Friday Hack Chat: Everything PCB

It was not too long ago that all PCB design packages were proprietary. Getting PCBs made was expensive, and if you tried to do this over the Internet, the best way was to download a board house’s proprietary software, design your board in their software suite, and send your boards off to be made. A 5 cm square board would cost two hundred dollars. I know this to be true because I’ve said it before, and no one has corrected me.

For this week’s Hack Chat, we’re talking Everything PCB with OSH Park. OSH Park is the leading creators of perfect purple PCBs. They have POGs, and for the last two weeks, they’ve been one of the few places you can send some Gerbers to and have it manufactured in a timely manner if you live in the US. Because China was closed.

For this week’s Hack Chat, we’re going to be talking about everything PCB. How do you do castellated holes? How do you mill slots and square or otherwise non-round holes? Internal cutouts? Stop mask expansion? Artwork? Panelization? Why purple? More POGs!

Our guests for this chat will be [Dan Sheadel] and [Drew Fustini] of OSH Park, and they’re going to be there answering all your questions. [Dan] has been around OSH Park from the beginning and enjoys designing tiny useless robots and mentoring students building better ones. [Drew] is an Open Source hardware developer, firmware designer, a BeagleBoard board member, and is usually found at hardware meetups wearing purple.


Our Hack Chats are live community events on the Hack Chat group messaging. This Hack Chat is going down Friday, March 2nd at noon, Pacific time. Want to know what time this is happening in your neck of the woods? Have a countdown timer!

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

These Small PCBs are Made for Model Rocketry

Model rocketry hobbyists are familiar with the need to roll their own solutions when putting high-tech features into rockets, and a desire to include a microcontroller in a rocket while still keeping things flexible and modular is what led [concretedog] to design a system using 22 mm diameter stackable PCBs designed to easily fit inside rocket bodies. The system uses a couple of 2 mm threaded rods for robust mounting and provides an ATTiny85 microcontroller, power control, and an optional small prototyping area. Making self-contained modular sleds that fit easily into rocket bodies (or any tube with a roughly one-inch inner diameter) is much easier as a result.

The original goal was to ease the prototyping of microcontroller-driven functions like delayed ignition or altimeter triggers in small Estes rockets, but [concretedog] felt there were probably other uses for the boards as well and made the design files available on GitHub. (Thanks!)

We have seen stackable PCBs for rocketry before with the amazingly polished M3 Avionics project, but [concretedog]’s design is much more accessible to some hobbyist-level tinkering; especially since the ATTiny85 can be programmed using the Arduino IDE and the boards themselves are just an order from OSH Park away.

[via Dangerous Prototypes Blog]


Continuity Tester uses the ATtiny85’s Comparator

There’s an inside joke among cyclists – the number of bikes you need is “n+1”, where “n” is your current number of bikes. The same probably also applies to the number of tools and equipment a hacker needs on their workbench. Enough is never enough. Although [David Johnson-Davies] has a couple of multimeters lying around, he still felt the urge to build a stand-alone continuity tester and has posted details for a super-simple ATtiny85 based Continuity Tester on his blog. For a device this simple, he set himself some tall design goals. Using the ATtiny85 and a few SMD discretes, he built a handy tester that met all of his requirements and then some.

The ATtiny85’s Analog Comparator function is perfectly suited for such a tester. One input of the comparator is biased such that there is a 51 ohm resistor between the input and ground. The output of the comparator toggles when the resistance between the other input and ground is either higher or lower than 51 ohms. Enabling internal pullup resistors in the ATtiny85 not only takes care of proper biasing of the comparator pins, but also helps reduce current consumption when the ATtiny85 is put to sleep. The test current is limited to 100 μA, making the tester suitable for use in sensitive electronics. And enabling the sleep function after 60 seconds of inactivity reduces standby current to just about 1 μA, so there is no need for a power switch. [David] reckons the CR927 button cell ought to last pretty long.

For those interested in building this handy tester, [David] has shared the Eagle CAD files as well as the ATtiny85 code on his Github repository or you could just order out some boards from OSHpark.

Hackaday Links: June 11, 2017

PCB art is getting better and better every year. This year, though, is knocking it out of the park. In March, [Andrew Sowa] turned me into money. More recently, [Trammell Hudson] has explored the layers of OSH Park soldermask and silk to create a masterpiece. Now, we’re moving up to full-blown art. [Blake Ramsdell] worked with OSH Park to create a full panel of art in gold, fiberglass, soldermask, and silkscreen. It’s 22×16 inches, and it’s fantastic.

There’s an independent Hackaday meetup going down in Hong Kong this week. The subject of the meetup will be vacuum systems for electron beam melting, mass spectrometry, and building Nixie tubes.

Why does my circuit still work when I remove some caps? This question was posed to the EEVBlog forums, with a picture attached of  the worst mess of wires I’ve ever seen. This is — supposedly — not a joke, and a complete, functional CPU built out of 74HC series logic on thirty or so solderless breadboards. A weird bonus of access to the tip line at Hackaday means everyone here becomes experts in the field of absurdly constructed electronics. Want to see the worst PCB ever? We’ve seen it. This is, without question, the most rats nest electronic project anyone has ever built.

[Adam West] died this weekend at the age of 88. [West] is perhaps best known for his performance in Lookwell as a crime-solving, washed-up TV action hero. He is survived by his wife, Marcelle, and six children.

There’s a new documentary on [Nolan Bushnell] and the early days of Atari. Documentarian [Bruno Grampa] will be showing his latest, Easy to Learn, Hard to Master at the Computer History Museum in Mountain View on June 23rd. It’s narrated by [Bil Herd], so we’re a bit prejudiced, but check out the trailer.

How To Fix Your Broken Onion Omega2

A decade ago, while RISC architecture was busy changing everything and people were wearing Utilikilts without beards, hackers were doing something amazing. They repurposed off-the-shelf routers and turned them into what we would now call the Internet of Things. Need to set up a PBX? A Linksys router will do it. Want to drive a remote control car over the Internet? It’s your old friend, WRT54G.

Now that the Internet of Things is a thing, a few companies have realized people will buy bare bones router chipsets. It’s like an Arduino, or something, and it connects to the Internet. We’ll sell a million. Get Indiegogo on the phone.

The Onion Omega2 launched on Kickstarter last year, and so far has seen some success. They’ve shipped their units, and people are generally happy with them. One thing that wasn’t mentioned in the Kickstarter was the fundamental problem with the design. The pins on this seemingly breadboard-compatible dev board have a pitch of two millimeters. Horribly broken. Huge mistake. Terrible deal.  Not the best people we have working on this.

Imperial is a superior unit of measurement. Metric is outdated.

The Onion Omega2 won’t fit in a breadboard, but Onion does offer a breakout ‘expansion dock’ for $15 USD. There’s a better, cheaper solution, though. You can complain about it on’s Hack Chat. That’s what [zach] did, and a few minutes later, [davedarko] whipped up a quick PCB design to convert the 2mm header to the much more logical 0.1 inch header. Imperial units win once again.

After sending three dollars and twenty cents to OSHPark, [zach] had his pin adapters in hand. A few minutes with a soldering iron, and the Onion Omega2 is made compatible with every breadboard ever made.

If you have an Onion Omega2 and would like a really cool hexagonal sticker, here’s the project on OSHPark.

A Completely Open Microcontroller

An annotated mRISCV die image

We don’t know about you, but the idea of an Arduino-class microprocessor board which uses completely open silicon is a pretty attractive prospect to us. That’s exactly [onchipUIS]’s stated goal. They’re part of a research group at the Universidad Industrial de Santander and have designed and taped out a RISCV implementation with Cortex M0-like characteristics.

The RISCV project has developed an open ISA (instruction set architecture) for modern 32-bit CPUs. More than 40 research groups and companies have now jumped on the project and are putting implementations together.

[onchipUIS] is one such project. And their twitter timeline shows the rapid progress they’ve been making recently.

Die directly bonded to an OSHPark PCB

After tapeout, they started experimenting with their new wirebonding machine. Wirebonding, particularly manual bonding, on a novel platform is a process fraught with problems. Not only have [onchipUIS] successfully bonded their chip, but they’ve done so using a chip on board process where the die is directly bonded to a PCB. They used OSHPark boards and described the process on Twitter.

The board they’ve built breaks out all the chip’s peripherals, and is a convenient test setup to help them validate the platform. Check it, and some high resolution die images, out below. They’re also sending us a die to image using our electron microscope down at hackerfarm, and we look forward to the results!

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