kids about other cultures, learning about ourselves and others, and sharing resources. The place was safe and full of people who cared and weren’t afraid of other people and who understood the value and benefits of the library.

As we left, we checked out at the kiosk, where we were able choose our language to start the process. We chose pirate, because how freaking awesome is it that pirate is an available language at a kiosk? I still get a little choked up thinking about the library. There was so much love in that place. So much intellect and opportunity and community. That’s who we are as people, not this crap on the news every day.

Nerd Nite January 2017

January 26, 2017

I had the honor of presenting at Nerd Nite Madison in January of 2017. Here’s my talk:

There are certain design guidelines for PCBs that don’t make a lot of sense, and practices that seem excessive and unnecessary. Often these are motivated by the black magic that is RF transmission. This is either an unfortunate and unintended consequence of electronic circuits, or a magical and useful feature of them, and a lot of design time goes into reducing or removing these effects or tuning them.

You’re wondering how important this is for your projects and whether you should worry about unintentional radiated emissions. On the Baddeley scale of importance:

  • Pffffft – You’re building a one-off project that uses battery power and a single microcontroller with a few GPIO. Basically all your Arduino projects and around-the-house fun.
  • Meh – You’re building a one-off that plugs into a wall or has an intentional radio on board — a run-of-the-mill IoT thingamajig. Or you’re selling a product that is battery powered but doesn’t intentionally transmit anything.
  • Yeeeaaaaahhhhhhh – You’re selling a product that is wall powered.
  • YES – You’re selling a product that is an intentional transmitter, or has a lot of fast signals, or is manufactured in large volumes.
  • SMH – You’re the manufacturer of a neon sign that is taking out all wireless signals within a few blocks.

Read the full article at Hackaday: PCB Design Guidelines to Minimize RF Transmissions

Chances are good that you’ve already lost some blood to thermoforming, the plastics manufacturing process that turns a flat sheet of material into an unopenable clamshell package, tray inside a box, plastic cup, or leftover food container.  Besides being a source of unboxing danger, it’s actually a useful technique to have in your fabrication toolchest. In this issue of Tools of the Trade, we look at how thermoforming is used in products, and how you can hack it yourself.

The process is simple; take a sheet of plastic material, usually really thin stuff, but it can get as thick as 1/8″, heat it up so that it is soft and pliable, put it over a mold, convince it to take all the contours of the mold, let it cool, remove it from the mold, and then cut it out of the sheet. Needless to say, there will be details.

Read the full article at Hackaday: Tools of the Trade – Thermoforming

Having finished the Tools of the Trade series on circuit board assembly, let’s look at some of the common methods for doing enclosures. First, and possibly the most common, is injection molding. This is the process of taking hot plastic, squirting it through a small hole and into a cavity, letting it cool, and then removing the hardened plastic formed in the shape of the cavity.

The machine itself has three major parts; the hopper, the screw, and the mold. The hopper is where the plastic pellets are dumped in. These pellets are tiny flecks of plastic, and if the product is to be colored there will be colorant pellets added at some ratio. The hopper will also usually have a dehumidifier attached to it to remove as much water from the pellets as possible. Water screws up the process because it vaporizes and creates little air bubbles.

Next the plastic flecks go into one end of the screw. The screw’s job is to turn slowly, forcing the plastic into ever smaller channels as it goes through a heating element, mixing the melted plastic with the colorant and getting consistent coloring, temperature, and ever increasing pressure. By the time the plastic is coming out the other end of the screw, and with the assistance of a hydraulic jack, it can be at hundreds of tons of pressure.

Finally, the plastic enters the mold, where it flows through channels into the empty cavity, and allowed to sit briefly to cool.  The mold then separates and ejector pins push the part out of the cavity.

Read the full article at Hackaday: Tools of the Trade – Injection Molding

A lot of people assume that the product development cycle involves R&D, outsourcing to a Chinese manufacturer, and then selling the finished product. It’s almost ingrained in our heads that once a prototype has been developed, the next step involves a visa and airplane tickets. Here is a guide that will explore a few other options, and why outsourcing may not be appropriate for everyone.

First, let’s talk about goals. We’ll assume you’re not a large company, and that you don’t have a huge budget, and that you’re just getting started with your product and don’t have big volumes; a startup trying to sell a kit or breakout board, or a consumer electronics product. Your goals are the following:

  1. Validate your product in the market. Build a minimum viable product and get it in the hands of lots of users
  2. Get the most bang for your limited bucks. All money should go towards getting products out the door
  3. Reduce risk to your company so that any single failure doesn’t crater the whole operation and you can safely grow.

With that in mind, what are your options?

Read the full article at Hackaday: Should You Oursource Manufacturing? A Handy Guide